National Library of Energy BETA

Sample records for acrf pyrgeometer blackbody

  1. Improvements in the Blackbody Calibration of Pyrgeometers (Presentation)

    SciTech Connect (OSTI)

    Reda, I.; Grobner, J.; Stoffel, T.; Myers, D.; Forgan, B.

    2008-03-01

    Pyrgeometers are used to measure the atmospheric longwave irradiance throughout the ARM program sites. Previous calibrations of pyrgeometers using ARM/Eppley/NREL blackbody were consistent, but introduced a difference in the historical clear sky measured irradiance. This difference was believed to be in the order of 12 W/m2. In this poster we show the improvements to the blackbody and calibration methodology by comparing our results to the results of a group of pyrgeometers that were recently calibrated against the World Infrared Standard Group, in the World Radiation Center, Davos/Switzerland.

  2. Absolute cavity pyrgeometer

    DOE Patents [OSTI]

    Reda, Ibrahim

    2013-10-29

    Implementations of the present disclosure involve an apparatus and method to measure the long-wave irradiance of the atmosphere or long-wave source. The apparatus may involve a thermopile, a concentrator and temperature controller. The incoming long-wave irradiance may be reflected from the concentrator to a thermopile receiver located at the bottom of the concentrator to receive the reflected long-wave irradiance. In addition, the thermopile may be thermally connected to a temperature controller to control the device temperature. Through use of the apparatus, the long-wave irradiance of the atmosphere may be calculated from several measurements provided by the apparatus. In addition, the apparatus may provide an international standard of pyrgeometers' calibration that is traceable back to the International System of Units (SI) rather than to a blackbody atmospheric simulator.

  3. Calibrating Pyrgeometers Outdoors Independent from the Reference Value of the Atmospheric Longwave Irradiance

    SciTech Connect (OSTI)

    Reda, I.; Hickey, J. R.; Grobner, J.; Andreas, A.; Stoffel, T.

    2006-08-01

    In this article, we describe a method for the calibration of thermopile pyrgeometers in the absence of a reference for measurement of atmospheric longwave irradiance. This is referred to as the incoming longwave irradiance in this article. The method is based on an indoor calibration using a low-temperature blackbody source to obtain the calibration coefficients that determine the pyrgeometer's radiation characteristics. From these coefficients the outgoing irradiance of the pyrgeometer can be calculated. The pyrgeometer is then installed outdoors on an aluminum plate that is connected to a circulating temperature bath. By adjusting the temperature bath to the approximate value of the effective sky temperature, the pyrgeometer's body temperature is lowered changing the pyrgeometer's thermopile output. If the incoming longwave irradiance is stable, the slope of the outgoing irradiance versus the pyrgeometer's thermopile output is the outdoor net irradiance responsivity (RSnet), independent of the absolute value of the atmospheric longwave irradiance. The indoor calibration coefficients and the outdoor RSnet are then used in the pyrgeometer equation to calculate the incoming longwave irradiance. To evaluate this method, the calculated irradiance using the derived coefficients was compared to the irradiance measured using a pyrgeometer with direct traceability to the World Infrared Standard Group (WISG). This is maintained at the Physikalisch-Meteorologisches Observatorium Davos, World Radiation Center, Switzerland. Based on results from four pyrgeometers calibrations, this method suggests measurement agreement with the WISG to within +/- 3 W/m2 for all sky conditions.

  4. Introducing an Absolute Cavity Pyrgeometer for Improving the Atmospheric Longwave Irradiance Measurement (Presentation)

    SciTech Connect (OSTI)

    Reda, I.; Hansen, L.; Zeng, J.

    2012-08-01

    Advancing climate change research requires accurate and traceable measurement of the atmospheric longwave irradiance. Current measurement capabilities are limited to an estimated uncertainty of larger than +/- 4 W/m2 using the interim World Infrared Standard Group (WISG). WISG is traceable to the Systeme international d'unites (SI) through blackbody calibrations. An Absolute Cavity Pyrgeometer (ACP) is being developed to measure absolute outdoor longwave irradiance with traceability to SI using the temperature scale (ITS-90) and the sky as the reference source, instead of a blackbody. The ACP was designed by NREL and optically characterized by the National Institute of Standards and Technology (NIST). Under clear-sky and stable conditions, the responsivity of the ACP is determined by lowering the temperature of the cavity and calculating the rate of change of the thermopile output voltage versus the changing net irradiance. The absolute atmospheric longwave irradiance is then calculated with an uncertainty of +/- 3.96 W/m2 with traceability to SI. The measured irradiance by the ACP was compared with the irradiance measured by two pyrgeometers calibrated by the World Radiation Center with traceability to the WISG. A total of 408 readings was collected over three different clear nights. The calculated irradiance measured by the ACP was 1.5 W/m2 lower than that measured by the two pyrgeometers that are traceable to WISG. Further development and characterization of the ACP might contribute to the effort of improving the uncertainty and traceability of WISG to SI.

  5. Uncertainty Estimates for SIRS, SKYRAD, & GNDRAD Data and Reprocessing the Pyrgeometer Data (Presentation)

    SciTech Connect (OSTI)

    Reda, I.; Stoffel, T.; Habte, A.

    2014-03-01

    The National Renewable Energy Laboratory (NREL) and the Atmospheric Radiation Measurement (ARM) Climate Research Facility work together in providing data from strategically located in situ measurement observatories around the world. Both work together in improving and developing new technologies that assist in acquiring high quality radiometric data. In this presentation we summarize the uncertainty estimates of the ARM data collected at the ARM Solar Infrared Radiation Station (SIRS), Sky Radiometers on Stand for Downwelling Radiation (SKYRAD), and Ground Radiometers on Stand for Upwelling Radiation (GNDRAD), which ultimately improve the existing radiometric data. Three studies are also included to show the difference between calibrating pyrgeometers (e.g., Eppley PIR) using the manufacturer blackbody versus the interim World Infrared Standard Group (WISG), a pyrgeometer aging study, and the sampling rate effect of correcting historical data.

  6. Introducing an Absolute Cavity Pyrgeometer (ACP) for Improving the Atmospheric Longwave Irradiance Measurement (Poster)

    SciTech Connect (OSTI)

    Reda, I.; Stoffel, T.

    2012-03-01

    Advancing climate change research requires accurate and traceable measurement of the atmospheric longwave irradiance. Current measurement capabilities are limited to an estimated uncertainty of larger than +/- 4 W/m2 using the interim World Infrared Standard Group (WISG). WISG is traceable to the Systeme international d'unites (SI) through blackbody calibrations. An Absolute Cavity Pyrgeometer (ACP) is being developed to measure absolute outdoor longwave irradiance with traceability to SI using the temperature scale (ITS-90) and the sky as the reference source, instead of a blackbody. The ACP was designed by NREL and optically characterized by the National Institute of Standards and Technology (NIST). Under clear-sky and stable conditions, the responsivity of the ACP is determined by lowering the temperature of the cavity and calculating the rate of change of the thermopile output voltage versus the changing net irradiance. The absolute atmospheric longwave irradiance is then calculated with an uncertainty of +/- 3.96 W/m2 with traceability to SI. The measured irradiance by the ACP was compared with the irradiance measured by two pyrgeometers calibrated by the World Radiation Center with traceability to the WISG.

  7. ACRF Data Collection and Processing Infrastructure

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.TheoryTuesday, August 10, 20102016 News BelowAsked toUSC-Aiken,AUii ABSTRACT46 ACRF

  8. ACRF Ingest Software Status: New, Current, and Future - March 2008

    SciTech Connect (OSTI)

    AS Koontz; S Choudhury; BD Ermold; NN Keck; KL Gaustad; RC Perez

    2008-03-01

    The purpose of this report is to provide status of the ingest software used to process instrument data for the Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF). The report is divided into four sections: (1) news about ingests currently under development, (2) current production ingests, (3) future ingest development plans, and (4) information on retired ingests. Please note that datastreams beginning in “xxx” indicate cases where ingests run at multiple ACRF sites, which results in a datastream(s) for each location.

  9. Absolute Cavity Pyrgeometer to Measure the Absolute Outdoor Longwave Irradiance with Traceability to International System of Units, SI

    SciTech Connect (OSTI)

    Reda, I.; Zeng, J.; Scheuch, J.; Hanssen, L.; Wilthan, B.; Myers, D.; Stoffel, T.

    2012-03-01

    This article describes a method of measuring the absolute outdoor longwave irradiance using an absolute cavity pyrgeometer (ACP), U.S. Patent application no. 13/049, 275. The ACP consists of domeless thermopile pyrgeometer, gold-plated concentrator, temperature controller, and data acquisition. The dome was removed from the pyrgeometer to remove errors associated with dome transmittance and the dome correction factor. To avoid thermal convection and wind effect errors resulting from using a domeless thermopile, the gold-plated concentrator was placed above the thermopile. The concentrator is a dual compound parabolic concentrator (CPC) with 180{sup o} view angle to measure the outdoor incoming longwave irradiance from the atmosphere. The incoming irradiance is reflected from the specular gold surface of the CPC and concentrated on the 11 mm diameter of the pyrgeometer's blackened thermopile. The CPC's interior surface design and the resulting cavitation result in a throughput value that was characterized by the National Institute of Standards and Technology. The ACP was installed horizontally outdoor on an aluminum plate connected to the temperature controller to control the pyrgeometer's case temperature. The responsivity of the pyrgeometer's thermopile detector was determined by lowering the case temperature and calculating the rate of change of the thermopile output voltage versus the changing net irradiance. The responsivity is then used to calculate the absolute atmospheric longwave irradiance with an uncertainty estimate (U{sub 95}) of {+-}3.96 W m{sup 02} with traceability to the International System of Units, SI. The measured irradiance was compared with the irradiance measured by two pyrgeometers calibrated by the World Radiation Center with traceability to the Interim World Infrared Standard Group, WISG. A total of 408 readings were collected over three different nights. The calculated irradiance measured by the ACP was 1.5 W/m{sup 2} lower than that measured by the two pyrgeometers that are traceable to WISG, with a standard deviation of {+-}0.7 W m{sup -2}. These results suggest that the ACP design might be used for addressing the need to improve the international reference for broadband outdoor longwave irradiance measurements.

  10. ACRF Ingest Software Status: New, Current, and Future - June 2008

    SciTech Connect (OSTI)

    AS Koontz; S Choudhury; BD Ermold; NN Keck; KL Gaustad; RC Perez

    2008-06-01

    The purpose of this report is to provide status of the ingest software used to process instrument data for the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF). The report is divided into 4 sections: (1) for news about ingests currently under development, (2) for current production ingests, (3) for future ingest development plans, and (4) for information on retired ingests. Please note that datastreams beginning in “xxx” indicate cases where ingests run at multiple ACRF sites, which results in a datastream(s) for each location.

  11. ACRF Ingest Software Status: New, Current, and Future - May 2008

    SciTech Connect (OSTI)

    AS Koontz; S Choudhury; BD Ermold; N N Keck; KL Gaustad; RC Perez

    2008-05-01

    The purpose of this report is to provide status of the ingest software used to process instrument data for the Atmospheric Radiation Measurement Program Climate Research Facility (ACRF). The report is divided into 4 sections: (1) for news about ingests currently under development, (2) for current production ingests, (3) for future ingest development plans, and (4) for information on retired ingests. Please note that datastreams beginning in “xxx” indicate cases where ingests run at multiple ACRF sites, which results in a datastream(s) for each location.

  12. ACRF Ingest Software Status: New, Current, and Future - April 2008

    SciTech Connect (OSTI)

    AS Koontz; S Choudhury; BD Ermold; NN Keck; KL Gaustad; RC Perez

    2008-04-01

    The purpose of this report is to provide status of the ingest software used to process instrument data for the Atmospheric Radiation Measurement Program Climate Research Facility (ACRF). The report is divided into 4 sections: (1) for news about ingests currently under development, (2) for current production ingests, (3) for future ingest development plans, and (4) for information on retired ingests. Please note that datastreams beginning in “xxx” indicate cases where ingests run at multiple ACRF sites, which results in a datastream(s) for each location.

  13. ACRF Instrumentation Status: New, Current, and Future - September – October 2007

    SciTech Connect (OSTI)

    JW Voyles

    2007-10-30

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) instrumentation status. The report is divided into the following four sections: (1) new instrumentation in the process of being acquired and deployed, (2) existing instrumentation and progress on improvements or upgrades, (3) proposed future instrumentation, and (4) SBIR instrument development.

  14. ACRF Instrumentation Status: New, Current, and Future - October – November 2007

    SciTech Connect (OSTI)

    JW Voyles

    2007-11-30

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) instrumentation status. The report is divided into the following four sections: (1) new instrumentation in the process of being acquired and deployed, (2) existing instrumentation and progress on improvements or upgrades, (3) proposed future instrumentation, and (4) SBIR instrument development.

  15. ACRF Instrumentation Status: New, Current, and Future July 2007

    SciTech Connect (OSTI)

    JC Liljegren

    2007-07-01

    The purpose of this report is to provide a concise but comprehensive overview of ACRF instrumentation status. The report is divided into four sections: (1) new instrumentation in the process of being acquired and deployed, (2) existing instrumentation and progress on improvements or upgrades, (3) proposed future instrumentation, and (4) SBIR instrument development.

  16. Scientific Guidance, Research, and Educational Outreach for the ARM Climate Research Facility (ACRF) in the Southern Great Plains

    SciTech Connect (OSTI)

    Lamb, Peter J.

    2013-06-13

    Scientific Guidance, Research, and Educational Outreach for the ARM Climate Research Facility (ACRF) in the Southern Great Plains

  17. Atmospheric Radiation Measurement Climate Research Facility (ACRF) Annual Report 2007

    SciTech Connect (OSTI)

    LR Roeder

    2007-12-01

    This annual report describes the purpose and structure of the program, and presents key accomplishments in 2007. Notable achievements include: • Successful review of the ACRF as a user facility by the DOE Biological and Environmental Research Advisory Committee. The subcommittee reinforced the importance of the scientific impacts of this facility, and its value for the international research community. • Leadership of the Cloud Land Surface Interaction Campaign. This multi-agency, interdisciplinary field campaign involved enhanced surface instrumentation at the ACRF Southern Great Plains site and, in concert with the Cumulus Humilis Aerosol Processing Study sponsored by the DOE Atmospheric Science Program, coordination of nine aircraft through the ARM Aerial Vehicles Program. • Successful deployment of the ARM Mobile Facility in Germany, including hosting nearly a dozen guest instruments and drawing almost 5000 visitors to the site. • Key advancements in the representation of radiative transfer in weather forecast models from the European Centre for Medium-Range Weather Forecasts. • Development of several new enhanced data sets, ranging from best estimate surface radiation measurements from multiple sensors at all ACRF sites to the extension of time-height cloud occurrence profiles to Niamey, Niger, Africa. • Publication of three research papers in a single issue (February 2007) of the Bulletin of the American Meteorological Society.

  18. Results of Second Outdoor Comparison Between Absolute Cavity Pyrgeometer (ACP) and Infrared Integrating Sphere (IRIS) Radiometer at PMOD (Presentation)

    SciTech Connect (OSTI)

    Reda, I.; Grobner, J.; Wacker, S.

    2014-01-01

    The Absolute Cavity Pyrgeometer (ACP) and InfraRed Integrating Sphere radiometer (IRIS) are developed to establish a world reference for calibrating pyrgeometers with traceability to SI units. The two radiometers are un-windowed with negligible spectral dependence, and traceable to SI units through the temperature scale (ITS-90). The second outdoor comparison between the two designs was held from September 30 to October 11, 2013 at the Physikalisch-Metorologisches Observatorium Davos (PMOD). The difference between the irradiance measured by ACP and that of the IRIS was within 1 W/m2 (3 IRISs: PMOD + Australia + Germany). From the first and second comparisons, a difference of 4-6 W/m2 was observed between the irradiance measured by ACP&IRIS and that of the interim World Infrared Standard Group (WISG). This presentation includes results from the first and second comparison in an effort to establish the world reference for pyrgeometer calibrations, a key deliverable for the World Meteorological Organization (WMO), and the DOE-ASR.

  19. Results of First Outdoor Comparison Between Absolute Cavity Pyrgeometer (ACP) and Infrared Integrating Sphere (IRIS) Radiometer at PMOD (Presentation)

    SciTech Connect (OSTI)

    Reda, I.; Grobner, J.; Wacker, S.; Stoffel, T.

    2013-03-01

    The ACP and IRIS are developed to establish a world reference for calibrating pyrgeometers with traceability to SI units. The two radiometers are unwindowed with negligible spectral dependence, and traceable to SI units through the temperature scale (ITS-90). The first outdoor comparison between the two designs was held from January 28 to February 8, 2013 at the Physikalisch-Metorologisches Observatorium Davos (PMOD). The difference between the irradiance measured by ACP and that of IRIS was within 1 W/m2. A difference of 5 W/m2 was observed between the irradiance measured by ACP&IRIS and that of the interim World Infrared Standard Group (WISG).

  20. Atmospheric Radiation Measurement Climate Research Facility (ACRF) Annual Report 2008

    SciTech Connect (OSTI)

    LR Roeder

    2008-12-01

    The Importance of Clouds and Radiation for Climate Change: The Earth’s surface temperature is determined by the balance between incoming solar radiation and thermal (or infrared) radiation emitted by the Earth back to space. Changes in atmospheric composition, including greenhouse gases, clouds, and aerosols, can alter this balance and produce significant climate change. Global climate models (GCMs) are the primary tool for quantifying future climate change; however, there remain significant uncertainties in the GCM treatment of clouds, aerosol, and their effects on the Earth’s energy balance. In 1989, the U.S. Department of Energy (DOE) Office of Science created the Atmospheric Radiation Measurement (ARM) Program to address scientific uncertainties related to global climate change, with a specific focus on the crucial role of clouds and their influence on the transfer of radiation in the atmosphere. To reduce these scientific uncertainties, the ARM Program uses a unique twopronged approach: • The ARM Climate Research Facility, a scientific user facility for obtaining long-term measurements of radiative fluxes, cloud and aerosol properties, and related atmospheric characteristics in diverse climate regimes; and • The ARM Science Program, focused on the analysis of ACRF and other data to address climate science issues associated with clouds, aerosols, and radiation, and to improve GCMs. This report provides an overview of each of these components and a sample of achievements for each in fiscal year (FY) 2008.

  1. Noncommutative Black-Body Radiation: Implications On Cosmic Microwave Background

    E-Print Network [OSTI]

    Amir H. Fatollahi; Maryam Hajirahimi

    2006-07-12

    Including loop corrections, black-body radiation in noncommutative space is anisotropic. A direct implication of possible space noncommutativity on the Cosmic Microwave Background map is argued.

  2. HISTORY AND CURRENT STATUS OF THE CIMEL SUN-PHOTOMETERS AT ACRF SITES

    E-Print Network [OSTI]

    HISTORY AND CURRENT STATUS OF THE CIMEL SUN-PHOTOMETERS AT ACRF SITES L. Gregory and R. Wagener operational revisions: (1) adding serial line data collection and internet transfer, and (2) adding the zenith-pointing cloud mode. We review the time-line and history of these changes and describe plans for adding

  3. Black-Body Radiation Of Noncommutative Gauge Fields

    E-Print Network [OSTI]

    A. H. Fatollahi; M. Hajirahimi

    2006-11-21

    The black-body radiation is considered in a theory with noncommutative electromagnetic fields; that is noncommutativity is introduced in field space, rather than in real space. A direct implication of the result on Cosmic Microwave Background map is argued.

  4. Design, manufacture, and calibration of infrared radiometric blackbody sources

    SciTech Connect (OSTI)

    Byrd, D.A.; Michaud, F.D.; Bender, S.C.

    1996-04-01

    A Radiometric Calibration Station (RCS) is being assembled at the Los Alamos National Laboratories (LANL) which will allow for calibration of sensors with detector arrays having spectral capability from about 0.4-15 {mu}m. The configuration of the LANL RCS. Two blackbody sources have been designed to cover the spectral range from about 3-15 {mu}m, operating at temperatures ranging from about 180-350 K within a vacuum environment. The sources are designed to present a uniform spectral radiance over a large area to the sensor unit under test. The thermal uniformity requirement of the blackbody cavities has been one of the key factors of the design, requiring less than 50 mK variation over the entire blackbody surface to attain effective emissivity values of about 0.999. Once the two units are built and verified to the level of about 100 mK at LANL, they will be sent to the National Institute of Standards and Technology (NIST), where at least a factor of two improvement will be calibrated into the blackbody control system. The physical size of these assemblies will require modifications of the existing NIST Low Background Infrared (LBIR) Facility. LANL has constructed a bolt-on addition to the LBIR facility that will allow calibration of our large aperture sources. Methodology for attaining the two blackbody sources at calibrated levels of performance equivalent to present state of the art will be explained in the following.

  5. An electronic radiation of blackbody: Cosmic electron background

    E-Print Network [OSTI]

    Jian-Miin Liu

    2008-02-23

    The Universe owns the electronic radiation of blackbody at temperature 2.725 K, which we call the cosmic electron background. We calculate its radiation spectrum. The energy distribution of number density of electrons in the cosmic electron background becomes zero as energy goes to both zero and infinity. It has one maximum peak near the energy level of 10**(-23) J.

  6. Quantum driven dissipative parametric oscillator in a blackbody radiation field

    SciTech Connect (OSTI)

    Pachón, Leonardo A.; Department of Chemistry and Center for Quantum Information and Quantum Control, Chemical Physics Theory Group, University of Toronto, Toronto, Ontario M5S 3H6 ; Brumer, Paul

    2014-01-15

    We consider the general open system problem of a charged quantum oscillator confined in a harmonic trap, whose frequency can be arbitrarily modulated in time, that interacts with both an incoherent quantized (blackbody) radiation field and with an arbitrary coherent laser field. We assume that the oscillator is initially in thermodynamic equilibrium with its environment, a non-factorized initial density matrix of the system and the environment, and that at t = 0 the modulation of the frequency, the coupling to the incoherent and the coherent radiation are switched on. The subsequent dynamics, induced by the presence of the blackbody radiation, the laser field, and the frequency modulation, is studied in the framework of the influence functional approach. This approach allows incorporating, in analytic closed formulae, the non-Markovian character of the oscillator-environment interaction at any temperature as well the non-Markovian character of the blackbody radiation and its zero-point fluctuations. Expressions for the time evolution of the covariance matrix elements of the quantum fluctuations and the reduced density-operator are obtained.

  7. White Noise, Black-body radiation and Secure communication

    E-Print Network [OSTI]

    C. Tannous; J. Langlois

    2015-06-05

    Nyquist White noise derivation based on blackbody radiation interacting with electrons in a transmission line is revisited and is shown to possibly pave the way toward secure noise-based communication systems. Encrypting a message for secure transmission might be performed by combining it with controlled noise as performed in Spread-Spectrum communication that are presently used in Telecommunication systems. Quantum communication using entanglement is another route for secure communications as demonstrated by several important experiments. Classical and Quantum noise are compared and discussed as a major constituent of secure communication.

  8. On the Dynamics of a Small Rotating Particle Moving in Blackbody Radiation

    E-Print Network [OSTI]

    A. A. Kyasov; G. V. Dedkov

    2015-12-09

    Based on the general expressions for the tangential force and heating rate of a small polarizable particle during translational-rotational motion in the field of blackbody radiation (in the reference frame of latter),the tangential force in reference frame comoving with particle is calculated. It is this force determines the particle deceleration in the frame of reference of blackbody radiation.

  9. Pressure-sensitive blackbody point radiation induced by infrared diode laser irradiation

    E-Print Network [OSTI]

    Cao, Wenwu

    Pressure-sensitive blackbody point radiation induced by infrared diode laser irradiation Feng Qin,1, by irradiation of well-matched infrared (IR) lasers upon the Yb3þ ions, ultrabroadband luminescence can

  10. Neutron star blackbody contraction during flaring in X1624-490

    E-Print Network [OSTI]

    M. Balucinska-Church; R. Barnard; M. J. Church; A. P. Smale

    2001-10-01

    We present results of an investigation of the physical changes taking place in the emission regions of the LMXB X1624-490 during strong flaring in RXTE observations. Based on the detailed light curve, we propose that the flaring consists of a superposition of X-ray bursts. It is shown that major changes take place in the blackbody emission component, the temperature kT_BB increasing to ~2.2 keV in flaring. Remarkably, the blackbody area decreases by a factor of ~5 in flaring. During flare evolution, the blackbody luminosity remains approximately constant, constituting a previously unknown Eddington limiting effect which we propose is due to radiation pressure of the blackbody as kT_BB increases affecting the inner disk or accretion flow resulting in a decreased emitting area on the star. We argue that the large decrease in area cannot be explained in terms of modification of the blackbody spectrum by electron scattering in the atmosphere of the neutron star. The height of the emitting region on the non-flaring neutron star is shown to agree with the height of the inner radiatively-supported disk as found for sources in the ASCA survey of LMXB of Church & Balucinska-Church (2001). The decrease in height during flaring is discussed in terms of possible models, including radial accretion flow onto the stellar surface and the theory of accretion flow spreading on the neutron star surface of Inogamov & Sunyaev (1999). We demonstrate that the intensity of the broad iron line at 6.4 keV is strongly correlated with the luminosity of the blackbody emission from the neutron star, and discuss the probable origin of this line in the ADC. Finally, possible reasons for non-detection of a reflection component in this source, and LMXB in general, are discussed.

  11. The Status of the ACRF Millimeter Wave Cloud Radars (MMCRs), the Path Forward for Future MMCR Upgrades, the Concept of 3D Volume Imaging Radar and the UAV Radar

    SciTech Connect (OSTI)

    P Kollias; MA Miller; KB Widener; RT Marchand; TP Ackerman

    2005-12-30

    The United States (U.S.) Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) operates millimeter wavelength cloud radars (MMCRs) in several climatological regimes. The MMCRs, are the primary observing tool for quantifying the properties of nearly all radiatively important clouds over the ACRF sites. The first MMCR was installed at the ACRF Southern Great Plains (SGP) site nine years ago and its original design can be traced to the early 90s. Since then, several MMCRs have been deployed at the ACRF sites, while no significant hardware upgrades have been performed. Recently, a two-stage upgrade (first C-40 Digital Signal Processors [DSP]-based, and later the PC-Integrated Radar AcQuisition System [PIRAQ-III] digital receiver) of the MMCR signal-processing units was completed. Our future MMCR related goals are: 1) to have a cloud radar system that continues to have high reliability and uptime and 2) to suggest potential improvements that will address increased sensitivity needs, superior sampling and low cost maintenance of the MMCRs. The Traveling Wave Tube (TWT) technology, the frequency (35-GHz), the radio frequency (RF) layout, antenna, the calibration and radar control procedure and the environmental enclosure of the MMCR remain assets for our ability to detect the profile of hydrometeors at all heights in the troposphere at the ACRF sites.

  12. Entropy and complexity properties of the d-dimensional blackbody radiation

    E-Print Network [OSTI]

    Toranzo, I V

    2015-01-01

    Space dimensionality is a crucial variable in the analysis of the structure and dynamics of natural systems and phenomena. The dimensionality effects of the blackbody radiation has been the subject of considerable research activity in recent years. These studies are still somewhat fragmentary, pos- ing formidable qualitative and quantitative problems for various scientific and technological areas. In this work we carry out an information-theoretical analysis of the spectral energy density of a d-dimensional blackbody at temperature T by means of various entropy-like quantities (disequilibrium, Shannon entropy, Fisher information) as well as by three (dimensionless) complexity measures (Cr\\'amer-Rao, Fisher-Shannon and LMC). All these frequency-functional quantities are calculated and discussed in terms of temperature and dimensionality. It is shown that all three measures of complexity have an universal character in the sense that they depend neither on temperature nor on the Planck and Boltzmann constants, b...

  13. Entropy and complexity properties of the d-dimensional blackbody radiation

    E-Print Network [OSTI]

    I. V. Toranzo; J. S. Dehesa

    2014-09-03

    Space dimensionality is a crucial variable in the analysis of the structure and dynamics of natural systems and phenomena. The dimensionality effects of the blackbody radiation has been the subject of considerable research activity in recent years. These studies are still somewhat fragmentary, pos- ing formidable qualitative and quantitative problems for various scientific and technological areas. In this work we carry out an information-theoretical analysis of the spectral energy density of a d-dimensional blackbody at temperature T by means of various entropy-like quantities (disequilibrium, Shannon entropy, Fisher information) as well as by three (dimensionless) complexity measures (Cr\\'amer-Rao, Fisher-Shannon and LMC). All these frequency-functional quantities are calculated and discussed in terms of temperature and dimensionality. It is shown that all three measures of complexity have an universal character in the sense that they depend neither on temperature nor on the Planck and Boltzmann constants, but only on the the space dimensionality d. Moreover, they decrease when d is increasing; in particular, the values 2.28415, 1.90979 and 1.17685 are found for the Cr\\'amer-Rao, Fisher-Shannon and LMC measures of complexity of the 3-dimensional blackbody radiation, respectively. In addition, beyond the frequency at which the spectral density is maximum (which follows the well-known Wien displacement law), three further characteristic frequencies are defined in terms of the previous entropy quantities; they are shown to obey Wien-like laws. The potential usefulness of these distinctive features of the blackbody spectrum is physically discussed.

  14. High temperature blackbody BB2000/40 for calibration of radiation thermometers and thermocouple

    SciTech Connect (OSTI)

    Ogarev, S. A.; Khlevnoy, B. B.; Samoylov, M. L.; Puzanov, A. V. [All-Russian Research Institute for Optical and Physical Measurements (VNIIOFI), Moscow (Russian Federation)] [All-Russian Research Institute for Optical and Physical Measurements (VNIIOFI), Moscow (Russian Federation)

    2013-09-11

    The cavity-type high temperature blackbody (HTBB) models of BB3200/3500 series are the most spread among metrological institutes worldwide as sources for radiometry and radiation thermometry, due to their ultra high working temperatures, high emissivity and stability. The materials of radiating cavities are graphite, pyrolytic graphite (PG) and their combination. The paper describes BB2000/40 blackbody with graphite-tube cavity that was developed for calibration of radiation thermometers at SCEI (Singapore). The peculiarity of BB2000/40 is a possibility to use it, besides calibration of pyrometers, as an instrument for thermocouples calibration. Operating within the temperature range from 900 °C to 2000 °C, the blackbody has a wide cavity opening of 40 mm. Emissivity of the cavity, with PG heater rings replaced partly by graphite elements, was estimated as 0.998 ± 0.0015 in the spectral range from 350 nm to 2000 nm. The uniformity along the cavity axis, accounting for 10 °C, was measured using a B-type thermocouple at 1500 °C. The BB2000/40, if necessary, can be easily modified, by replacing the graphite radiator with a set of PG rings, to be able to reach temperatures as high as 3200 °C. The HTBB utilizes an optical feedback system which allows temperature stabilization within 0.1 °C. This rear-view feedback allows the whole HTBB aperture to be used for measurements.

  15. Blackbody material

    DOE Patents [OSTI]

    Lauf, Robert J. (Oak Ridge, TN); Hamby, Jr., Clyde (Harriman, TN); Akerman, M. Alfred (Knoxville, TN); Trivelpiece, Alvin W. (Oak Ridge, TN)

    1994-01-01

    A light emitting article comprises a composite of carbon-bonded carbon fibers, prepared by: blending carbon fibers with a carbonizable organic powder to form a mixture; dispersing the mixture into an aqueous slurry; vacuum molding the aqueous slurry to form a green article; drying and curing the green article to form a cured article; and, carbonizing the cured article at a temperature of at least about 1000.degree. C. to form a carbon-bonded carbon fiber light emitting composite article having a bulk density less than 1 g/cm.sup.3.

  16. The Blackbody Radiation Laws in the $ \\textrm{AdS}_5 \\times {\\cal S}^5 $ Spacetime

    E-Print Network [OSTI]

    Ramaton Ramos; Henrique Boschi-Filho

    2015-04-25

    In the footsteps of our previous work \\cite{RamatonBoschi} we generalize the Stefan-Boltzmann and Wien's displacement laws for the $ \\textrm{AdS}_5 \\times {\\cal S}^5 $ spacetime, the background of the AdS/CFT correspondence foremost realization. Our results take into account the $ \\textrm{AdS}_5 \\times {\\cal S}^5 $ full dimensionality in the electromagnetic field $A^{\\mu}$ wave equation, which yields the higher-dimensional blackbody characteristic features suggested in literature. In particular, the total radiated power and the spectral radiancy match the original Stefan-Boltzmann and Wien's displacement laws in the low-energy regime up to available experimental data.

  17. A New Blackbody Radiation Law Based on Fractional Calculus and its Application to NASA COBE Data

    E-Print Network [OSTI]

    Minoru Biyajima; Takuya Mizoguchi; Naomichi Suzuki

    2015-08-20

    By applying fractional calculus to the equation proposed by M. Planck in 1900, we obtain a new blackbody radiation law described by a Mittag-Leffler (ML) function. We have analyzed NASA COBE data by means of a non-extensive formula with a parameter $(q-1)$, a formula proposed by Ertik et al. with a fractional parameter $(\\alpha-1)$, and our new formula including a parameter $(p-1)$, as well as the Bose-Einstein distribution with a dimensionless chemical potential $\\mu$. It can be said that one role of the fractional parameter $(p-1)$ is almost the same as that of chemical potential $(\\mu)$ as well as that of the parameter $(q-1)$ in the non-extensive approach.

  18. Radiometric characterization of a high temperature blackbody in the visible and near infrared

    SciTech Connect (OSTI)

    Taubert, R. D.; Hollandt, J.

    2013-09-11

    At the Physikalisch-Technische Bundesanstalt the radiance temperature in the range from 962 °C to 3000 °C is disseminated by applying a high temperature blackbody (HTBB) with a directly heated pyrolytic graphite cavity. The thermodynamic radiance temperature of the HTBB was measured in the temperature range from 1000 °C to 3000 °C by applying almost simultaneously absolutely calibrated silicon photodiode based filter radiometers with centre wavelengths at 476 nm, 676 nm, 800 nm, 900 nm and 1000 nm and InGaAs photodiode based filter radiometers with centre wavelengths at 1300 nm, 1550 nm and 1595 nm. The results demonstrate that, expressed in terms of irradiance, within an uncertainty of 0.1 % (k=1) in a broad wavelength range the thermodynamic radiance temperature of the HTBB is wavelength independent in the investigated temperature interval.

  19. ACRF-Newsletter.indd

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach HomeA Better Anode Design to Improve4AJ01) (See Energy Level79AJ01) (NotAdvanced ABSTRACTSFor centuries,

  20. ARM - Field Campaign - International Pyrgeometer Intercomparison

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach HomeA Better Anode Design to Improve4AJ01)govCampaignsFIRE-Arctic- Hemispheric

  1. Evaluation of Improved Pyrgeometer Calibration Method

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submitKansasCommunitiesof Energy8) Wigner Home ·the Effect

  2. Simple analytical approximations for treatment of inverse Compton scattering of relativistic electrons in the blackbody radiation field

    SciTech Connect (OSTI)

    Khangulyan, D. [Institute of Space and Astronautical Science/JAXA, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Aharonian, F. A. [Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2 (Ireland); Kelner, S. R., E-mail: khangul@astro.isas.jaxa.jp, E-mail: Felix.Aharonian@mpi-hd.mpg.de, E-mail: Stanislav.Kelner@mpi-hd.mpg.de [Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany)

    2014-03-10

    The inverse Compton (IC) scattering of relativistic electrons is one of the major gamma-ray production mechanisms in different environments. Often, the target photons for IC scattering are dominated by blackbody (or graybody) radiation. In this case, the precise treatment of the characteristics of IC radiation requires numerical integrations over the Planckian distribution. Formally, analytical integrations are also possible but they result in series of several special functions; this limits the efficiency of usage of these expressions. The aim of this work is the derivation of approximate analytical presentations that would provide adequate accuracy for the calculations of the energy spectra of upscattered radiation, the rate of electron energy losses, and the mean energy of emitted photons. Such formulae have been obtained by merging the analytical asymptotic limits. The coefficients in these expressions are calculated via the least-squares fitting of the results of numerical integrations. The simple analytical presentations, obtained for both the isotropic and anisotropic target radiation fields, provide adequate (as good as 1%) accuracy for broad astrophysical applications.

  3. AMIE (ACRF MJO Investigation Experiment)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach HomeA Better Anode Design to Improve4AJ01) (See Energy Level79AJ01)19^560AMERICA'S NATIONAL LABS by 50

  4. ACRF Newsletter_May_FINAL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach HomeA Better Anode Design to Improve4AJ01) (See Energy Level79AJ01) (NotAdvanced ABSTRACTS

  5. Microsoft PowerPoint - ARM_pyrgeometer.ppt

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on darkMicroorganisms to SpeedJacksonville,Measuresof

  6. ACRF Instrumentation Status and Information April 2009

    SciTech Connect (OSTI)

    JW Voyles

    2009-05-07

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Climate Research Facility instrumentation status. The report is divided into the following five sections: (1) new instrumentation in the process of being acquired and deployed, (2) field campaigns, (3) existing instrumentation and progress on improvements or upgrades, (4) proposed future instrumentation, and (5) Small Business Innovation Research instrument development.

  7. Constraining primordial magnetic fields with distortions of the black-body spectrum of the cosmic microwave background: pre- and post-decoupling contributions

    SciTech Connect (OSTI)

    Kunze, Kerstin E. [Departamento de Física Fundamental and IUFFyM, Universidad de Salamanca, Plaza de la Merced s/n, 37008 Salamanca (Spain); Komatsu, Eiichiro, E-mail: kkunze@usal.es, E-mail: komatsu@mpa-garching.mpg.de [Max-Planck-Institut für Astrophysik, Karl-Schwarzschild Str. 1, 85741 Garching (Germany)

    2014-01-01

    Primordial magnetic fields that exist before the photon-baryon decoupling epoch are damped on length scales below the photon diffusion and free-streaming scales. The energy injected into the plasma by dissipation of magnetosonic and Alfv and apos;en waves heats photons, creating a y-type distortion of the black-body spectrum of the cosmic microwave background. This y-type distortion is converted into a ?-type distortion when elastic Compton scattering is efficient. Therefore, we can use observational limits on y- and ?-type distortions to constrain properties of magnetic fields in the early universe. Assuming a Gaussian, random, and non-helical field, we calculate ? and y as a function of the present-day strength of the field, B{sub 0}, smoothed over a certain Gaussian width, k{sub c}{sup ?1}, as well as of the spectral index of the power spectrum of fields, n{sub B}, defined by P{sub B}(k)?k{sup n{sub B}}. For a nearly scale-invariant spectrum with n{sub B} = ?2.9 and a Gaussian smoothing width of k{sub c}{sup ?1} = 1Mpc, the existing COBE/FIRAS limit on ? yields B{sub 0} < 40 nG, whereas the projected PIXIE limit on ? would yield B{sub 0} < 0.8 nG. For non-scale-invariant spectra, constraints can be stronger. For example, for B{sub 0} = 1 nG with k{sub c}{sup ?1} = 1Mpc, the COBE/FIRAS limit on ? excludes a wide range of spectral indices given by n{sub B} > ?2.6. After decoupling, energy dissipation is due to ambipolar diffusion and decaying MHD turbulence, creating a y-type distortion. The distortion is completely dominated by decaying MHD turbulence, and is of order y ? 10{sup ?7} for a few nG field smoothed over the damping scale at the decoupling epoch, k{sub d,} {sub dec} ? 290(B{sub 0}/1nG){sup ?1}Mpc{sup ?1}. The projected PIXIE limit on y would exclude B{sub 0} > 1.0 and 0.6 nG for n{sub B} = ?2.9 and -2.3, respectively, and B{sub 0} > 0.6 nG for n{sub B} ? 2. Finally, we find that the current limits on the optical depth to Thomson scattering restrict the predicted y-type distortion to be y?<10{sup ?8}.

  8. Near-Blackbody Enclosed Particle Receiver

    Broader source: Energy.gov [DOE]

    This presentation was delivered at the SunShot Concentrating Solar Power (CSP) Program Review 2013, held April 23–25, 2013 near Phoenix, Arizona.

  9. ACRF Instrumentation Status: New, Current, and Future August 2006

    SciTech Connect (OSTI)

    JC Liljegren

    2006-08-01

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Program Climate Research Facility instrumentation status. The report is divided into four sections: (1) new instrumentation in the process of being acquired and deployed, (2) existing instrumentation and progress on improvements or upgrades, (3) proposed future instrumentation, and (4) Small Business Innovation Research instrument development. New information is highlighted in blue text.

  10. ACRF Instrumentation Status: New, Current, and Future - June 2008

    SciTech Connect (OSTI)

    JW Voyles

    2008-07-01

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Climate Research Facility instrumentation status. The report is divided into the following five sections: (1) new instrumentation in the process of being acquired and deployed, (2) field campaigns, (3) existing instrumentation and progress on improvements or upgrades, (4) proposed future instrumentation, and (5) Small Business Innovation Research instrument development.

  11. ACRF Instrumentation Status: New, Current, and Future May 2007

    SciTech Connect (OSTI)

    JC Liljegren

    2007-04-01

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Program Climate Research Facility instrumentation status. The report is divided into four sections: (1) new instrumentation in the process of being acquired and deployed, (2) existing instrumentation and progress on improvements or upgrades, (3) proposed future instrumentation, and (4) Small Business Innovation Research instrument development.

  12. ACRF Instrumentation Status: New, Current, and Future - August 2008

    SciTech Connect (OSTI)

    JW Voyles

    2008-09-01

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Climate Research Facility instrumentation status. The report is divided into the following five sections: (1) new instrumentation in the process of being acquired and deployed, (2) field campaigns, (3) existing instrumentation and progress on improvements or upgrades, (4) proposed future instrumentation, and (5) Small Business Innovation Research instrument development.

  13. ACRF Instrumentation Status: New, Current, and Future - January 2009

    SciTech Connect (OSTI)

    JW Voyles

    2009-03-02

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Climate Research Facility instrumentation status. The report is divided into the following five sections: (1) new instrumentation in the process of being acquired and deployed, (2) field campaigns, (3) existing instrumentation and progress on improvements or upgrades, (4) proposed future instrumentation, and (5) Small Business Innovation Research instrument development.

  14. ACRF Instrumentation Status: New, Current, and Future June 2007

    SciTech Connect (OSTI)

    JC Liljegren

    2007-06-01

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Program Climate Research Facility instrumentation status. The report is divided into four sections: (1) new instrumentation in the process of being acquired and deployed, (2) existing instrumentation and progress on improvements or upgrades, (3) proposed future instrumentation, and (4) Small Business Innovation Research instrument development.

  15. ACRF Instrumentation Status: New, Current, and Future September 2006

    SciTech Connect (OSTI)

    JC Liljegren

    2006-09-01

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Program Climate Research Facility instrumentation status. The report is divided into four sections: (1) new instrumentation in the process of being acquired and deployed, (2) existing instrumentation and progress on improvements or upgrades, (3) proposed future instrumentation, and (4) Small Business Innovation Research instrument development. New information is highlighted in blue text.

  16. ACRF Instrumentation Status: New, Current, and Future - November – December 2007

    SciTech Connect (OSTI)

    JW Voyles

    2007-12-01

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Climate Research Facility instrumentation status. The report is divided into the following four sections: (1) new instrumentation in the process of being acquired and deployed, (2) existing instrumentation and progress on improvements or upgrades, (3) proposed future instrumentation, and (4) Small Business Innovation Research instrument development.

  17. ACRF Instrumentation Status: New, Current, and Future - July 2008

    SciTech Connect (OSTI)

    JW Voyles

    2008-07-01

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Climate Research Facility instrumentation status. The report is divided into the following five sections: (1) new instrumentation in the process of being acquired and deployed, (2) field campaigns, (3) existing instrumentation and progress on improvements or upgrades, (4) proposed future instrumentation, and (5) Small Business Innovation Research instrument development.

  18. ACRF Instrumentation Status: New, Current, and Future - April 2008

    SciTech Connect (OSTI)

    JW Voyles

    2008-05-01

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Climate Research Facility instrumentation status. The report is divided into the following five sections: (1) new instrumentation in the process of being acquired and deployed, (2) field campaigns, (3) existing instrumentation and progress on improvements or upgrades, (4) proposed future instrumentation, and (5) Small Business Innovation Research instrument development.

  19. ACRF Instrumentation Status: New, Current, and Future - December 2008

    SciTech Connect (OSTI)

    JW Voyles

    2009-01-15

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Climate Research Facility instrumentation status. The report is divided into the following five sections: (1) new instrumentation in the process of being acquired and deployed, (2) field campaigns, (3) existing instrumentation and progress on improvements or upgrades, (4) proposed future instrumentation, and (5) Small Business Innovation Research instrument development.

  20. ACRF Instrumentation Status: New, Current, and Future - March 2008

    SciTech Connect (OSTI)

    JW Voyles

    2008-04-01

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Climate Research Facility instrumentation status. The report is divided into the following four sections: (1) new instrumentation in the process of being acquired and deployed, (2) existing instrumentation and progress on improvements or upgrades, (3) proposed future instrumentation, and (4) Small Business Innovation Research instrument development.

  1. ACRF Instrumentation Status: New, Current, and Future - October 2008

    SciTech Connect (OSTI)

    JW Voyles

    2008-10-01

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Climate Research Facility instrumentation status. The report is divided into the following five sections: (1) new instrumentation in the process of being acquired and deployed, (2) field campaigns, (3) existing instrumentation and progress on improvements or upgrades, (4) proposed future instrumentation, and (5) Small Business Innovation Research instrument development.

  2. ACRF Instrumentation Status: New, Current, and Future May 2007

    SciTech Connect (OSTI)

    JC Liljegren

    2007-05-01

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Program Climate Research Facility instrumentation status. The report is divided into four sections: (1) new instrumentation in the process of being acquired and deployed, (2) existing instrumentation and progress on improvements or upgrades, (3) proposed future instrumentation, and (4) Small Business Innovation Research instrument development.

  3. ACRF Instrumentation Status: New, Current, and Future March 2007

    SciTech Connect (OSTI)

    JC Liljegren

    2007-03-01

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Program Climate Research Facility instrumentation status. The report is divided into four sections: (1) new instrumentation in the process of being acquired and deployed, (2) existing instrumentation and progress on improvements or upgrades, (3) proposed future instrumentation, and (4) Small Business Innovation Research instrument development.

  4. ACRF Instrumentation Status: New, Current, and Future - May 2008

    SciTech Connect (OSTI)

    JW Voyles

    2008-05-01

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Climate Research Facility instrumentation status. The report is divided into the following five sections: (1) new instrumentation in the process of being acquired and deployed, (2) field campaigns, (3) existing instrumentation and progress on improvements or upgrades, (4) proposed future instrumentation, and (5) Small Business Innovation Research instrument development.

  5. ACRF Instrumentation Status: New, Current, and Future October 2006

    SciTech Connect (OSTI)

    JC Liljegren

    2006-10-01

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Program Climate Research Facility instrumentation status. The report is divided into four sections: (1) new instrumentation in the process of being acquired and deployed, (2) existing instrumentation and progress on improvements or upgrades, (3) proposed future instrumentation, and (4) Small Business Innovation Research instrument development.

  6. ACRF Instrumentation Status: New, Current, and Future February 2007

    SciTech Connect (OSTI)

    JC Liljegren

    2007-02-01

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Program Climate Research Facility instrumentation status. The report is divided into four sections: (1) new instrumentation in the process of being acquired and deployed, (2) existing instrumentation and progress on improvements or upgrades, (3) proposed future instrumentation, and (4) Small Business Innovation Research instrument development

  7. ACRF Instrumentation Status: New, Current, and Future July 2006

    SciTech Connect (OSTI)

    JC Liljegren

    2006-07-01

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Program Climate Research Facility instrumentation status. The report is divided into four sections: (1) new instrumentation in the process of being acquired and deployed, (2) existing instrumentation and progress on improvements or upgrades, (3) proposed future instrumentation, and (4) Small Business Innovation Research instrument development. New information is highlighted in blue text.

  8. ACRF Instrumentation Status: New, Current, and Future March 2009

    SciTech Connect (OSTI)

    JW Voyles

    2009-03-15

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Climate Research Facility instrumentation status. The report is divided into the following five sections: (1) new instrumentation in the process of being acquired and deployed, (2) field campaigns, (3) existing instrumentation and progress on improvements or upgrades, (4) proposed future instrumentation, and (5) Small Business Innovation Research instrument development.

  9. ACRF Instrumentation Status: New, Current, and Future February 2009

    SciTech Connect (OSTI)

    JW Voyles

    2009-02-15

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Climate Research Facility instrumentation status. The report is divided into the following five sections: (1) new instrumentation in the process of being acquired and deployed, (2) field campaigns, (3) existing instrumentation and progress on improvements or upgrades, (4) proposed future instrumentation, and (5) Small Business Innovation Research instrument development.

  10. ACRF Instrumentation Status: New, Current, and Future - November 2008

    SciTech Connect (OSTI)

    JW Voyles

    2008-12-01

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Climate Research Facility instrumentation status. The report is divided into the following five sections: (1) new instrumentation in the process of being acquired and deployed, (2) field campaigns, (3) existing instrumentation and progress on improvements or upgrades, (4) proposed future instrumentation, and (5) Small Business Innovation Research instrument development.

  11. ACRF Instrumentation Status: New, Current, and Future January 2007

    SciTech Connect (OSTI)

    JC Liljegren

    2007-01-01

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Program Climate Research Facility instrumentation status. The report is divided into four sections: (1) new instrumentation in the process of being acquired and deployed, (2) existing instrumentation and progress on improvements or upgrades, (3) proposed future instrumentation, and (4) Small Business Innovation Research instrument development.

  12. ACRF Instrumentation Status: New, Current, and Future - September 2008

    SciTech Connect (OSTI)

    JW Voyles

    2008-10-15

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Climate Research Facility instrumentation status. The report is divided into the following five sections: (1) new instrumentation in the process of being acquired and deployed, (2) field campaigns, (3) existing instrumentation and progress on improvements or upgrades, (4) proposed future instrumentation, and (5) Small Business Innovation Research instrument development.

  13. ACRF Instrumentation Status: New, Current, and Future - February 2008

    SciTech Connect (OSTI)

    JW Voyles

    2008-03-01

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Climate Research Facility instrumentation status. The report is divided into the following four sections: (1) new instrumentation in the process of being acquired and deployed, (2) existing instrumentation and progress on improvements or upgrades, (3) proposed future instrumentation, and (4) Small Business Innovation Research instrument development.

  14. ARM - Field Campaign - AMIE (ACRF MJO Investigation Experiment):

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach HomeA Better Anode Design to Improve4AJ01) (See22, 2012III ARM Data Discovery Browse DataIV

  15. Radiative Closure Studies at the NSA ACRF Site

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMassR&D100 Winners * Impacts on GlobalRachel Ruggirello RachelRadiation

  16. George Smoot, Blackbody, and Anisotropy of the Cosmic Microwave Background

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformation Current HABFESOpportunities NuclearlongGeneral

  17. DOE/SC-ARM/P-07-002.3 ACRF Instrumentation Status: New, Current, and Future

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submit theCovalent Bonding Low-Cost2 DOE HQSiteo n n e v i2 ARM Climate162 Sonde3103

  18. DOE/SC-ARM/P-07-002.7 ACRF Instrumentation Status: New, Current, and Future

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submit theCovalent Bonding Low-Cost2 DOE HQSiteo n n e v i2 ARM Climate162 Sonde31037

  19. Atmospheric Radiation Measurement Climate Research Facility (ACRF Instrumentation Status: New, Current, and Future)

    SciTech Connect (OSTI)

    JW Voyles

    2008-01-30

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Climate Research Facility instrumentation status. The report is divided into the following four sections: (1) new instrumentation in the process of being acquired and deployed, (2) existing instrumentation and progress on improvements or upgrades, (3) proposed future instrumentation, and (4) Small Business Innovation Research instrument development.

  20. ACRF Instrumentation Status: New, Current, and Future November-December 2006

    SciTech Connect (OSTI)

    JC Liljegren

    2006-12-01

    The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Program Climate Research Facility instrumentation status. The report is divided into four sections: (1) new instrumentation in the process of being acquired and deployed, (2) existing instrumentation and progress on improvements or upgrades, (3) proposed future instrumentation, and (4) Small Business Innovation Research instrument development.

  1. Temporal Variability of Fair-Weather Cumulus Statistics at the ACRF SGP Site

    SciTech Connect (OSTI)

    Berg, Larry K.; Kassianov, Evgueni I.

    2008-07-01

    Continental fair-weather cumuli exhibit significant diurnal, day-to-day, and year-to-year variability. This study describes the climatology of cloud macroscale properties, including the cloud-base height, cloud-top height, cloud thickness, and cloud chord length over the U.S. Department of Energy¹s Atmospheric Radiation Measurement (ARM) Climate Research Facility (ARCF) Southern Great Plains (SGP) site. The diurnal cycle of cloud fraction, cloud-base height, and cloud-thickness were well defined. The cloud fraction reached its maximum value near 14:00 CST. The average cloud-base height increased throughout the day, while the average cloud thickness decreased with time. In contrast to the other cloud properties, the average cloud-chord length remained nearly constant throughout the day. The sensitivity of the cloud properties to the year-to-year variability and to changes in low-level moisture were compared. The cloud-base height was found to be sensitive to both the year and the low-level moisture, the cloud thickness was much more sensitive to the year then to the low-level moisture, and the cloud fraction and cloud chord length were more sensitive to the low-level moisture than to the year. Distributions of the cloud-chord length over the ARCF SGP site were computed and were well fit by an exponential distribution. The contribution of clouds of each cloud-chord length to the total cloud fraction was computed, and it was found the clouds with a chord length of about 1 km contributed the most to the observed cloud fraction.

  2. Microsoft Word - ACRF4thQuarterFY09 draft_nb__sal.doc

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on77 PAGE OF PAGESpersonal informationAGENCY RECORD OF78 3.National16

  3. ORNL, ACRF Archive: Raymond McCord, Giri Palanisamy, Karen Gibson, W. Christopher Lenhardt

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shinesSolarNewsusceptometer underIRossybelle PeralesORN L/TM-- 1217 6

  4. Seasonal And Decadal Variation of the Mixed Layer Across the ACRF Using RWP Data

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust, High-ThroughputUpcomingmagnetoresistance |Komlov,Search / Search Search

  5. Use of Long Time-series ACRF Measurements to Improve Data Quality Analysis

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorking With WIPPfinalUnexpectedofWyko NT33004.Department ofARM/NSAUse2, 2008

  6. Initial Evaluation of the Cumulus Potential Scheme at the ACRF SGP Site

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would likeUniverseIMPACT EVALUATION PLAN FOR0987P Uncertainty inInhibitingSciTech

  7. Finite Cloud Effects at the ACRF TWP Site Patrick Taylor and Robert G. Ellingson

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would likeUniverse (Journal Article) |Final Reportthe Growing American AutoStocksFinite

  8. Microsoft Word - ACRF3rdQuarterFY09_DOE_SC_ARM_P_09_011.doc

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on77 PAGE OF PAGESpersonal informationAGENCY RECORD OF78 3.National1

  9. Emission and absorption of photons and the black-body spectra in Lorentz-odd Electrodynamics

    E-Print Network [OSTI]

    J. M. Fonseca; A. H. Gomes; W. A. Moura-Melo

    2008-09-03

    We study a number of issues related to the emission and absorption radiation by non-relativistic electrons within the framework of a Lorentz-breaking electrodynamics in (3+1) dimensions. Our main results concern how Planck-like spectrum law is sensitive to terms that violate Lorentz symmetry. We have realized that Planck law acquires extra terms proportional to the violating parameters: for the CPT-odd model, the leading extra terms appear to be linear or quadratic in these violating parameters according to the background vector is parallel or perpendicular to the photon wave-vector. In the CPT-even case a linear `correction' shows up. Among other possible ways to probe for these violations, by means of the present results, we may quote the direct observation of the extra contributions or an unbalancing in the mean occupation number of photon modes in a given thermal bath.

  10. Global warming and its implications for conservation. 2. How does it work? Part one: greenhouse gasses and blackbody

    E-Print Network [OSTI]

    Creel, Scott

    -----------] High H20 Low H20 Low energy (J/g) High energy ( J/g) Oil and natural gas: reduced aquatic plants fossil fuels (coal, oil, natural gas) to produce energy. Almost all energy on earth ultimately comes from, with high temperature, pressure and anaerobic conditions. Coal: reduced terrestrial plants, mainly peat

  11. Thermal radiation and blackbody radiation drag of a large-sized perfectly black particle moving with relativistic velocity

    E-Print Network [OSTI]

    Kyasov, A A

    2015-01-01

    We have developed a self-consistent description of the radiation heat transfer and dynamics of large perfectly black spherical bodies with sizes much greater than the characteristic wavelength of radiation moving in a photon gas with relativistic velocity. The results can be important in astrophysics.

  12. Indirect and Semi-Direct Aerosol Campaign

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Liu, Shaocheng Xie Barrow, Alaska April 2008 http:acrf-campaign.arm.govisdac Motivation * Summertime Arctic sea ice has decreased dramatically in recent years, beyond...

  13. What is the ARM Climate Research Facility: Is Global Warming a Real Bias or a Statistical Anomaly?

    SciTech Connect (OSTI)

    Egami, Takeshi; Sisterson, Douglas L.

    2010-03-10

    The Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) is a U.S. Department of Energy, Office of Science, Office of Biological and Environmental Research national user facility. With multi-laboratory management of distributed facilities worldwide, the ACRF does not fit the mold of a traditional user facility located at a national laboratory. The ACRF provides the world's most comprehensive 24/7 observational capabilities for obtaining atmospheric data specifically for climate change research. Serving nearly 5,000 registered users from 15 federal and state agencies, 375 universities, and 67 countries, the ACRF Data Archive collects and delivers over 5 terabytes of data per month to its users. The ACRF users provide critical information about cloud formation processes, water vapor, and aerosols, and their influence on radiative transfer in the atmosphere. This information is used to improve global climate model predictions of climate change.

  14. Microsoft Word - 2009-04 Instrument Report_DOE-SC-ARM-P=09.004.4.doc

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on77 PAGE OF PAGESpersonal information is revealed2 ACRF3 ACRF4 ACRF

  15. Microsoft Word - 2009-05 Instrument Report DOE-SC-ARM-P-09-004.5.doc

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on77 PAGE OF PAGESpersonal information is revealed2 ACRF3 ACRF4 ACRF5

  16. Microsoft Word - 2009-07 Instrument Report_DOE-SC-ARM-P-09-004.7.doc

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on77 PAGE OF PAGESpersonal information is revealed2 ACRF3 ACRF47 ACRF

  17. ARM Climate Modeling Best Estimate from Manus Island, PNG with additional satellite product (ARMBE-CLDRAD TWPC1 V2.1a)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    2011-02-07

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  18. ARM Climate Modeling Best Estimate from Nauru (ARMBE-CLDRAD TWPC2 V2.1)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    2010-08-11

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  19. ARM Climate Modeling Best Estimate Barrow, AK (ARMBE-CLDRAD NSAC1)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    2012-05-14

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  20. ARM Climate Modeling Best Estimate Barrow, AK (ARMBE-CLDRAD NSAC1 V2.1)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    2010-08-11

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  1. ARM Climate Modeling Best Estimate from Nauru with additional satellite product (ARMBE-CLDRAD TWPC2 V2.1a)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    2011-02-07

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  2. ARM Climate Modeling Best Estimate from Manus Island, PNG (ARMBE-CLDRAD TWPC1 V2.1)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    2011-02-07

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  3. ARM Climate Modeling Best Estimate from Darwin, AU with additional satellite product (ARMBE-CLDRAD TWPC3 V2.1a)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    2011-02-07

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  4. ARM Climate Modeling Best Estimate from Nauru (ARMBE-CLDRAD TWPC1)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    2012-05-14

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  5. ARM Climate Modeling Best Estimate from Nauru (ARMBE-CLDRAD TWPC2)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    2012-05-14

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  6. ARM Climate Modeling Best Estimate from Nauru (ARMBE-CLDRAD TWPC3)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    2012-05-14

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  7. ARM Climate Modeling Best Estimate Lamont, OK (ARMBE-CLDRAD SGPC1)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    2012-02-20

    The ARM CMBE-CLDRAD [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected cloud and radiation relevant quantities from ACRF observations

  8. ARM Climate Modeling Best Estimate Lamont, OK (ARMBE-CLDRAD SGPC1)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    2012-05-14

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  9. ARM Climate Modeling Best Estimate from Darwin, AU (ARMBE-CLDRAD TWPC3 V2.1)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    2010-08-10

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  10. ARM Climate Modeling Best Estimate Barrow, AK with additional satellite product (ARMBE-CLDRAD NSAC1 V2.1a)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    2011-02-07

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  11. ARM Climate Modeling Best Estimate From Darwin, AU (ARMBE-ATM TWPC3)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  12. ARM Climate Modeling Best Estimate Barrow, AK (ARMBE-ATM NSAC1)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  13. ARM Climate Modeling Best Estimate From Darwin, AU (ARMBE-ATM TWPC2)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  14. ARM Climate Modeling Best Estimate Lamont, OK (ARMBE-ATM SGPC1)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  15. ARM Climate Modeling Best Estimate From Manus Island, PNG (ARMBE-ATM TWPC1)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  16. ARM Climate Modeling Best Estimate Barrow, AK (ARMBE-ATM NSAC1 V4)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  17. ARM Climate Modeling Best Estimate From Nauru (ARMBE-ATM TWPC2)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  18. Large-Eddy Observation of Post-Cold-Frontal Continental Stratocumulus

    E-Print Network [OSTI]

    Mechem, David B.; Kogan, Yefim L.; Schultz, David M.

    2010-10-01

    and continental stratocumulus to each other, the approach of large-eddy observation (LEO) was applied to a case of nocturnal continental stratocumulus observed over the Atmospheric Radiation Measurement Program (ARM) Climate Research Facility (ACRF) in the central...

  19. ARM Climate Modeling Best Estimate From Manus Island, PNG (ARMBE-ATM TWPC1)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    2012-05-14

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  20. ARM Climate Modeling Best Estimate From Darwin, AU (ARMBE-ATM TWPC2)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    2013-12-26

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  1. ARM Climate Modeling Best Estimate Barrow, AK (ARMBE-ATM NSAC1)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    2010-10-05

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  2. ARM Climate Modeling Best Estimate From Manus Island, PNG (ARMBE-ATM TWPC1)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    2013-12-26

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  3. ARM Climate Modeling Best Estimate Barrow, AK (ARMBE-ATM NSAC1 V4)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    2013-12-26

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  4. ARM Climate Modeling Best Estimate From Darwin, AU (ARMBE-ATM TWPC3)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    2013-12-26

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  5. ARM Climate Modeling Best Estimate From Nauru (ARMBE-ATM TWPC2)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    2010-10-05

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  6. ARM Climate Modeling Best Estimate Lamont, OK (ARMBE-ATM SGPC1)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    2013-12-26

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  7. ARM Climate Modeling Best Estimate Lamont, OK (ARMBE-ATM SGPC1)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    2012-05-14

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  8. ARM Climate Modeling Best Estimate From Darwin, AU (ARMBE-ATM TWPC3)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    2010-10-05

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  9. ARM Climate Modeling Best Estimate From Manus Island, PNG (ARMBE-ATM TWPC1)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    2010-10-05

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  10. ARM Climate Modeling Best Estimate From Darwin, AU (ARMBE-ATM TWPC3)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    2013-12-27

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  11. ARM Climate Modeling Best Estimate Lamont, OK (ARMBE-ATM SGPC1)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    2011-12-13

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  12. ARM Climate Modeling Best Estimate Lamont, OK (ARMBE-CLDRAD SGPC1)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    The ARM CMBE-CLDRAD [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected cloud and radiation relevant quantities from ACRF observations

  13. ARM Climate Modeling Best Estimate from Nauru (ARMBE-CLDRAD TWPC1)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  14. ARM Climate Modeling Best Estimate from Darwin, AU (ARMBE-CLDRAD TWPC3 V2.1)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  15. ARM Climate Modeling Best Estimate from Darwin, AU with additional satellite product (ARMBE-CLDRAD TWPC3 V2.1a)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  16. ARM Climate Modeling Best Estimate from Manus Island, PNG with additional satellite product (ARMBE-CLDRAD TWPC1 V2.1a)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  17. ARM Climate Modeling Best Estimate from Nauru with additional satellite product (ARMBE-CLDRAD TWPC2 V2.1a)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  18. ARM Climate Modeling Best Estimate from Nauru (ARMBE-CLDRAD TWPC3)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  19. ARM Climate Modeling Best Estimate from Manus Island, PNG (ARMBE-CLDRAD TWPC1 V2.1)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  20. ARM Climate Modeling Best Estimate from Nauru (ARMBE-CLDRAD TWPC2)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  1. ARM Climate Modeling Best Estimate Barrow, AK (ARMBE-CLDRAD NSAC1)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  2. ARM Climate Modeling Best Estimate Lamont, OK (ARMBE-CLDRAD SGPC1)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  3. ARM Climate Modeling Best Estimate Barrow, AK with additional satellite product (ARMBE-CLDRAD NSAC1 V2.1a)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  4. ARM Climate Modeling Best Estimate from Nauru (ARMBE-CLDRAD TWPC2 V2.1)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  5. ARM Climate Modeling Best Estimate Barrow, AK (ARMBE-CLDRAD NSAC1 V2.1)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    McCoy, Renata; Xie, Shaocheng

    The ARM CMBE-ATM [Xie, McCoy, Klein et al.] data file contains a best estimate of several selected atmospheric quantities from ACRF observations and NWP analysis data.

  6. Green Bank Weather Dana S. Balser

    E-Print Network [OSTI]

    Balser, Dana S.

    Green Bank Weather Dana S. Balser #12;Weather Resources 1. Weather Stations 2. Weather Forecasts (NOAA/Maddalena) 3. Pyrgeometer 4. 86 GHz Tipping Radiometer 5. 12 GHz Interferometer #12;Weather Parameters 1 May 2004 to 1 March 2007 speedwindousInstantaneV :Hz)(12StationWeather e

  7. DATA META FILE 2012 This file describes the instrumentation, field setup, and quality control procedures

    E-Print Network [OSTI]

    Minnesota, University of

    Variable Units Instrument *Notes 1 Year 2 Day 3 Hour 4 Solar radiation (K) W/m2 Eppley PSP 3.7 m 5 Reflected Solar Radiation W/m2 Eppley PSP 3.7 m 6 Incoming longwave radiation W/m2 Eppley Pyrgeometer 7 of the climate variables to date and is subject to revision. See dates above for recent updates concerning

  8. DATA META FILE 2011 This file describes the instrumentation, field setup, and quality control procedures

    E-Print Network [OSTI]

    Minnesota, University of

    Variable Units Instrument *Notes 1 Year 2 Day 3 Hour 4 Solar radiation (K) W/m2 Eppley PSP 3.7 m 5 Reflected Solar Radiation W/m2 Eppley PSP 3.7 m 6 Incoming longwave radiation W/m2 Eppley Pyrgeometer 7 of the climate variables to date and is subject to revision. See dates above for recent updates concerning

  9. New and Improved Data Logging and Collection System for Atmospheric Radiation Measurement Climate Research Facility, Tropical Western Pacific, and North Slope of Alaska Sky Radiation, Ground Radiation, and MET Systems

    SciTech Connect (OSTI)

    Ritsche, M.T.; Holdridge, D.J.; Pearson, R.

    2005-03-18

    Aging systems and technological advances mandated changes to the data collection systems at the Atmospheric Radiation Measurement (ARM) Program's Tropical Western Pacific (TWP) and North Slope of Alaska (NSA) ARM Climate Research Facility (ACRF) sites. Key reasons for the upgrade include the following: achieve consistency across all ACRF sites for easy data use and operational maintenance; minimize the need for a single mentor requiring specialized knowledge and training; provide local access to real-time data for operational support, intensive operational period (IOP) support, and public relations; eliminate problems with physical packaging (condensation, connectors, etc.); and increase flexibility in programming and control of the data logger.

  10. Nauru Island Effect Detection Data Set

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Long, Chuck

    2010-07-15

    During Nauru99 it was noted that the island was producing small clouds that advected over the ARM site. The Nauru Island Effect Study was run for 1.5 years and the methodology developed to detect the occurrence. Nauru ACRF downwelling SW, wind direction, and air temperature data are used, along with downwelling SW data from Licor radiometers located on the southern end of the island near the airport landing strip. A statistical analysis and comparison of data from the two locations is used to detect the likely occurrence of an island influence on the Nauru ACRF site data

  11. ARM Climate Research Facility Annual Report 2005

    SciTech Connect (OSTI)

    J. Voyles

    2005-12-31

    Through the ARM Program, the DOE funded the development of several highly instrumented ground stations for studying cloud formation processes and their influence on radiative transfer, and for measuring other parameters that determine the radiative properties of the atmosphere. This scientific infrastructure, and resultant data archive, is a valuable national and international asset for advancing scientific knowledge of Earth systems. In fiscal year (FY) 2003, the DOE designated ARM sites as a national scientific user facility: the ARM Climate Research (ACRF). The ACRF has enormous potential to contribute to a wide range interdisciplinary science in areas such as meteorology, atmospheric aerosols, hydrology, biogeochemical cycling, and satellite validation, to name only a few.

  12. Nauru Island Effect Detection Data Set

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Long, Chuck

    During Nauru99 it was noted that the island was producing small clouds that advected over the ARM site. The Nauru Island Effect Study was run for 1.5 years and the methodology developed to detect the occurrence. Nauru ACRF downwelling SW, wind direction, and air temperature data are used, along with downwelling SW data from Licor radiometers located on the southern end of the island near the airport landing strip. A statistical analysis and comparison of data from the two locations is used to detect the likely occurrence of an island influence on the Nauru ACRF site data

  13. Bench-Scale Cross Flow Filtration of

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O OLaura| National2.11DESERT * LOW HILLS * PLATEAU9 ACRF21 ACRF

  14. Bench-Scale Cross Flow Filtration of

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O OLaura| National2.11DESERT * LOW HILLS * PLATEAU98 ACRF9 ACRF

  15. ARM TR-008

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsicloudden Documentation Data Management Facility009 ARM Orientation4 ACRF-0184 ACRF

  16. ARM TR-008

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsicloudden Documentation Data Management Facility009 ARM Orientation4 ACRF-0184 ACRF5

  17. ARM TR-008

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsicloudden Documentation Data Management Facility009 ARM Orientation4 ACRF-0184 ACRF56

  18. ARM TR-008

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsicloudden Documentation Data Management Facility009 ARM Orientation4 ACRF-0184 ACRF561

  19. ARM TR-008

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsicloudden Documentation Data Management Facility009 ARM Orientation4 ACRF-0184 ACRF56107

  20. Microsoft Word - 2009-03 Instrument Report_DOE-SC-ARM-P-09-004.3.doc

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on77 PAGE OF PAGESpersonal information is revealed2 ACRF3 ACRF

  1. Microsoft Word - 2009-06 Instrument Report_DOE_SC_ARM_P_09_004.6.doc

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on77 PAGE OF PAGESpersonal information is revealed2 ACRF3 ACRF4

  2. Microsoft Word - 2009-08 Instrument Report_DOE-SC-ARM-P-09-004.8.doc

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on77 PAGE OF PAGESpersonal information is revealed2 ACRF3 ACRF47

  3. Microsoft Word - 2009-09 Instrument Report_DOE-SC-ARM-P-09-004.9.doc

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on77 PAGE OF PAGESpersonal information is revealed2 ACRF3 ACRF479

  4. Microsoft Word - 2009-10 Instrument Report_DOE_SC_ARM_09-004-10_FINAL.doc

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on77 PAGE OF PAGESpersonal information is revealed2 ACRF3 ACRF4790

  5. Microsoft Word - 2009-12 Instrument Report_DOE-SC-ARM-09-004.11t.doc

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on77 PAGE OF PAGESpersonal information is revealed2 ACRF3 ACRF47901

  6. NREL Particle Receiver Will Enable High-Temperature CSP (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2014-08-01

    Near-blackbody enclosed particle receiver can support high-temperature thermal energy storage and high-efficiency power cycles.

  7. 1. Cover Sheet Proposal Title: The ARM Climate Research Facility in the Amazon Basin

    E-Print Network [OSTI]

    , will be formed once the ACRF deployment is approved. The list of co-investigators will be broadened multi-fold as the deployment develops toward 2013-4. #12;-- continued from previous page -- Brazilian-Side Scientists Co Activities Jun 2013 ­ Dec 2013, dry season, southern Amazonia in biomass-burning region, Porto Velho, Brazil

  8. GOOGLE AND GIS INTEGRATED ON THE ARM WEBSITE: A WORK IN PROGRESS

    E-Print Network [OSTI]

    GOOGLE AND GIS INTEGRATED ON THE ARM WEBSITE: A WORK IN PROGRESS A. Cialella and R. Wagener to zoom in at varying resolutions, with satellite images and/or street maps as backdrops. The ACRF GIS (ESRI ArcGIS) database was merged with Google to include markers for the SGP site facilities. A new SGP

  9. Niamey Aerosol Optical Depths

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Flynn, Connor

    2008-10-01

    MFRSR irradiance data collected during the ACRF AMF deployment in Niamey, Niger have been used to derive AOD for five wavelength channels of the MFRSR. These data have been corrected to adjust for filter drift over the course of the campaign and contamination due to forward scattering as a result of large dust particles in the atmosphere around Niamey.

  10. 1

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservationBio-InspiredAtmospheric Radiation Measurement Program Aerosol ObservingPyrgeometer

  11. Performance analysis of medium temperature non-tracking solar thermal concentrators

    E-Print Network [OSTI]

    Balkoski, Kevin

    2011-01-01

    Solar Thermal Energy 1.1.1. Physics of Solar Thermal Energy Blackbody Radiation3]. SunTherm Energy, Inc. Solar Thermal Market Research.

  12. International Journal of Thermophysics, Vol. 20, No. 5, 1999 Laser infrared photothermal radiometry (PTR) was used to measure the ther-

    E-Print Network [OSTI]

    Mandelis, Andreas

    for monitoring the modulated thermal (blackbody) radiation emitted from a material surface after photothermal to the diffusion length, u(f)m i n , Fig. 1. Sch

  13. Direct s-CO2 Reciever Development | Department of Energy

    Office of Environmental Management (EM)

    Solar Receiver for Use in a Supercritical CO2 Recompression Cycle - FY13 Q1 High-Temperature Solar Thermoelectric Generators (STEG) Near-Blackbody Enclosed Particle Receiver...

  14. ARM Quick-looks Database for North Slope Alaska (NSA) sites

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Stamnes, Knut [NSA Site Scientist

    From these pages one can monitor parts of the data acquisition process and access daily data visualizations from the different instruments. These data visualizations are produced in near real time automatically and are called Quick-Looks (QLs). The quick-looks contains unofficial data of unknown quality. Once data is released one can obtain the full data-set from any instrument available, and along with that, a statement about the data quality from the ARM archive. The database provides Quick-looks for the Barrow ACRF site (NSA C1), the Atqasuk ACRF site (NSA C2), or the SHEBA ice campaign of 1997 and 1998. As of 12-17-08, the database had more than 528,000 quick-looks available as data figures and data plots. No password is required for Quick-look access. (Specialized Interface)

  15. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report January 1 – March 31, 2007

    SciTech Connect (OSTI)

    DL Sisterson

    2007-04-01

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  16. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report January 1 - March 31, 2009

    SciTech Connect (OSTI)

    DL Sisterson

    2009-03-17

    Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  17. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report April 1 - June 30, 2008

    SciTech Connect (OSTI)

    DL Sisterson

    2008-06-01

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  18. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report - July 1 - September 30, 2008

    SciTech Connect (OSTI)

    DL Sisterson

    2008-09-30

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  19. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report - October 1 - December 31, 2008

    SciTech Connect (OSTI)

    DL Sisterson

    2009-01-15

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  20. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report - January 1 - March 31, 2008

    SciTech Connect (OSTI)

    DL Sisterson

    2008-04-01

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  1. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report October 1 - December 31, 2007

    SciTech Connect (OSTI)

    DL Sisterson

    2008-01-08

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  2. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report April 1 - June 30, 2007

    SciTech Connect (OSTI)

    DL Sisterson

    2007-07-01

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  3. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report July 1 – September 30, 2006

    SciTech Connect (OSTI)

    DL Sisterson

    2006-10-01

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year dating back to 1998.

  4. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report April 1 – June 30, 2006

    SciTech Connect (OSTI)

    DL Sisterson

    2006-07-01

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year; and (2) site and fiscal year dating back to 1998.

  5. SGP Cloud and Land Surface Interaction Campaign (CLASIC): Measurement Platforms

    SciTech Connect (OSTI)

    MA Miller; R Avissar; LK Berg; SA Edgerton; ML Fischer; TJ Jackson; B. Kustas; PJ Lamb; G McFarquhar; Q Min; B Schmid; MS Torn; DD Tuner

    2007-06-01

    The Cloud and Land Surface Interaction Campaign (CLASIC) will be conducted from June 8 to June 30, 2007, at the U.S. Department of Energy’s Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) Southern Great Plains (SGP) site. Data will be collected using eight aircraft equipped with a variety of specialized sensors, four specially instrumented surface sites, and two prototype surface radar systems. The architecture of CLASIC includes a high-altitude surveillance aircraft and enhanced vertical thermodynamic and wind profile measurements that will characterize the synoptic scale structure of the clouds and the land surface within the ACRF SGP site. Mesoscale and microscale structures will be sampled with a variety of aircraft, surface, and radar observations. An overview of the measurement platforms that will be used during the CLASIC are described in this report. The coordination of measurements, especially as it relates to aircraft flight plans, will be discussed in the CLASIC Implementation Plan.

  6. Quality Assurance of ARM Program Climate Research Facility Data

    SciTech Connect (OSTI)

    Peppler, RA; Kehoe, KE; Sonntag, KL; Bahrmann, CP; Richardson, SJ; Christensen, SW; McCord, RA; Doty, DJ; Wagener, Richard; Eagan, RC; Lijegren, JC; Orr, BW; Sisterson, DL; Halter, TD; Keck, NN; Long, CN; Macduff, MC; Mather, JH; Perez, RC; Voyles, JW; Ivey, MD; Moore, ST; Nitschke, DL; Perkins, BD; Turner, DD

    2008-03-01

    This report documents key aspects of the Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) data quality assurance program as it existed in 2008. The performance of ACRF instruments, sites, and data systems is measured in terms of the availability, usability, and accessibility of the data to a user. First, the data must be available to users; that is, the data must be collected by instrument systems, processed, and delivered to a central repository in a timely manner. Second, the data must be usable; that is, the data must be inspected and deemed of sufficient quality for scientific research purposes, and data users must be able to readily tell where there are known problems in the data. Finally, the data must be accessible; that is, data users must be able to easily find, obtain, and work with the data from the central repository. The processes described in this report include instrument deployment and calibration; instrument and facility maintenance; data collection and processing infrastructure; data stream inspection and assessment; the roles of value-added data processing and field campaigns in specifying data quality and haracterizing the basic measurement; data archival, display, and distribution; data stream reprocessing; and engineering and operations management processes and procedures. Future directions in ACRF data quality assurance also are presented.

  7. DOE/SC-ARM/P-07-004

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submit theCovalent Bonding Low-Cost2 DOE HQSiteo n n e v i2 ARM Climate1623 ACRF

  8. DOE/SC-ARM/P-07-004

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submit theCovalent Bonding Low-Cost2 DOE HQSiteo n n e v i2 ARM Climate1623 ACRF1

  9. DOE/SC-ARM/P-07-004

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submit theCovalent Bonding Low-Cost2 DOE HQSiteo n n e v i2 ARM Climate1623 ACRF12

  10. DOE/SC-ARM/P-07-004

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submit theCovalent Bonding Low-Cost2 DOE HQSiteo n n e v i2 ARM Climate1623 ACRF123

  11. DOE/SC-ARM/P-07-004

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submit theCovalent Bonding Low-Cost2 DOE HQSiteo n n e v i2 ARM Climate1623 ACRF1234

  12. DOE/SC-ARM/P-07-004

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submit theCovalent Bonding Low-Cost2 DOE HQSiteo n n e v i2 ARM Climate1623 ACRF12345

  13. Raman Lidar (RL) Handbook

    SciTech Connect (OSTI)

    Newsom, RK

    2009-03-01

    The Raman lidar at the ARM Climate Research Facility (ACRF) Southern Great Plains (SGP) Central Facility (SGPRL) is an active, ground-based laser remote sensing instrument that measures height and time resolved profiles of water vapor mixing ratio and several cloud- and aerosol-related quantities. The system is a non-commercial custom-built instrument developed by Sandia National Laboratories specifically for the ARM Program. It is fully computer automated, and will run unattended for many days following a brief (~5-minute) startup period. The self-contained system (requiring only external electrical power) is housed in a climate-controlled 8’x8’x20’ standard shipping container.

  14. Bench-Scale Cross Flow Filtration of

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O OLaura| National2.11DESERT * LOW HILLS * PLATEAU9 ACRF

  15. Bench-Scale Cross Flow Filtration of

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O OLaura| National2.11DESERT * LOW HILLS * PLATEAU9 ACRF2 ARM

  16. Bench-Scale Cross Flow Filtration of

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O OLaura| National2.11DESERT * LOW HILLS * PLATEAU9 ACRF2 ARM2

  17. Bench-Scale Cross Flow Filtration of

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O OLaura| National2.11DESERT * LOW HILLS * PLATEAU9 ACRF2 ARM27

  18. Bench-Scale Cross Flow Filtration of

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O OLaura| National2.11DESERT * LOW HILLS * PLATEAU9 ACRF2 ARM27

  19. Bench-Scale Cross Flow Filtration of

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O OLaura| National2.11DESERT * LOW HILLS * PLATEAU9 ACRF2

  20. Bench-Scale Cross Flow Filtration of

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O OLaura| National2.11DESERT * LOW HILLS * PLATEAU9 ACRF21

  1. Bench-Scale Cross Flow Filtration of

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O OLaura| National2.11DESERT * LOW HILLS * PLATEAU9 ACRF212

  2. Bench-Scale Cross Flow Filtration of

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O OLaura| National2.11DESERT * LOW HILLS * PLATEAU9 ACRF2123

  3. Bench-Scale Cross Flow Filtration of

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O OLaura| National2.11DESERT * LOW HILLS * PLATEAU9 ACRF21234

  4. Bench-Scale Cross Flow Filtration of

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O OLaura| National2.11DESERT * LOW HILLS * PLATEAU9 ACRF212345

  5. Bench-Scale Cross Flow Filtration of

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O OLaura| National2.11DESERT * LOW HILLS * PLATEAU9 ACRF2123456

  6. Bench-Scale Cross Flow Filtration of

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O OLaura| National2.11DESERT * LOW HILLS * PLATEAU98 ACRF

  7. Bench-Scale Cross Flow Filtration of

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O OLaura| National2.11DESERT * LOW HILLS * PLATEAU98 ACRF9

  8. Bench-Scale Cross Flow Filtration of

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O OLaura| National2.11DESERT * LOW HILLS * PLATEAU98 ACRF97

  9. Bench-Scale Cross Flow Filtration of

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O OLaura| National2.11DESERT * LOW HILLS * PLATEAU98 ACRF973

  10. Bench-Scale Cross Flow Filtration of

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O OLaura| National2.11DESERT * LOW HILLS * PLATEAU98 ACRF9738

  11. Bench-Scale Cross Flow Filtration of

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O OLaura| National2.11DESERT * LOW HILLS * PLATEAU98 ACRF97381

  12. Bench-Scale Cross Flow Filtration of

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O OLaura| National2.11DESERT * LOW HILLS * PLATEAU98 ACRF973811

  13. ARM TR-008

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsicloudden Documentation Data Management Facility009 ARM Orientation4 ACRF

  14. ARM TR-008

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsicloudden Documentation Data Management Facility009 ARM Orientation4 ACRF-018

  15. ARM TR-008

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsicloudden Documentation Data Management Facility009 ARM Orientation4 ACRF-018

  16. ARM TR-008

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsicloudden Documentation Data Management Facility009 ARM Orientation4 ACRF-0184

  17. ARM TR-008

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsicloudden Documentation Data Management Facility009 ARM Orientation4 ACRF-018410

  18. ARM TR-008

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsicloudden Documentation Data Management Facility009 ARM Orientation4 ACRF-0184101

  19. ARM TR-008

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsicloudden Documentation Data Management Facility009 ARM Orientation4 ACRF-01841015

  20. ARM TR-008

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsicloudden Documentation Data Management Facility009 ARM Orientation4 ACRF-018410159

  1. ARM TR-008

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsicloudden Documentation Data Management Facility009 ARM Orientation4 ACRF-0184101599

  2. ARM TR-008

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsicloudden Documentation Data Management Facility009 ARM Orientation4 ACRF-01841015990

  3. ARM TR-008

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsicloudden Documentation Data Management Facility009 ARM Orientation4 ACRF-0184101599045

  4. Microsoft Word - 2009-02 Instrument Report_DOE-SC-ARM-P-09.004.2.doc

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on77 PAGE OF PAGESpersonal information is revealed2 ACRF

  5. Microsoft Word - 2009O-03SystemCriteria.doc

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on77 PAGE OF PAGESpersonal information is revealed2 ACRF3

  6. Microsoft Word - 2010 06.01 FOIA for sruvelliances.docx

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on77 PAGE OF PAGESpersonal information is revealed2 ACRF3, 2010

  7. Microsoft Word - 2010 MSU_compressed with SANDno1.doc

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on77 PAGE OF PAGESpersonal information is revealed2 ACRF3,

  8. Microsoft Word - 2010-01 Instrument Report_DOE-SC-ARM-10-006.1.doc

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on77 PAGE OF PAGESpersonal information is revealed2 ACRF3,1 ARM

  9. Microsoft Word - 2010-03 Instrument Monthly_ARM_10_006.3.doc

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on77 PAGE OF PAGESpersonal information is revealed2 ACRF3,1 ARM3 ARM

  10. Microsoft Word - 2010-10-08_ESI Fact Sheet for Utilities.doc

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on77 PAGE OF PAGESpersonal information is revealed2 ACRF3,1 ARM3

  11. Microsoft Word - 2010O-01_DOE Response to Beryllium.doc

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on77 PAGE OF PAGESpersonal information is revealed2 ACRF3,1

  12. Microsoft Word - 2010O-03 DOE-RL Manager.doc

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on77 PAGE OF PAGESpersonal information is revealed2 ACRF3,1DOE-RL

  13. Microsoft Word - 2010_0204_Feb_2010_HAB_Summary_FINAL.doc

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on77 PAGE OF PAGESpersonal information is revealed2 ACRF3,1DOE-RL4-5,

  14. InGaAsP/InP intrastep quantum wells for enhanced solar energy conversion

    E-Print Network [OSTI]

    Chen, Winnie Victoria

    2012-01-01

    A low-cost, high-efficiency solar cell based on dye-well devices for high-efficiency tandem solar cells,” Solarbalance limit for solar cell efficiency (using a blackbody

  15. Investigating the presence of 500 ?m submillimeter excess emission...

    Office of Scientific and Technical Information (OSTI)

    emission with a two-temperature modified blackbody and measure excess of the 500 m photometry relative to that predicted by our model. We compare the submillimeter excess, where...

  16. Journal of Quantitative Spectroscopy & Radiative Transfer 99 (2006) 341348

    E-Print Network [OSTI]

    2006-01-01

    ). 1 Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed Martin CompanyV blackbody-like radiators [3] are presently used for inertial confinement fusion studies and other work

  17. Thermal emission measurement and calibration

    E-Print Network [OSTI]

    Brown, Susannah (Susannah R.)

    2009-01-01

    This thesis details a measurement setup and experimental procedures for emittance measurements using a Fourier transform infrared spectrometer. We calibrate the FTIR measurement system using measurements of a blackbody ...

  18. Quantum-coupled single-electron thermal to electric conversion scheme

    E-Print Network [OSTI]

    Wu, D. M.

    Thermal to electric energy conversion with thermophotovoltaics relies on radiation emitted by a hot body, which limits the power per unit area to that of a blackbody. Microgap thermophotovoltaics take advantage of evanescent ...

  19. Defects, thermal phenomena and design in photonic crystal systems

    E-Print Network [OSTI]

    Chan, David Lik Chin

    2006-01-01

    The physics of blackbodies has been an ongoing source of fascination and scientific research for over a hundred years. Kirchhoff's law states that emissivity and absorptivity are equal for an object in thermal equilibrium. ...

  20. Advanced nanofabrication of thermal emission devices

    E-Print Network [OSTI]

    Hurley, Fergus (Fergus Gerard)

    2008-01-01

    Nanofabricated thermal emission devices can be used to modify and modulate blackbody thermal radiation. There are many areas in which altering thermal radiation is extremely useful, especially in static power conversion, ...

  1. Atmospheric Radiation Measurement program climate research facility operations quarterly report January 1 - March 31, 2008.

    SciTech Connect (OSTI)

    Sisterson, D. L.

    2008-05-22

    Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998. Table 1 shows the accumulated maximum operation time (planned uptime), actual hours of operation, and variance (unplanned downtime) for the period January 1 - March 31, 2008, for the fixed sites. The AMF is being deployed to China and is not in operation this quarter. The second quarter comprises a total of 2,184 hours. The average as well as the individual site values exceeded our goal this quarter. The Site Access Request System is a web-based database used to track visitors to the fixed and mobile sites, all of which have facilities that can be visited. The NSA locale has the Barrow and Atqasuk sites. The SGP site has a central facility, 23 extended facilities, 4 boundary facilities, and 3 intermediate facilities. The TWP locale has the Manus, Nauru, and Darwin sites. FKB represents the AMF statistics for the Haselbach, Germany, past deployment in 2007. NIM represents the AMF statistics for the Niamey, Niger, Africa, past deployment in 2006. PYE represents just the AMF Archive statistics for the Point Reyes, California, past deployment in 2005. In addition, users who do not want to wait for data to be provided through the ACRF Archive can request a research account on the local site data system. The seven computers for the research accounts are located at the Barrow and Atqasuk sites; the SGP central facility; the TWP Manus, Nauru, and Darwin sites; and the DMF at PNNL. In addition, the ACRF serves as a data repository for a long-term Arctic atmospheric observatory in Eureka, Canada (80 degrees 05 minutes N, 86 degrees 43 minutes W) as part of the multiagency Study of Environmental Arctic Change (SEARCH) Program. NOAA began providing instruments for the site in 2005, and currently cloud radar data are available. The intent of the site is to monitor the important components of the Arctic atmosphere, including clouds, aerosols, atmospheric radiation, and local-scale atmospheric dynamics. Because of the similarity of ACRF NSA data streams and the important synergy that can be formed between a network of Arctic atmospheric observations, much of the SEARCH observatory data are archived in the ARM archive. Instruments will be added to the site over time. For more information, please visit http://www.db.arm.gov/data. The designation for the archived Eureka data is YEU and is now included in the ACRF user metrics. This quarterly report provides the cumulative numbers of visitors and user accounts by site for the period April 1, 2007 - March 31, 2008. Table 2 shows the summary of cumulative users for the period April 1, 2007 - March 31, 2007. For the second quarter of FY 2008, the overall number of users was nearly as high as the last reporting period, in which a new record high for number of users was established. This quarter, a new record high was established for the number of user days, particularly due to the large number of field campaign activities in conjunction with the AMF deployment in Germany, as well as major field campaigns at the NSA and SGP sites. This quarter, 37% of the Archive users are ARM science-funded principal investigators and 23% of all other facility users are either ARM science-funded principal investigators or ACRF infrastructure personnel. For reporting purposes, the three ACRF sites and the AMF operate 24 hours per day, 7 days per week, and 52 weeks per year. Time is reported in days instead of hours. I

  2. Atmospheric Radiation Measurement program climate research facility operations quarterly report July 1 - September 30, 2008.

    SciTech Connect (OSTI)

    Sisterson, D. L.

    2008-10-08

    Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998. Table 1 shows the accumulated maximum operation time (planned uptime), actual hours of operation, and variance (unplanned downtime) for the period July 1 - September 30, 2008, for the fixed sites. The AMF has been deployed to China, but the data have not yet been released. The fourth quarter comprises a total of 2,208 hours. The average exceeded our goal this quarter. The Site Access Request System is a web-based database used to track visitors to the fixed and mobile sites, all of which have facilities that can be visited. The NSA locale has the Barrow and Atqasuk sites. The SGP site has a central facility, 23 extended facilities, 4 boundary facilities, and 3 intermediate facilities. The TWP locale has the Manus, Nauru, and Darwin sites. HFE represents the AMF statistics for the Shouxian, China, deployment in 2008. FKB represents the AMF statistics for the Haselbach, Germany, past deployment in 2007. NIM represents the AMF statistics for the Niamey, Niger, Africa, past deployment in 2006. PYE represents just the AMF Archive statistics for the Point Reyes, California, past deployment in 2005. In addition, users who do not want to wait for data to be provided through the ACRF Archive can request a research account on the local site data system. The seven computers for the research accounts are located at the Barrow and Atqasuk sites; the SGP central facility; the TWP Manus, Nauru, and Darwin sites; and the DMF at PNNL. In addition, the ACRF serves as a data repository for a long-term Arctic atmospheric observatory in Eureka, Canada (80 degrees 05 minutes N, 86 degrees 43 minutes W) as part of the multiagency Study of Environmental Arctic Change (SEARCH) Program. NOAA began providing instruments for the site in 2005, and currently cloud radar data are available. The intent of the site is to monitor the important components of the Arctic atmosphere, including clouds, aerosols, atmospheric radiation, and local-scale atmospheric dynamics. Because of the similarity of ACRF NSA data streams and the important synergy that can be formed between a network of Arctic atmospheric observations, much of the SEARCH observatory data are archived in the ARM archive. Instruments will be added to the site over time. For more information, please visit http://www.db.arm.gov/data. The designation for the archived Eureka data is YEU and is now included in the ACRF user metrics. This quarterly report provides the cumulative numbers of visitors and user accounts by site for the period October 1, 2007 - September 30, 2008. Table 2 shows the summary of cumulative users for the period October 1, 2007 - September 30, 2008. For the fourth quarter of FY 2008, the overall number of users is down substantially (about 30%) from last quarter. Most of this decrease resulted from a reduction in the ACRF Infrastructure users (e.g., site visits, research accounts, on-site device accounts, etc.) associated with the AMF China deployment. While users had easy access to the previous AMF deployment in Germany that resulted in all-time high user statistics, physical and remote access to on-site accounts are extremely limited for the AMF deployment in China. Furthermore, AMF data have not yet been released from China to the Data Management Facility for processing, which affects Archive user statistics. However, Archive users are only down about 10% from last quarter. Anothe

  3. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report January 1 - March 31, 2005

    SciTech Connect (OSTI)

    DL Sisterson

    2005-03-31

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year dating back to 1998. The United States Department of Energy requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1 – (ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for this second quarter for the Southern Great Plains (SGP) site is 2052 hours (0.95 × 2,160 hours this quarter). The annual OPSMAX for the North Slope Alaska (NSA) site is 1944 hours (0.90 × 2,160), and that for the Tropical Western Pacific (TWP) site is 1836 hours (0.85 × 2,160). The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or data stream. Data availability reported here refers to the average of the individual, continuous data streams that have been received by the ACRF Archive. Data not at the Archive are caused by downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is directly related to individual instrument uptime. Thus, the average percent of data in the Archive represents the average percent of the time (24 hours per day, 90 days for this quarter) the instruments were operating this quarter.

  4. Atmospheric Radiation Measurement Program Climate Research Facility Operations Cumulative Quarterly Report October 1, 2003 - September 30, 2004

    SciTech Connect (OSTI)

    DL Sisterson

    2004-09-30

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998. The United States Department of Energy requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1 – (ACTUAL/OPSMAX)], which accounts for unplanned downtime. The annual OPSMAX time for the Southern Great Plains (SGP) site is 8,322 hours per year (0.95 × 8,760, the number hours in a year, not including leap year). The annual OPSMAX for the North Slope Alaska (NSA) site is 7,884 hours per year (0.90 × 8,760), and that for the Tropical Western Pacific (TWP) site is 7,446 hours per year (0.85 × 8,760). The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or data stream. Data availability reported here refers to the average of the individual, continuous data streams that have been received by the ACRF Archive. Data not at the Archive are caused by downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is directly related to individual instrument uptime. Thus, the average percent of data in the Archive represents the average percent of the time (24 hours per day, 365 days per year) the instruments were operating.

  5. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report April 1 - June 30, 2005

    SciTech Connect (OSTI)

    DL Sisterson

    2005-06-30

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year dating back to 1998. The United States Department of Energy requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1 – (ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for the third quarter for the Southern Great Plains (SGP) site is 2,074.8 hours (0.95 × 2,184 hours this quarter). The annual OPSMAX for the North Slope Alaska (NSA) site is 1,965.6 hours (0.90 × 2,184), and that for the Tropical Western Pacific (TWP) site is 1,856.4 hours (0.85 × 2,184). The OPSMAX time for the ARM Mobile Facility (AMF) is 2,074.8 (0.95 × 2,184). The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or data stream. Data availability reported here refers to the average of the individual, continuous data streams that have been received by the ACRF Archive. Data not at the Archive are caused by downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is directly related to individual instrument uptime. Thus, the average percent of data in the Archive represents the average percent of the time (24 hours per day, 91 days for this quarter) the instruments were operating this quarter

  6. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report October 1 - December 31, 2005

    SciTech Connect (OSTI)

    DL Sisterson

    2005-12-31

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year dating back to 1998. The U.S. Department of Energy requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1 – (ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for the third quarter for the Southern Great Plains (SGP) site is 2,097.6 hours (0.95 × 2,208 hours this quarter). The OPSMAX for the North Slope of Alaska (NSA) locale is 1,987.2 hours (0.90 × 2,208), and that for the Tropical Western Pacific (TWP) locale is 1,876.8 hours (0.85 × 2,208). The OPSMAX time for the ARM Mobile Facility (AMF) is 2,097.6 hours (0.95 × 2,208). The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or data stream. Data availability reported here refers to the average of the individual, continuous data streams that have been received by the ACRF Archive. Data not at the Archive are caused by downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is directly related to individual instrument uptime. Thus, the average percent of data in the Archive represents the average percent of the time (24 hours per day, 92 days for this quarter) the instruments were operating this quarter.

  7. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report October 1 - December 31, 2004

    SciTech Connect (OSTI)

    DL Sisterson

    2004-12-31

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year dating back to 1998. The United States Department of Energy requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1 – (ACTUAL/OPSMAX)], which accounts for unplanned downtime. The annual OPSMAX time for the Southern Great Plains (SGP) site is 8,322 hours per year (0.95 × 8,760, the number hours in a year, not including leap year). The annual OPSMAX for the North Slope Alaska (NSA) site is 7,884 hours per year (0.90 × 8,760), and that for the Tropical Western Pacific (TWP) site is 7,446 hours per year (0.85 × 8,760). The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or data stream. Data availability reported here refers to the average of the individual, continuous data streams that have been received by the ACRF Archive. Data not at the Archive are caused by downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is directly related to individual instrument uptime. Thus, the average percent of data in the Archive represents the average percent of the time (24 hours per day, 365 days per year) the instruments were operating.

  8. $\\hbar$ as a Physical Constant of Classical Optics and Electrodynamics

    E-Print Network [OSTI]

    Tremblay, Real; Allen, Claudine Ni

    2015-01-01

    The Planck constant ($\\hbar$) plays a pivotal role in quantum physics. Historically, it has been proposed as postulate, part of a genius empirical relationship $E=\\hbar \\omega$ in order to explain the intensity spectrum of the blackbody radiation for which classical electrodynamic theory led to an unacceptable prediction: The ultraviolet catastrophe. While the usefulness of the Planck constant in various fields of physics is undisputed, its derivation (or lack of) remains unsatisfactory from a fundamental point of view. In this paper, the analysis of the blackbody problem is performed with a series expansion of the electromagnetic field in terms of TE, TM modes in a metallic cavity with small losses, that leads to developing the electromagnetic fields in a \\textit{complete set of orthonormal functions}. This expansion, based on coupled power theory, maintains both space and time together enabling modeling of the blackbody's evolution toward equilibrium. Reaching equilibrium with a multimodal waveguide analysi...

  9. Photon-conserving Comptonization in simulations of accretion disks around black holes

    E-Print Network [OSTI]

    Sadowski, Aleksander

    2015-01-01

    We introduce a new method for treating Comptonization in computational fluid dynamics. By construction, this method conserves the number of photons. Whereas the traditional "blackbody Comptonization" approach assumes that the radiation is locally a perfect blackbody and therefore uses a single parameter, the radiation temperature, to describe the radiation, the new "photon-conserving Comptonization" approach treats the photon gas as a Bose-Einstein fluid and keeps track of both the radiation temperature and the photon number density. We have implemented photon-conserving Comptonization in the general relativistic radiation magnetohydrodynamical code KORAL and we describe its impact on simulations of mildly super-critical black hole accretion disks. We find that blackbody Comptonization underestimates the gas and radiation temperature by up to a factor of two compared to photon-conserving Comptonization. This discrepancy could be serious when computing spectra. The photon-conserving simulation indicates that t...

  10. Photon Clusters in Thermal Radiation

    E-Print Network [OSTI]

    Aleksey Ilyin

    2014-10-30

    Within the framework of Bose-Einstein statistics, it is shown that the blackbody radiation, in addition to single photons, contains photon clusters, or coalescent photons. The probability to find a k-photon cluster versus radiation frequency and temperature is found, as well as the statistics of clusters. Spectra of photon-cluster radiation are calculated as functions of blackbody temperature. The Planck's radiation law is derived based on the existence of photon clusters. The possibility of experimental observation of photon clusters in thermal radiation is discussed.

  11. Some remarks on black hole thermodynamics

    E-Print Network [OSTI]

    R. Y. Chiao

    2011-02-04

    Two thermodynamic "paradoxes" of black hole physics are re-examined. The first is that there is a thermal instability involving two coupled blackbody cavities containing two black holes, and second is that a classical black hole can swallow up entropy in the form of ambient blackbody photons without increasing its mass. The resolution of the second paradox by Bekenstein and by Hawking is re-visited. The link between Hawking radiation and Wigner's superluminal tunneling time is discussed using two equivalent Feynman diagrams, and Feynman's re-interpretation principle.

  12. Cloud Occurrence Frequency at the Barrow, Alaska, ARM Climate Research Facility for 2008 Third Quarter 2009 ARM and Climate Change Prediction Program Metric Report

    SciTech Connect (OSTI)

    M Jensen; K Johnson; JH Mather

    2009-07-14

    Clouds represent a critical component of the Earth’s atmospheric energy balance as a result of their interactions with solar and terrestrial radiation and a redistribution of heat through convective processes and latent heating. Despite their importance, clouds and the processes that control their development, evolution and lifecycle remain poorly understood. Consequently, the simulation of clouds and their associated feedbacks is a primary source of inter-model differences in equilibrium climate sensitivity. An important step in improving the representation of cloud process simulations is an improved high-resolution observational data set of the cloud systems including their time evolution. The first order quantity needed to understand the important role of clouds is the height of cloud occurrence and how it changes as a function of time. To this end, the Atmospheric Radiation Measurement (ARM) Climate Research Facilities (ACRF) suite of instrumentation has been developed to make the observations required to improve the representation of cloud systems in atmospheric models.

  13. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report July 1 - September 30, 2007

    SciTech Connect (OSTI)

    DL Sisterson

    2007-10-01

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ARM Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.

  14. Contributions of the Atmospheric Radiation Measurement (ARM) Program and the ARM Climate Research Facility to the U.S. Climate Change Science Program

    SciTech Connect (OSTI)

    SA Edgerton; LR Roeder

    2008-09-30

    The Earth’s surface temperature is determined by the balance between incoming solar radiation and thermal (or infrared) radiation emitted by the Earth back to space. Changes in atmospheric composition, including greenhouse gases, clouds, and aerosols can alter this balance and produce significant climate change. Global climate models (GCMs) are the primary tool for quantifying future climate change; however, there remain significant uncertainties in the GCM treatment of clouds, aerosol, and their effects on the Earth’s energy balance. The 2007 assessment (AR4) by the Intergovernmental Panel on Climate Change (IPCC) reports a substantial range among GCMs in climate sensitivity to greenhouse gas emissions. The largest contributor to this range lies in how different models handle changes in the way clouds absorb or reflect radiative energy in a changing climate (Solomon et al. 2007). In 1989, the U.S. Department of Energy (DOE) Office of Science created the Atmospheric Radiation Measurement (ARM) Program within the Office of Biological and Environmental Research (BER) to address scientific uncertainties related to global climate change, with a specific focus on the crucial role of clouds and their influence on the transfer of radiation in the atmosphere. To address this problem, BER has adopted a unique two-pronged approach: * The ARM Climate Research Facility (ACRF), a scientific user facility for obtaining long-term measurements of radiative fluxes, cloud and aerosol properties, and related atmospheric characteristics in diverse climate regimes. * The ARM Science Program, focused on the analysis of ACRF data to address climate science issues associated with clouds, aerosols, and radiation, and to improve GCMs. This report describes accomplishments of the BER ARM Program toward addressing the primary uncertainties related to climate change prediction as identified by the IPCC.

  15. A Climatology of Fair-Weather Cloud Statistics at the Atmospheric Radiation Measurement Program Southern Great Plains Site: Temporal and Spatial Variability

    SciTech Connect (OSTI)

    Berg, Larry K.; Kassianov, Evgueni I.; Long, Charles N.; Gustafson, William I.

    2006-03-30

    In previous work, Berg and Stull (2005) developed a new parameterization for Fair-Weather Cumuli (FWC). Preliminary testing of the new scheme used data collected during a field experiment conducted during the summer of 1996. This campaign included a few research flights conducted over three locations within the Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) Southern Great Plains (SGP) site. A more comprehensive verification of the new scheme requires a detailed climatology of FWC. Several cloud climatologies have been completed for the ACRF SGP, but these efforts have focused on either broad categories of clouds grouped by height and season (e.g., Lazarus et al. 1999) or height and time of day (e.g., Dong et al. 2005). In these two examples, the low clouds were not separated by the type of cloud, either stratiform or cumuliform, nor were the horizontal chord length (the length of the cloud slice that passed directly overhead) or cloud aspect ratio (defined as the ratio of the cloud thickness to the cloud chord length) reported. Lane et al. (2002) presented distributions of cloud chord length, but only for one year. The work presented here addresses these shortcomings by looking explicitly at cases with FWC over five summers. Specifically, we will address the following questions: •Does the cloud fraction (CF), cloud-base height (CBH), and cloud-top height (CTH) of FWC change with the time of day or the year? •What is the distribution of FWC chord lengths? •Is there a relationship between the cloud chord length and the cloud thickness?

  16. Atmospheric Radiation Measurement program climate research facility operations quarterly report October 1 - December 31, 2007.

    SciTech Connect (OSTI)

    Sisterson, D. L.

    2008-01-24

    Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998. Table 1 shows the accumulated maximum operation time (planned uptime), actual hours of operation, and variance (unplanned downtime) for the period October 1 - December 31, 2007, for the fixed sites and the mobile site. The AMF has been deployed to Germany and this was the final operational quarter. The first quarter comprises a total of 2,208 hours. Although the average exceeded our goal this quarter, a series of severe weather events (i.e., widespread ice storms) disrupted utility services, which affected the SGP performance measures. Some instruments were covered in ice and power and data communication lines were down for more than 10 days in some areas of Oklahoma and Kansas, which resulted in lost data at the SGP site. The Site Access Request System is a web-based database used to track visitors to the fixed sites, all of which have facilities that can be visited. The NSA locale has the Barrow and Atqasuk sites. The SGP site has a central facility, 23 extended facilities, 4 boundary facilities, and 3 intermediate facilities. The TWP locale has the Manus, Nauru, and Darwin sites. The AMF completed its mission at the end of this quarter in Haselback, Germany (FKB designation). NIM represents the AMF statistics for the Niamey, Niger, Africa, past deployment in 2006. PYE represents just the AMF Archive statistics for the Point Reyes, California, past deployment in 2005. In addition, users who do not want to wait for data to be provided through the ACRF Archive can request an account on the local site data system. The eight research computers are located at the Barrow and Atqasuk sites; the SGP central facility; the TWP Manus, Nauru, and Darwin sites; the DMF at PNNL; and the AMF, currently in Germany. In addition, the ACRF serves as a data repository for a long-term Arctic atmospheric observatory in Eureka, Canada (80 degrees 05 minutes N, 86 degrees 43 minutes W) as part of the multiagency Study of Environmental Arctic Change (SEARCH) Program. NOAA began providing instruments for the site in 2005, and currently cloud radar data are available. The intent of the site is to monitor the important components of the Arctic atmosphere, including clouds, aerosols, atmospheric radiation, and local-scale atmospheric dynamics. Due to the similarity of ACRF NSA data streams, and the important synergy that can be formed between a network of Arctic atmospheric observations, much of the SEARCH observatory data are archived in the ARM archive. Instruments will be added to the site over time. For more information, please visit http://www.db.arm.gov/data. The designation for the archived Eureka data is YEU and is now included in the ACRF user metrics. This quarterly report provides the cumulative numbers of visitors and user accounts by site for the period January 1, 2007 - December 31, 2007. Table 2 shows the summary of cumulative users for the period January 1, 2007 - December 31, 2007. For the first quarter of FY 2008, the overall number of users was up significantly from the last reporting period. For the fourth consecutive reporting period, a record high number of Archive users was recorded. In addition, the number of visitors and visitor days set a new record this reporting period particularly due to the large number of field campaign activities in conjunction with the AMF deployment in Germany. It is interesting to note this quarter that

  17. Broadband Outdoor Radiometer Calibration Process for the Atmospheric Radiation Measurement Program

    SciTech Connect (OSTI)

    Dooraghi, Michael

    2015-09-01

    The Atmospheric Radiation Measurement program (ARM) maintains a fleet of monitoring stations to aid in the improved scientific understanding of the basic physics related to radiative feedback processes in the atmosphere, particularly the interactions among clouds and aerosols. ARM obtains continuous measurements and conducts field campaigns to provide data products that aid in the improvement and further development of climate models. All of the measurement campaigns include a suite of solar measurements. The Solar Radiation Research Laboratory at the National Renewable Energy Laboratory supports ARM's full suite of stations in a number of ways, including troubleshooting issues that arise as part of the data-quality reviews; managing engineering changes to the standard setup; and providing calibration services and assistance to the full fleet of solar-related instruments, including pyranometers, pyrgeometers, pyrheliometers, as well as the temperature/relative humidity probes, multimeters, and data acquisition systems that are used in the calibrations performed at the Southern Great Plains Radiometer Calibration Facility. This paper discusses all aspects related to the support provided to the calibration of the instruments in the solar monitoring fleet.

  18. PUBLISHED ONLINE: 30 MAY 2010 | DOI: 10.1038/NPHYS1680 Thermalization of a two-dimensional photonic

    E-Print Network [OSTI]

    Loss, Daniel

    -dimensional photonic gas in a `white wall' photon box Jan Klaers, Frank Vewinger and Martin Weitz* Bose­Einstein of a bosonic gas, blackbody radiation9 , however exhibits no Bose­Einstein condensation at low temperatures10 mirrors provide both an effective photon mass and a confining potential--key prerequisites for the Bose­Einstein

  19. Magnetic Mirrors at the Nanoscale : Theory M. P. J. L. Chang, D. Jia1 and H. Nazari2

    E-Print Network [OSTI]

    Chang, Mark J. L.

    of heat from one wire coil to the defect will be higher than the rate due to uniform blackbody radiation. In the case of tungsten, for our typical spiral geometry, the heating rate is enhanced by a factor of 15 as 106 , which is evidently not appropriate. Keywords: Magnetic Mirrors, Vector Potential, Radiative Heat

  20. 178 Bishop's University 2015/2016 EVL 242 Environmental Chemistry Laboratory 1-0-4

    E-Print Network [OSTI]

    : the greenhouse effect, blackbody radiation, the ozone problem, mathematical techniques, heat transfer-based, course discusses fundamental environmental problems within a physical context. Topics covered include, a language which allows scientists to quantify, model, understand and predict be- haviour in an enormously

  1. arXiv:astro-ph/0304219v111Apr2003 ACCEPTED BY THE ASTROPHYSICAL JOURNAL Preprint typeset using LATEX style emulateapj v. 04/03/99

    E-Print Network [OSTI]

    Kalemci, Emrah

    also compare the flares to X-ray bursts that are seen in neutron star systems. While some of the flare as evidence that a given system contains a neutron star unless the presence of a blackbody component first, and currently only, outburst. By monitoring the source at low luminosities over several months

  2. SPECTRAL SOLAR IRRADIANCE AND ITS ENTROPIC EFFECT ON EARTH'S CLIMATE

    E-Print Network [OSTI]

    comparison with a conventional approach by using a blackbody Sun's brightness temperature exhibits Experiment (SORCE) satellite are used to examine the magnitude and spectral distribution of the Earth radiation received at the top of the atmosphere (TOA) is the same as that radiated at the Sun's surface

  3. Deep ultraviolet photodetectors grown by gas source molecular beam epitaxy on sapphire and AlGaN/sapphire substrates

    E-Print Network [OSTI]

    Holtz, Mark

    , CINVESTAV, Mexico D.F. 07300, Mexico ABSTRACT Optically-based chemical and biological sensors require: photodetector, solar blind, AlGaN, superlattice 1. INTRODUCTION A solar blind photodetector (SBPD) is sensitive the solar blackbody spectrum [1]. Such photodetectors have broad applications including space

  4. Comptonization signatures in the prompt emission of gamma-ray bursts

    SciTech Connect (OSTI)

    Frontera, F.; Farinelli, R.; Dichiara, S.; Guidorzi, C.; Titarchuk, L. [Dipartimento di Fisicae Scienze della Terra, Università di Ferrara, Via Saragat 1, I-44100 Ferrara (Italy); Amati, L.; Landi, R., E-mail: frontera@fe.infn.it [INAF, Istituto di Astrofisica Spaziale e Fisica Cosmica, Bologna, Via Gobetti 101, I-40129 Bologna (Italy)

    2013-12-20

    We report results of a systematic study of the broadband (2-2000 keV) time-resolved prompt emission spectra of a sample of gamma-ray bursts (GRBs) detected with both Wide Field Cameras (WFCs) on board the BeppoSAX satellite and the Burst and Transient Source Experiment (BATSE) on board the Compton Gamma Ray Observatory. The main goal of this paper is to test spectral models of the GRB prompt emission that have recently been proposed. In particular, we test a recent photospheric model proposed, i.e., blackbody plus power law, the addition of a blackbody emission to the Band function in the cases in which this function does not fit the data, and a recent Comptonization model. By considering the few spectra for which the simple Band function does not provide a fully acceptable fit to the data, we find a statistically significant better fit by adding a blackbody to this function only in one case. We confirm earlier results found fitting the BATSE spectra alone with a blackbody plus power law. Instead, when the BATSE GRB spectra are joined to those obtained with WFCs (2-28 keV), this model becomes unacceptable in most time intervals in which we subdivide the GRB light curves. We find instead that the Comptonization model is always acceptable, even in the few cases in which the Band function is inconsistent with the data. We discuss the implications of these results.

  5. Physics 143a: Quantum Mechanics I Spring 2015, Harvard Here is a summary of the most important points from the first lecture (with a few of my own tidbits),

    E-Print Network [OSTI]

    in SI units, which are chosen to be "close to 1" on everyday, human-size objects. Quantum mechanics. We usually work with = h 2 . (2) The development of quantum mechanics was motivated by experiments that the energy of the radiation emitted by this blackbody would be infinite. Planck (curve fitting) and Einstein

  6. Physics 143a: Quantum Mechanics I Spring 2015, Harvard Here is a summary of the most important points from the first lecture (with a few of my own tidbits),

    E-Print Network [OSTI]

    ) It is very small in SI units, which are chosen to be "close to 1" on everyday, human-size objects. Quantum by experiments (discussed below). The theory gluing everything together came 20 years later. Remarkably, Schr that the energy of the radiation emitted by this blackbody would be infinite. Planck (curve fitting) and Einstein

  7. An External Shock Origin of GRB $\\textit{141028A}$

    E-Print Network [OSTI]

    Burgess, J Michael; Ryde, Felix; Omodei, Nicola; Pe'er, Asaf; Racusin, J L; Cucchiara, A

    2015-01-01

    The prompt emission of the long, smooth, and single-pulsed gamma-ray burst, GRB $\\textit{141028A}$, is analyzed under the guise of an external shock model. First, we fit the $\\gamma$-ray spectrum with a two-component photon model, namely synchrotron+blackbody, and then fit the recovered evolution of the synchrotron $\

  8. How we know that photons are bosons: experimental tests of spin-statistics for photons

    E-Print Network [OSTI]

    Budker, Dmitry

    : deviations from the Planck blackbody spectrum; non-standard behavior at large single- mode occupation number (i.e., a soft upper bound on the single-mode occupation number N) were suggested to exist,4-standard behavior of quons at high N has been reported, and the situation with regards to such behavior is thus

  9. Last Latexed: February 24, 2005 at 14:08 1 Physics 228, Lecture 11

    E-Print Network [OSTI]

    Coleman, Piers

    with the Planck blackbody explanation) that a coherent theory of quantum mechanics devel- oped. And as that theory electromagnetic radiation that the accelerating electron ought to be producing. The allowed orbits are those spectrum completely, including cal- culating the Rydberg constant in terms of fundamental constants! When

  10. PHYSICAL REVIEW B 85, 155422 (2012) Near-field thermal radiation transfer controlled by plasmons in graphene

    E-Print Network [OSTI]

    2012-01-01

    -field radiation transfer between two closely separated graphene sheets. The dependence of near-field heat exchange blackbodies in the far field. In general, the radiative heat transfer between two bodies at temperatures T1PHYSICAL REVIEW B 85, 155422 (2012) Near-field thermal radiation transfer controlled by plasmons

  11. Near-Field Radiative Heat Transfer between Macroscopic Planar Surfaces R. S. Ottens,1

    E-Print Network [OSTI]

    Tanner, David B.

    Near-Field Radiative Heat Transfer between Macroscopic Planar Surfaces R. S. Ottens,1 V. Quetschke-field, blackbody radiation. Although heat transfer via near-field effects has been discussed for many years.014301 PACS numbers: 44.40.+a, 78.20.Ci Humans knew of radiative heat transfer at least as early

  12. 15.1 Preliminaries: Wave Motion and Light 15.2 Experimental Basis of Energy Quantization

    E-Print Network [OSTI]

    Ihee, Hyotcherl

    #12;15.1 Preliminaries: Wave Motion and Light #12;#12;#12;15.2 Experimental Basis of Energy the radical concept of energy quantization to explain two of these results. #12;Blackbody Radiation · Every object emits energy through thermal radiation from its surface. · This energy is carried

  13. THERMAL RADIATION SUMMARY (Rees Chapter 2)

    E-Print Network [OSTI]

    Sandwell, David T.

    words this approximation is good when viewing thermal emissions from the Earth over the microwave band. Microwave radiometers can measure the power received L at an antenna. This is sometimes called). Solar radiation at the top of the atmosphere is well approximated by a blackbody spectrum (yellow

  14. Light production metrics of radiation sources

    E-Print Network [OSTI]

    C. Tannous

    2013-11-14

    Light production by a radiation source is evaluated and reviewed as an important concept of physics from the Black-Body point of view. The mechanical equivalent of the lumen, the unit of perceived light, is explained and evaluated using radiation physics arguments. The existence of an upper limit of luminous efficacy is illustrated for various sources and implications are highlighted.

  15. April 15, 2004 / Vol. 29, No. 8 / OPTICS LETTERS 863 Design and optimization of one-dimensional photonic crystals

    E-Print Network [OSTI]

    Perreault, Dave

    the emitter to the diode, which is function of the frequency v, the angle of incidence u (as shown in Fig. 1 lected back to the emitter by the back-side contact. In this Let- ter we investigate the performance the blackbody source at temperature TBB to the PV diode can be cal- culated using an ideal thermodynamic model1

  16. Time-resolved analysis of Fermi gamma-ray bursts with fast- and slow-cooled synchrotron photon models

    SciTech Connect (OSTI)

    Burgess, J. M.; Preece, R. D.; Connaughton, V.; Briggs, M. S.; Goldstein, A.; Bhat, P. N.; Paciesas, W. S.; Xiong, S. [University of Alabama in Huntsville, 320 Sparkman Drive, Huntsville, AL 35899 (United States); Greiner, J.; Gruber, D.; Kienlin, A.; Rau, A. [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching (Germany); Kouveliotou, C. [Space Science Office, VP62, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States); McGlynn, S. [Exzellence Cluster "Universe," Technische Universitt Mnchen, Boltzmannstrasse 2, D-85748, Garching (Germany); Meegan, C. A. [Universities Space Research Association, 320 Sparkman Drive, Huntsville, AL 35899 (United States); Axelsson, M. [Department of Astronomy, Stockholm University, SE-106 91 Stockholm (Sweden); Baring, M. G. [Rice University, Department of Physics and Astronomy, MS-108, P.O. Box 1892, Houston, TX 77251 (United States); Dermer, C. D. [Space Science Division, Naval Research Laboratory, Washington, DC 20375-5352 (United States); Iyyani, S. [The Oskar Klein Centre for Cosmoparticle Physics, AlbaNova, SE-106 91 Stockholm (Sweden); Kocevski, D., E-mail: james.m.burgess@nasa.gov, E-mail: Rob.Preece@nasa.gov, E-mail: shabuiyyani@gmail.com, E-mail: baring@rice.edu [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics, and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); and others

    2014-03-20

    Time-resolved spectroscopy is performed on eight bright, long gamma-ray bursts (GRBs) dominated by single emission pulses that were observed with the Fermi Gamma-Ray Space Telescope. Fitting the prompt radiation of GRBs by empirical spectral forms such as the Band function leads to ambiguous conclusions about the physical model for the prompt radiation. Moreover, the Band function is often inadequate to fit the data. The GRB spectrum is therefore modeled with two emission components consisting of optically thin non-thermal synchrotron radiation from relativistic electrons and, when significant, thermal emission from a jet photosphere, which is represented by a blackbody spectrum. To produce an acceptable fit, the addition of a blackbody component is required in five out of the eight cases. We also find that the low-energy spectral index ? is consistent with a synchrotron component with ? = –0.81 ± 0.1. This value lies between the limiting values of ? = –2/3 and ? = –3/2 for electrons in the slow- and fast-cooling regimes, respectively, suggesting ongoing acceleration at the emission site. The blackbody component can be more significant when using a physical synchrotron model instead of the Band function, illustrating that the Band function does not serve as a good proxy for a non-thermal synchrotron emission component. The temperature and characteristic emission-region size of the blackbody component are found to, respectively, decrease and increase as power laws with time during the prompt phase. In addition, we find that the blackbody and non-thermal components have separate temporal behaviors as far as their respective flux and spectral evolutions.

  17. Informal Preliminary Report on Comparisons of Prototype SPN-1 Radiometer to PARSL Measurements

    SciTech Connect (OSTI)

    Long, Charles N.

    2014-06-17

    The prototype SPN-1 has been taking measurements for several months collocated with our PNNL Atmospheric Remote Sensing Laboratory (PARSL) solar tracker mounted instruments at the Pacific Northwest National Laboratory (PNNL) located in Richland, Washington, USA. The PARSL radiometers used in the following comparisons consist of an Eppley Normal Incident Pyrheliometer (NIP) and a shaded Eppley model 8-48 “Black and White” pyrgeometer (B&W) to measure the direct and diffuse shortwave irradiance (SW), respectively. These instruments were calibrated in mid-September by comparison to an absolute cavity radiometer directly traceable to the world standard group in Davos, Switzerland. The NIP calibration was determined by direct comparison, while the B&W was calibrated using the shade/unshade technique. All PARSL data prior to mid-September have been reprocessed using the new calibration factors. The PARSL data are logged as 1-minute averages from 1-second samples. Data used in this report span the time period from June 22 through December 1, 2006. All data have been processed through the QCRad code (Long and Shi, 2006), which itself is a more elaborately developed methodology along the lines of that applied by the Baseline Surface Radiation Network (BSRN) Archive (Long and Dutton, 2004), for quality control. The SPN-1 data are the standard total and diffuse SW values obtained from the analog data port of the instrument. The comparisons use only times when both the PARSL and SPN-1 data passed all QC testing. The data were further processed and analyzed by application of the SW Flux Analysis methodology (Long and Ackerman, 2000; Long and Gaustad, 2004, Long et al., 2006) to detect periods of clear skies, calculate continuous estimates of clear-sky SW irradiance and the effect of clouds on the downwelling SW, and estimate fractional sky cover.

  18. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report July 1 – September 30, 2008

    SciTech Connect (OSTI)

    DL Sisterson

    2008-09-30

    Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998. The U.S. Department of Energy (DOE) requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1 – (ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for the fourth quarter of FY 2008 for the Southern Great Plains (SGP) site is 2,097.60 hours (0.95 ? 2,208 hours this quarter). The OPSMAX for the North Slope Alaska (NSA) locale is 1,987.20 hours (0.90 ? 2,208), and for the Tropical Western Pacific (TWP) locale is 1,876.80 hours (0.85 ? 2,208). The OPSMAX time for the ARM Mobile Facility (AMF) is not reported this quarter because the data have not yet been released from China to the DMF for processing. The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or data stream. Data availability reported here refers to the average of the individual, continuous data streams that have been received by the Archive. Data not at the Archive are caused by downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is directly related to individual instrument uptime. Thus, the average percentage of data in the Archive represents the average percentage of the time (24 hours per day, 92 days for this quarter) the instruments were operating this quarter.

  19. Atmospheric Radiation Measurement program climate research facility operations quarterly report October 1 - December 31, 2008.

    SciTech Connect (OSTI)

    Sisterson, D. L.

    2009-01-15

    Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, they calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998. The US Department of Energy (DOE) requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1-(ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for the first quarter of FY 2009 for the Southern Great Plains (SGP) site is 2,097.60 hours (0.95 x 2,208 hours this quarter). The OPSMAX for the North Slope Alaska (NSA) locale is 1,987.20 hours (0.90 x 2,208), and for the Tropical Western Pacific (TWP) locale is 1,876.80 hours (0.85 x 2,208). The OPSMAX time for the ARM Mobile Facility (AMF) is not reported this quarter because the data have not yet been released from China to the DMF for processing. The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or data stream. Data availability reported here refers to the average of the individual, continuous data streams that have been received by the Archive. Data not at the Archive are caused by downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is directly related to individual instrument uptime. Thus, the average percentage of data in the Archive represents the average percentage of the time (24 hours per day, 92 days for this quarter) the instruments were operating this quarter. Table 1 shows the accumulated maximum operation time (planned uptime), actual hours of operation, and variance (unplanned downtime) for the period October 1-December 31, 2008, for the fixed sites. The AMF has been deployed to China, but the data have not yet been released. The first quarter comprises a total of 2,208 hours. The average exceeded their goal this quarter.

  20. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report January-March 2006

    SciTech Connect (OSTI)

    DL Sisterson

    2006-03-31

    Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year; and (2) site and fiscal year dating back to 1998. The U.S. Department of Energy requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1 – (ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for the second quarter for the Southern Great Plains (SGP) site is 2,052 hours (0.95 × 2,160 hours this quarter). The OPSMAX for the North Slope Alaska (NSA) locale is 1,944 hours (0.90 × 2,160), and that for the Tropical Western Pacific (TWP) locale is 1,836 hours (0.85 × 2,160). The OPSMAX time for the ARM Mobile Facility (AMF) is 2,052 hours (0.95 × 2,160). The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or data stream. Data availability reported here refers to the average of the individual, continuous data streams that have been received by the Archive. Data not at the Archive are caused by downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is directly related to individual instrument uptime. Thus, the average percent of data in the Archive represents the average percent of the time (24 hours per day, 90 days for this quarter) the instruments were operating this quarter.

  1. Redshifting of cosmological black bodies in BSBM varying-alpha theories

    E-Print Network [OSTI]

    John D. Barrow; Joao Magueijo

    2014-11-03

    We analyse the behaviour of black-body radiation in theories of electromagnetism which allow the electron charge and the fine structure constant to vary in space and time. We show that such theories can be expressed as relativistic generalizations of a conventional dielectric. By making the appropriate definition of the vector potential and associated gauge transformations, we can identify the equivalent of the electric and displacement fields, $\\mathbf{E}$ and $\\mathbf{D}$, as well as the magnetic $ \\mathbf{B}$ and $\\mathbf{H}$ fields. We study the impact of such dielectrics on the propagation of light in the so-called BSBM theory and conclude that no changes are created to the standard cosmological evolution of the temperature and energy-density of black-body radiation.

  2. A Critical Analysis of Universality and Kirchhoff's Law: A Return to Stewart's Law of Thermal Emission

    E-Print Network [OSTI]

    Pierre-Marie Robitaille

    2008-05-12

    It has been advanced, on experimental (P.-M. Robitaille, IEEE Trans. Plasma Sci. 2003, v. 31(6), 1263-1267) and theoretical (P.M. Robitaille, Progr. Phys. 2006, v.2, 22-23) grounds, that blackbody radiation is not universal and remains closely linked to the emission of graphite and soot. In order to strengthen such claims, a conceptual analysis of the proofs for universality is presented. This treatment reveals that Gustav Robert Kirchhoff has not properly considered the combined effects of absorption, reflection, and the directional nature of emission in real materials. In one instance, this leads to an unintended movement away from thermal equilibrium within cavities. Using equilibrium arguments, it is demonstrated that the radiation within perfectly reflecting or arbitrary cavities does not necessarily correspond to that emitted by a blackbody.

  3. On burning a lump of coal

    E-Print Network [OSTI]

    Ana Alonso-Serrano; Matt Visser

    2015-11-03

    Burning something, (e.g. the proverbial lump of coal, or an encyclopaedia for that matter), in a blackbody furnace leads to an approximately Planck emission spectrum with an average entropy/information transfer of approximately $3.9 \\pm 2.5$ bits per emitted photon. This quantitative and qualitative result depends only on the underlying unitarity of the quantum physics of burning, combined with the statistical mechanics of blackbody radiation. The fact that the utterly standard and unitarity preserving process of burning something (in fact, burning anything) nevertheless *has* an associated entropy/information budget, and the quantitative *size* of that entropy/information budget, is a severely under-appreciated feature of standard quantum statistical physics.

  4. On burning a lump of coal

    E-Print Network [OSTI]

    Alonso-Serrano, Ana

    2015-01-01

    Burning something, (e.g. the proverbial lump of coal, or an encyclopaedia for that matter), in a blackbody furnace leads to an approximately Planck emission spectrum with an average entropy/information transfer of approximately $3.9 \\pm 2.5$ bits per emitted photon. This quantitative and qualitative result depends only on the underlying unitarity of the quantum physics of burning, combined with the statistical mechanics of blackbody radiation. The fact that the utterly standard and unitarity preserving process of burning something (in fact, burning anything) nevertheless *has* an associated entropy/information budget, and the quantitative *size* of that entropy/information budget, is a severely under-appreciated feature of standard quantum statistical physics.

  5. High speed infrared radiation thermometer, system, and method

    DOE Patents [OSTI]

    Markham, James R. (Middlefield, CT)

    2002-01-01

    The high-speed radiation thermometer has an infrared measurement wavelength band that is matched to the infrared wavelength band of near-blackbody emittance of ceramic components and ceramic thermal barrier coatings used in turbine engines. It is comprised of a long wavelength infrared detector, a signal amplifier, an analog-to-digital converter, an optical system to collect radiation from the target, an optical filter, and an integral reference signal to maintain a calibrated response. A megahertz range electronic data acquisition system is connected to the radiation detector to operate on raw data obtained. Because the thermometer operates optimally at 8 to 12 .mu.m, where emittance is near-blackbody for ceramics, interferences to measurements performed in turbine engines are minimized. The method and apparatus are optimized to enable mapping of surface temperatures on fast moving ceramic elements, and the thermometer can provide microsecond response, with inherent self-diagnostic and calibration-correction features.

  6. Thermality of the Hawking flux

    E-Print Network [OSTI]

    Visser, Matt

    2014-01-01

    Is the Hawking flux "thermal"? Unfortunately, the answer to this seemingly innocent question depends on a number of often unstated, but quite crucial, technical assumptions built into modern (mis-)interpretations of the word "thermal". The original 1850's notions of thermality --- based on classical thermodynamic reasoning applied to idealized "black bodies" or "lamp black surfaces" --- when supplemented by specific basic quantum ideas from the early 1900's, immediately led to the notion of the black-body spectrum, (the Planck-shaped spectrum), but "without" any specific assumptions or conclusions regarding correlations between the quanta. Many (not all) modern authors (often implicitly and unintentionally) add an extra, and quite unnecessary, assumption that there are no correlations in the black-body radiation; but such usage is profoundly ahistorical and dangerously misleading. Specifically, the Hawking flux from an evaporating black hole, (just like the radiation flux from a leaky furnace or a burning lum...

  7. Modeling, image processing and attitude estimation of high speed star sensors 

    E-Print Network [OSTI]

    Katake, Anup Bharat

    2009-05-15

    Plate 350nm or longer MgF2 115nm or longer Borosilicate Glass 300nm or longer detector. The transmittance of the material is also dependent on the wavelength of the incident radiation. Table II lists some of the available materials and their spectral... . . . . . . . . . . . . . . . . . . . . 167 a. Visual and Apparent Magnitudes . . . . . . . . . 168 2. Spectral Classification of Stars . . . . . . . . . . . . . 169 3. Stars as Blackbody Radiators . . . . . . . . . . . . . . 170 C. Generation of On-board Star Catalogs...

  8. On an Improvement of the Planck radiation Energy Distribution

    E-Print Network [OSTI]

    Diego Saa

    2006-07-18

    The probability distribution function for thermodynamics and econophysics is obtained by solving an equilibrium equation. This approach is different from the common one of optimizing the entropy of the system or obtaining the state of maximum probability, which usually obtains as a result the Boltzmann distribution. The Gamma distribution is proposed as a better equation to describe the blackbody radiation in substitution of Planck's radiation equation. Also, a new form of entropy is proposed, that maintains the correct relation with the Clausius' formula.

  9. Supplementary Material The Open Atmospheric Science Journal, 2008, Volume 2 i Supplementary Material

    E-Print Network [OSTI]

    Royer, Dana

    the sun, which is ~240 W/m2 . A blackbody temperature of ~255°K yields a heat flux of 240 W/m2 . Indeed in the calculated 3.5 W/m2 forcing due to surface changes (ice sheet area, vegetation distribution, shoreline with that approach is that, unlike long-lived GHGs, aerosols are distributed heterogeneously, so it is difficult

  10. Numerical simulations of stripping effects in high-intensity hydrogen ion linacs

    SciTech Connect (OSTI)

    Carneiro, J.-P.; Mustapha, B.; Ostroumov, P.N.; /Argonne

    2008-12-01

    Numerical simulations of H{sup -} stripping losses from blackbody radiation, electromagnetic fields, and residual gas have been implemented into the beam dynamics code TRACK. Estimates of the stripping losses along two high-intensity H{sup -} linacs are presented: the Spallation Neutron Source linac currently being operated at Oak Ridge National Laboratory and an 8 GeV superconducting linac currently being designed at Fermi National Accelerator Laboratory.

  11. On parton distributions in a photon gas

    E-Print Network [OSTI]

    I. Alikhanov

    2009-06-19

    In some cases it may be useful to know parton distributions in a photon gas. This may be relevant, e.g., for the analysis of interactions of high energy cosmic ray particles with the cosmic microwave background radiation. The latter can be considered as a gas of photons with an almost perfect blackbody spectrum. An approach to finding such parton distributions is described. The survival probability of ultra-high energy neutrinos traveling through this radiation is calculated.

  12. BROADBAND SPECTRAL INVESTIGATIONS OF SGR J1550-5418 BURSTS

    SciTech Connect (OSTI)

    Lin Lin; Goegues, Ersin; Kaneko, Yuki [Faculty of Engineering and Natural Sciences, Sabanc Latin-Small-Letter-Dotless-I University, Orhanl Latin-Small-Letter-Dotless-I Tuzla, Istanbul 34956 (Turkey); Baring, Matthew G. [Department of Physics and Astronomy, Rice University, MS-108, P.O. Box 1892, Houston, TX 77251 (United States); Granot, Jonathan [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Kouveliotou, Chryssa [Space Science Office, VP62, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States); Van der Horst, Alexander; Watts, Anna L. [Astronomical Institute 'Anton Pannekoek', University of Amsterdam, Postbus 94249, 1090 GE Amsterdam (Netherlands); Gruber, David; Von Kienlin, Andreas [Max-Planck-Institut fuer extraterrestrische Physik, Postfach 1312, D-85748 Garching bei Mnchen (Germany); Younes, George [USRA, National Space Science and Technology Center, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Gehrels, Neil, E-mail: linlin@sabanciuniv.edu [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2012-09-01

    We present the results of our broadband spectral analysis of 42 SGR J1550-5418 bursts simultaneously detected with the Swift/X-ray Telescope (XRT) and the Fermi/Gamma-ray Burst Monitor (GBM), during the 2009 January active episode of the source. The unique spectral and temporal capabilities of the XRT windowed timing mode have allowed us to extend the GBM spectral coverage for these events down to the X-ray domain (0.5-10 keV). Our earlier analysis of the GBM data found that the SGR J1550-5418 burst spectra were described equally well with either a Comptonized model or with two blackbody functions; the two models were statistically indistinguishable. Our new broadband (0.5-200 keV) spectral fits show that, on average, the burst spectra are better described with two blackbody functions than with the Comptonized model. Thus, our joint XRT-GBM analysis clearly shows for the first time that the SGR J1550-5418 burst spectra might naturally be expected to exhibit a more truly thermalized character, such as a two-blackbody or even a multi-blackbody signal. Using the Swift and RXTE timing ephemeris for SGR J1550-5418 we construct the distribution of the XRT burst counts with spin phase and find that it is not correlated with the persistent X-ray emission pulse phase from SGR J1550-5418. These results indicate that the burst emitting sites on the neutron star need not to be co-located with hot spots emitting the bulk of the persistent X-ray emission. Finally, we show that there is a significant pulse phase dependence of the XRT burst counts, likely demonstrating that the surface magnetic field of SGR J1550-5418 is not uniform over the emission zones, since it is anticipated that regions with stronger surface magnetic field could trigger bursts more efficiently.

  13. A NEW METHOD OF PULSE-WISE SPECTRAL ANALYSIS OF GAMMA-RAY BURSTS

    SciTech Connect (OSTI)

    Basak, Rupal; Rao, A. R., E-mail: rupalb@tifr.res.in, E-mail: arrao@tifr.res.in [Tata Institute of Fundamental Research, Mumbai-400005 (India)

    2013-05-10

    Time-resolved spectral analysis, though a very promising method to understand the emission mechanism of gamma-ray bursts (GRBs), is difficult to implement in practice because of poor statistics. We present a new method for pulse-wise time-resolved spectral study of the individual pulses of GRBs, using the fact that many spectral parameters are either constants or smooth functions of time. We use this method for the two pulses of GRB 081221, the brightest GRB with separable pulses. We choose, from the literature, a set of possible models that includes the Band model, blackbody with a power law (BBPL), and a collection of blackbodies with a smoothly varying temperature profile, along with a power law (mBBPL), and two blackbodies with a power law (2BBPL). First, we perform a time-resolved study to confirm the spectral parameter variations, and then we construct the new model to perform a joint spectral fit. We find that any photospheric emission in terms of blackbodies is required mainly in the rising parts of the pulses and the falling part can be adequately explained in terms of the Band model, with the low-energy photon index within the regime of synchrotron model. Interestingly, we find that 2BBPL is comparable or sometimes even better, though marginally, than the Band model, in all episodes. Consistent results are also obtained for the brightest GRB of Fermi era-GRB 090618. We point out that the method is generic enough to test any spectral model with well-defined parameter variations.

  14. NuSTAR observations of magnetar 1E 1841–045

    SciTech Connect (OSTI)

    An, Hongjun; Kaspi, Victoria M.; Dufour, François; Archibald, Robert [Department of Physics, McGill University, Montreal, Quebec H3A 2T8 (Canada); Hascoët, Romain; Beloborodov, Andrei M.; Gotthelf, Eric V.; Hailey, Charles J. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Bachetti, Matteo [Université de Toulouse, UPS-OMP, IRAP, Toulouse (France); Boggs, Steven E.; Craig, William W. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Christensen, Finn E. [DTU Space, National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Greffenstette, Brian W.; Harrison, Fiona A.; Madsen, Kristin K. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Kitaguchi, Takao [RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Kouveliotou, Chryssa [Space Science Office, ZP12, NASA Marshall Space Flight Center, Huntsville, AL 35812 (United States); Markwardt, Craig B. [Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Stern, Daniel [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Vogel, Julia K. [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); and others

    2013-12-20

    We report new spectral and temporal observations of the magnetar 1E 1841–045 in the Kes 73 supernova remnant obtained with the Nuclear Spectroscopic Telescope Array. Combined with new Swift and archival XMM-Newton and Chandra observations, the phase-averaged spectrum is well characterized by a blackbody plus double power law, in agreement with previous multimission X-ray results. However, we are unable to reproduce the spectral results reported based on Suzaku observations. The pulsed fraction of the source is found to increase with photon energy. The measured rms pulsed fractions are ?12% and ?17% at ?20 and ?50 keV, respectively. We detect a new feature in the 24-35 keV band pulse profile that is uniquely double peaked. This feature may be associated with a possible absorption or emission feature in the phase-resolved spectrum. We fit the X-ray data using the recently developed electron-positron outflow model by Beloborodov for the hard X-ray emission from magnetars. This produces a satisfactory fit, allowing a constraint on the angle between the rotation and magnetic axes of the neutron star of ?20° and on the angle between the rotation axis and line of sight of ?50°. In this model, the soft X-ray component is inconsistent with a single blackbody; adding a second blackbody or a power-law component fits the data. The two-blackbody interpretation suggests a hot spot of temperature kT ? 0.9 keV occupying ?1% of the stellar surface.

  15. Q&A with Nobelist George Smoot - 2009 BCCP Cosmology Workshop

    ScienceCinema (OSTI)

    George Smoot

    2010-09-01

    July 2009: What happens when dark matter and anti-dark mattter collide? If you were in a gravity free environment, what would happen to time? At the annual Cosmology Workshop at Lawrence Berkeley Lab, Nobelist George Smoot answers these questions and more from high school students and teachers. Dr. Smoot was co-awarded the 2006 Nobel Prize in Physics for the discovery of the blackbody form and anisotropy of the cosmic microwave background radiation.

  16. Estimation of radiative properties and temperature distributions in coal-fired boiler furnaces by a portable image processing system

    SciTech Connect (OSTI)

    Li, Wenhao; Lou, Chun; Sun, Yipeng; Zhou, Huaichun

    2011-02-15

    This paper presented an experimental investigation on the estimation of radiative properties and temperature distributions in a 670 t/h coal-fired boiler furnace by a portable imaging processing system. The portable system has been calibrated by a blackbody furnace. Flame temperatures and emissivities were measured by the portable system and equivalent blackbody temperatures were deduced. Comparing the equivalent blackbody temperatures measured by the portable system and the infrared pyrometer, the relative difference is less than 4%. The reconstructed pseudo-instantaneous 2-D temperature distributions in two cross-sections can disclose the combustion status inside the furnace. The measured radiative properties of particles in the furnace proved there is significant scattering in coal-fired boiler furnaces and it can provide useful information for the calculation of radiative heat transfer and numerical simulation of combustion in coal-fired boiler furnaces. The preliminary experimental results show this technology will be helpful for the combustion diagnosis in coal-fired boiler furnaces. (author)

  17. The spectral irradiance traceability chain at PTB

    SciTech Connect (OSTI)

    Sperfeld, P.; Pape, S.; Nevas, S.

    2013-05-10

    Spectral irradiance is a fundamental radiometric unit. Its application to measurement results requires qualified traceability to basic units of the international system of units (Systeme international d'unites, SI). The Physikalisch-Technische Bundesanstalt (PTB) is amongst other national metrological institutes (NMIs) responsible for the realization, maintenance and dissemination of various radiometric and photometric units based on and traceable to national standards. The unit of spectral irradiance is realized and represented by a blackbody-radiator as the national primary standard of the PTB. Based on Planck's radiation law, the irradiance is calculated and realized for any wavelength taking into account the exact knowledge of the radiation temperature and the geometrical parameters. Using a double-monochromator-based spectroradiometer system, secondary standard lamps can be calibrated by direct comparison to the blackbody-radiator (substitution method). These secondary standard lamps are then used at the PTB to calibrate standard lamps of customers. The customers themselves use these so-called transfer standards to calibrate their working standard lamps. These working standards are then used to calibrate own spectroradiometers or sources. This rather complex calibration chain is a common procedural method that for the customers generally leads to satisfying measurement results on site. Nevertheless, the standard lamps in use have to fulfill highest requirements concerning stability and reproducibility. Only this allows achieving comparably low transfer measurement uncertainties, which occur at each calibration step. Thus, the PTB is constantly investigating the improvement and further development of transfer standards and measurement methods for various spectral regions. The realization and dissemination of the spectral irradiance using the blackbody-radiator at the PTB is accomplished with worldwide approved minimized measurement uncertainties confirmed by international intercomparisons among NMIs. Ultimately, the spectral irradiance can be realized with expanded measurement uncertainties of far less than 1 % over a wide spectral range. Thus, for customers with high demands on low measurement uncertainties, it is possible to calibrate their working standards directly against the blackbody-radiator, taking into account the higher necessary effort. In special cases it is possible to calibrate the customer's spectroradiometric facilities directly in front of the blackbody-radiator. In the context of the European Metrology Research Project Traceability for surface spectral solar ultraviolet radiation, the traceability chain will be improved and adapted.

  18. Ice Concentration Retrieval in Stratiform Mixed-phase Clouds Using Cloud Radar Reflectivity Measurements and 1D Ice Growth Model Simulations

    SciTech Connect (OSTI)

    Zhang, Damao; Wang, Zhien; Heymsfield, Andrew J.; Fan, Jiwen; Luo, Tao

    2014-10-01

    Measurement of ice number concentration in clouds is important but still challenging. Stratiform mixed-phase clouds (SMCs) provide a simple scenario for retrieving ice number concentration from remote sensing measurements. The simple ice generation and growth pattern in SMCs offers opportunities to use cloud radar reflectivity (Ze) measurements and other cloud properties to infer ice number concentration quantitatively. To understand the strong temperature dependency of ice habit and growth rate quantitatively, we develop a 1-D ice growth model to calculate the ice diffusional growth along its falling trajectory in SMCs. The radar reflectivity and fall velocity profiles of ice crystals calculated from the 1-D ice growth model are evaluated with the Atmospheric Radiation Measurements (ARM) Climate Research Facility (ACRF) ground-based high vertical resolution radar measurements. Combining Ze measurements and 1-D ice growth model simulations, we develop a method to retrieve the ice number concentrations in SMCs at given cloud top temperature (CTT) and liquid water path (LWP). The retrieved ice concentrations in SMCs are evaluated with in situ measurements and with a three-dimensional cloud-resolving model simulation with a bin microphysical scheme. These comparisons show that the retrieved ice number concentrations are within an uncertainty of a factor of 2, statistically.

  19. Fourier resolved spectroscopy of 4U 1728-34: New Insights into Spectral and Temporal Properties of Low-Mass X-ray Binaries

    E-Print Network [OSTI]

    C. R. Shrader; P. Reig; D. Kazanas

    2007-06-11

    Using archival RXTE data we derive the 2-16 keV Fourier-resolved spectra of the Atoll source 4U 1728-34 in a sequence of its timing states as its low QPO frequency spans the range between 6 and 94 Hz. The increase in the QPO frequency accompanies a spectral transition of the source from its island to its banana states. The banana-states' Fourier-resolved spectra are well fitted by a single blackbody component with $kT \\sim 2-3$ keV depending on the source position in the color -- color diagram and the Fourier frequency, thus indicating that this spectral component is responsible for the source variability on these timescales. This result is in approximate agreement with similar behavior exhibited by the Z sources, suggesting that, as in that case, the boundary layer -- the likely source of the thermal component -- is supported by radiation pressure. Furthermore, it is found that the iron line at $\\sim$6.6 keV, clearly present in the averaged spectra, not apparent within the limitations of our measurements in the frequency-resolved spectra irrespective of the frequency range. This would indicate that this spectral component exhibits little variability on time scales comprising the interval $10^{-2}-10^2$ seconds. In the island state the single blackbody model proved inadequate, particularly notable in our lowest frequency band ($0.008-0.8$ Hz). An absorbed powerlaw or an additive blackbody plus hard powerlaw model was required to obtain a satisfactory fit. Statistics do not allow unambiguous discrimination between these possible scenarios.

  20. DUST AND GAS IN THE MAGELLANIC CLOUDS FROM THE HERITAGE HERSCHEL KEY PROJECT. I. DUST PROPERTIES AND INSIGHTS INTO THE ORIGIN OF THE SUBMILLIMETER EXCESS EMISSION

    SciTech Connect (OSTI)

    Gordon, Karl D.; Roman-Duval, Julia; Meixner, Margaret; Bot, Caroline; Babler, Brian; Bernard, Jean-Philippe; Bolatto, Alberto; Jameson, Katherine; Boyer, Martha L.; Clayton, Geoffrey C.; Engelbracht, Charles; Fukui, Yasuo; Galametz, Maud; Galliano, Frederic; Hony, Sacha; Lebouteiller, Vianney; Indebetouw, Remy; Israel, Frank P.; Kawamura, Akiko; and others

    2014-12-20

    The dust properties in the Large and Small Magellanic clouds (LMC/SMC) are studied using the HERITAGE Herschel Key Project photometric data in five bands from 100 to 500 ?m. Three simple models of dust emission were fit to the observations: a single temperature blackbody modified by a power-law emissivity (SMBB), a single temperature blackbody modified by a broken power-law emissivity (BEMBB), and two blackbodies with different temperatures, both modified by the same power-law emissivity (TTMBB). Using these models, we investigate the origin of the submillimeter excess, defined as the submillimeter emission above that expected from SMBB models fit to observations <200 ?m. We find that the BEMBB model produces the lowest fit residuals with pixel-averaged 500 ?m submillimeter excesses of 27% and 43% for the LMC and SMC, respectively. Adopting gas masses from previous works, the gas-to-dust ratios calculated from our fitting results show that the TTMBB fits require significantly more dust than are available even if all the metals present in the interstellar medium (ISM) were condensed into dust. This indicates that the submillimeter excess is more likely to be due to emissivity variations than a second population of colder dust. We derive integrated dust masses of (7.3 ± 1.7) × 10{sup 5} and (8.3 ± 2.1) × 10{sup 4} M {sub ?} for the LMC and SMC, respectively. We find significant correlations between the submillimeter excess and other dust properties; further work is needed to determine the relative contributions of fitting noise and ISM physics to the correlations.

  1. Laser induced rovibrational cooling of the linear polyatomic ion C{sub 2}H{sub 2}{sup +}

    SciTech Connect (OSTI)

    Deb, Nabanita; Heazlewood, Brianna R.; Rennick, Christopher J.; Softley, Timothy P.

    2014-04-28

    The laser-induced blackbody-assisted rotational cooling of a linear polyatomic ion, C{sub 2}H{sub 2}{sup +}, in its {sup 2}? ground electronic state in the presence of the blackbody radiation field at 300 K and 77 K is investigated theoretically using a rate-equations model. Although pure rotational transitions are forbidden in this non-polar species, the ?{sub 5} cis-bending mode is infrared active and the (1-0) band of this mode strongly overlaps the 300 K blackbody spectrum. Hence the lifetimes of state-selected rotational levels are found to be short compared to the typical timescale of ion trapping experiments. The ?{sub 5} (1-0) transition is split by the Renner-Teller coupling of vibrational and electronic angular momentum, and by the spin-orbit coupling, into six principal components and these effects are included in the calculations. In this paper, a rotational-cooling scheme is proposed that involves simultaneous pumping of a set of closely spaced Q-branch transitions on the {sup 2}?{sub 5/2} ? {sup 2}?{sub 3/2} band together with two Q-branch lines in the {sup 2}?{sup +} ? {sup 2}?{sub 1/2} band. It is shown that this should lead to >70% of total population in the lowest rotational level at 300 K and over 99% at 77 K. In principle, the multiple Q-branch lines could be pumped with just two broad-band (??? = 0.4–3 cm{sup ?1}) infrared lasers.

  2. A broadband X-ray study of the Geminga pulsar with NuSTAR And XMM-Newton

    SciTech Connect (OSTI)

    Mori, Kaya; Gotthelf, Eric V.; Halpern, Jules P.; Beloborodov, Andrei M.; Hailey, Charles J. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Dufour, Francois; Kaspi, Victoria M.; An, Hongjun [Department of Physics, McGill University, Montreal, QC H3A2T8 (Canada); Bachetti, Matteo [Université de Toulouse, UPS-OMP, IRAP, Toulouse (France); Boggs, Steven E.; Craig, William W. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Christensen, Finn E. [DTU Space—National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Harrison, Fiona A. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Kouveliotou, Chryssa [NASA Marshall Space Flight Center, Huntsville, AL 35812 (United States); Pivovaroff, Michael J. [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Stern, Daniel [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Zhang, William W., E-mail: kaya@astro.columbia.edu [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2014-10-01

    We report on the first hard X-ray detection of the Geminga pulsar above 10 keV using a 150 ks observation with the Nuclear Spectroscopic Telescope Array (NuSTAR) observatory. The double-peaked pulse profile of non-thermal emission seen in the soft X-ray band persists at higher energies. Broadband phase-integrated spectra over the 0.2-20 keV band with NuSTAR and archival XMM-Newton data do not fit to a conventional two-component model of a blackbody plus power law, but instead exhibit spectral hardening above ?5 keV. We find that two spectral models fit the data well: (1) a blackbody (kT {sub 1} ? 42 eV) with a broken power law (?{sub 1} ? 2.0, ?{sub 2} ? 1.4 and E {sub break} ? 3.4 keV) and (2) two blackbody components (kT {sub 1} ? 44 eV and kT {sub 2} ? 195 eV) with a power-law component (? ? 1.7). In both cases, the extrapolation of the Rayleigh-Jeans tail of the thermal component is consistent with the UV data, while the non-thermal component overpredicts the near-infrared data, requiring a spectral flattening at E ? 0.05-0.5 keV. While strong phase variation of the power-law index is present below ?5 keV, our phase-resolved spectroscopy with NuSTAR indicates that another hard non-thermal component with ? ? 1.3 emerges above ?5 keV. The spectral hardening in non-thermal X-ray emission as well as spectral flattening between the optical and X-ray bands argue against the conjecture that a single power law may account for multi-wavelength non-thermal spectra of middle-aged pulsars.

  3. Thermally-activated non-local amplification in quantum energy transport

    E-Print Network [OSTI]

    Bruno Leggio; Riccardo Messina; Mauro Antezza

    2015-11-18

    We study energy-transport efficiency in light-harvesting planar and 3D complexes of two-level atomic quantum systems, embedded in a common thermal blackbody radiation. We show that the collective non-local dissipation induced by the thermal bath plays a fundamental role in energy transport. It gives rise to a dramatic enhancement of the energy-transport efficiency, which may largely overcome $100\\%$. This effect, which improves the understanding of transport phenomena in experimentally relevant complexes, suggests a particularly promising mechanism for quantum energy management.

  4. Limits on iron-dominated fallback disk in SN 1987A

    E-Print Network [OSTI]

    K. Werner; T. Nagel; T. Rauch

    2007-03-20

    The non-detection of a point source in SN1987A imposes an upper limit for the optical luminosity of L=2L_sun. This limits the size of a possible fallback disk around the stellar remnant. Assuming a steady-state thin disk with blackbody emission requires a disk smaller than 100,000 km if the accretion rate is at 30% of the Eddington rate (Graves et al. 2005). We have performed detailed non-LTE radiation transfer calculations to model the disk spectrum more realistically. It turns out that the observational limit on the disk extension becomes even tighter, namely 70,000 km.

  5. Planck's Radiation Law in the Quantized Universe

    E-Print Network [OSTI]

    Rainer Collier

    2014-09-15

    Physical research looks for clues to quantum properties of the gravitational field. On the basis of the common Schr\\"odinger theory, a simple model of the quantization of a Friedmann universe comprising dust and radiation is investigated. With regard to energy quantization, the result suggests a universal limitation of the energy spacing between neighbouring quantum states by the Planck energy. Applied to black-body radiation, a modified Planck radiation law follows. If this could be verified in the laboratory, it would provide a direct hint at quantum properties of the space-time manifold.

  6. Laser-induced light emission from carbon nanoparticles

    SciTech Connect (OSTI)

    Osswald, S.; Behler, K.; Gogotsi, Y.

    2008-10-01

    Strong absorption of light in a broad wavelength range and poor thermal conductance between particles of carbon nanomaterials, such as nanotubes, onions, nanodiamond, and carbon black, lead to strong thermal emission (blackbody radiation) upon laser excitation, even at a very low (milliwatts) power. The lasers commonly used during Raman spectroscopy characterization of carbon can cause sample heating to very high temperatures. While conventional thermometry is difficult in the case of nanomaterials, Raman spectral features, such as the G band of graphitic carbon and thermal emission spectra were used to estimate the temperature during light emission that led to extensive graphitization and evaporation of carbon nanomaterials, indicating local temperatures exceeding 3500 deg. C.

  7. Optimized Phosphors for Warm White LED Light Engines

    SciTech Connect (OSTI)

    Setlur, Anant; Brewster, Megan; Garcia, Florencio; Hill, M. Christine; Lyons, Robert; Murphy, James; Stecher, Tom; Stoklosa, Stan; Weaver, Stan; Happek, Uwe; Aesram, Danny; Deshpande, Anirudha

    2012-07-30

    The objective of this program is to develop phosphor systems and LED light engines that have steady-state LED efficacies (using LEDs with a 60% wall-plug efficiency) of 105–120 lm/W with correlated color temperatures (CCT) ~3000 K, color rendering indices (CRI) >85, <0.003 distance from the blackbody curve (dbb), and <2% loss in phosphor efficiency under high temperature, high humidity conditions. In order to reach these goals, this involves the composition and processing optimization of phosphors previously developed by GE in combination with light engine package modification.

  8. Fine Structure of Dark Energy and New Physics

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Jejjala, Vishnu; Kavic, Michael; Minic, Djordje

    2007-01-01

    Following our recent work on the cosmological constant problem, in this letter we make a specific proposal regarding the fine structure (i.e., the spectrum) of dark energy. The proposal is motivated by a deep analogy between the blackbody radiation problem, which led to the development of quantum theory, and the cosmological constant problem, for which we have recently argued calls for a conceptual extension of the quantum theory. We argue that the fine structure of dark energy is governed by a Wien distribution, indicating its dual quantum and classical nature. We discuss observational consequences of such a picture of darkmore »energy and constrain the distribution function.« less

  9. Thermal radiation, radiation force and dynamics of a polarizable particle

    E-Print Network [OSTI]

    G. V. Dedkov; A. A. Kyasov

    2015-08-26

    We discuss basic expressions and interrelations between various physical quantities describing the fluctuation-electromagnetic interaction of a small polarizable particle during relativistic motion relative to the blackbody radiation, namely tangential radiation force, rate of heating, intensity of thermal radiation/absorption, the change of the rest mass of a particle, and acceleration. We obtain an explicit formula for the frictional force acting on the particle in its rest frame and discuss its connection with the particle acceleration and the tangential force given in the reference frame of background radiation. The criticism of our previous results in recent paper by A. I. Volokitin (Phys. Rev. A81, 2015, 032505) is refuted.

  10. Measurement of the Energy Relaxation Time in rf SQUID Flux Qubits

    E-Print Network [OSTI]

    Qiu, Wei

    2007-12-17

    in the resistors could drive the superconducting wires normal all the way down to the sample cell. To attenuate blackbody radiation from wires at higher temperatures a 12- channel microwave copper powder filter (CPF) [66] has been constructed for the experiment.... The CPF consists of 12 NbTi wire spiral coils inside a copper box filled with 325 mesh Cu powder with grain size of 3.254.5 ?m: . The CPF is equipped with two Cinch connectors, as displayed in Figure 2.6, and was thermally anchored at the mixing...

  11. Thermally-activated non-local amplification in quantum energy transport

    E-Print Network [OSTI]

    Bruno Leggio; Riccardo Messina; Mauro Antezza

    2015-05-13

    We study energy-transport efficiency in light-harvesting planar and 3D complexes of two-level atomic quantum systems, embedded in a common thermal blackbody radiation. We show that the collective non-local dissipation induced by the thermal bath plays a fundamental role in energy transport. It gives rise to a dramatic enhancement of the energy-transport efficiency, which may largely overcome $100\\%$. This effect, which improves the understanding of transport phenomena in experimentally relevant complexes, suggests a particularly promising mechanism for quantum energy management.

  12. High-Performance Nanostructured Coating

    Office of Energy Efficiency and Renewable Energy (EERE)

    The High-Performance Nanostructured Coating fact sheet details a SunShot project led by a University of California, San Diego research team working to develop a new high-temperature spectrally selective coating for receiver surfaces. These receiver surfaces, used in concentrating solar power systems, rely on high-temperature SSCs to effectively absorb solar energy without emitting much blackbody radiation.The optical properties of the SSC directly determine the efficiency and maximum attainable temperature of solar receivers, which in turn influence the power-conversion efficiency and overall system cost.

  13. Fully QED/relativistic theory of light pressure on free electrons by isotropic radiation

    E-Print Network [OSTI]

    A. E. Kaplan

    2015-07-27

    A relativistic/QED theory of light pressure on electrons by an isotropic, in particular blackbody radiation predicts thermalization rates of free electrons over entire span of energies available in the lab and the nature. The calculations based on the QED Klein-Nishina theory of electron-photon scattering and relativistic Fokker-Planck equation, show that the transition from classical (Thompson) to QED (Compton) thermalization determined by the product of electron energy and radiation temperature, is reachable under conditions for controlled nuclear fusion, and predicts large acceleration of electron thermalization in the Compton domain and strong damping of plasma oscillations at the temperatures near plasma nuclear fusion.

  14. Slide 1

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effect Photovoltaics -7541 * Velocity and turbulencetheSUMMARYin the Blackbody

  15. Atmospheric Radiation Measurement program climate research facilities quarterly report April 1 - June 30, 2009.

    SciTech Connect (OSTI)

    Sisterson, D. L.

    2009-07-14

    Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near-real time. Raw and processed data are then sent approximately daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998. The U.S. Department of Energy (DOE) requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1 - (ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for the third quarter of FY 2009 for the Southern Great Plains (SGP) site is 2,074.80 hours (0.95 x 2,184 hours this quarter); for the North Slope Alaska (NSA) locale it is 1,965.60 hours (0.90 x 2,184); and for the Tropical Western Pacific (TWP) locale it is 1,856.40 hours (0.85 x 2,184). The ARM Mobile Facility (AMF) was officially operational May 1 in Graciosa Island, the Azores, Portugal, so the OPSMAX time this quarter is 1390.80 hours (0.95 x 1464). The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or data stream. Data availability reported here refers to the average of the individual, continuous data streams that have been received by the Archive. Data not at the Archive are caused by downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is directly related to individual instrument uptime. Thus, the average percentage of data in the Archive represents the average percentage of the time (24 hours per day, 91 days for this quarter) the instruments were operating this quarter. Table 1 shows the accumulated maximum operation time (planned uptime), actual hours of operation, and variance (unplanned downtime) for April 1 - June 30, 2009, for the fixed sites. Because the AMF operates episodically, the AMF statistics are reported separately and are not included in the aggregate average with the fixed sites. The AMF statistics for this reporting period were not available at the time of this report. The third quarter comprises a total of 2,184 hours for the fixed sites. The average well exceeded our goal this quarter.

  16. Atmospheric Radiation Measurement program climate research facility operations quarterly report July 1 - Sep. 30, 2009.

    SciTech Connect (OSTI)

    Sisterson, D. L.

    2009-10-15

    Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near-real time. Raw and processed data are then sent approximately daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998. The U.S. Department of Energy (DOE) requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1 - (ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for the fourth quarter of FY 2009 for the Southern Great Plains (SGP) site is 2,097.60 hours (0.95 ? 2,208 hours this quarter). The OPSMAX for the North Slope Alaska (NSA) locale is 1,987.20 hours (0.90 ? 2,208) and for the Tropical Western Pacific (TWP) locale is 1,876.8 hours (0.85 ? 2,208). The ARM Mobile Facility (AMF) was officially operational May 1 in Graciosa Island, the Azores, Portugal, so the OPSMAX time this quarter is 2,097.60 hours (0.95 x 2,208). The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or data stream. Data availability reported here refers to the average of the individual, continuous data streams that have been received by the Archive. Data not at the Archive result from downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is directly related to individual instrument uptime. Thus, the average percentage of data in the Archive represents the average percentage of the time (24 hours per day, 92 days for this quarter) the instruments were operating this quarter. Table 1 shows the accumulated maximum operation time (planned uptime), actual hours of operation, and variance (unplanned downtime) for the period July 1 - September 30, 2009, for the fixed sites. Because the AMF operates episodically, the AMF statistics are reported separately and not included in the aggregate average with the fixed sites. The fourth quarter comprises a total of 2,208 hours for the fixed and mobile sites. The average of the fixed sites well exceeded our goal this quarter. The AMF data statistic requires explanation. Since the AMF radar data ingest software is being modified, the data are being stored in the DMF for data processing. Hence, the data are not at the Archive; they are anticipated to become available by the next report.

  17. Atmospheric Radiation Measurement program climate research facility operations quarterly report January 1 - March 31, 2009.

    SciTech Connect (OSTI)

    Sisterson, D. L.

    2009-04-23

    Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998. The U.S. Department of Energy (DOE) requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1 - (ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for the second quarter of FY 2009 for the Southern Great Plains (SGP) site is 2,052.00 hours (0.95 x 2,160 hours this quarter). The OPSMAX for the North Slope Alaska (NSA) locale is 1,944.00 hours (0.90 x 2,160), and for the Tropical Western Pacific (TWP) locale is 1,836.00 hours (0.85 x 2,160). The OPSMAX time for the ARM Mobile Facility (AMF) is not reported this quarter because not all of the metadata have been acquired that are used to generate this metric. The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or data stream. Data availability reported here refers to the average of the individual, continuous data streams that have been received by the Archive. Data not at the Archive are caused by downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is directly related to individual instrument uptime. Thus, the average percentage of data in the Archive represents the average percentage of the time (24 hours per day, 90 days for this quarter) the instruments were operating this quarter. Summary. Table 1 shows the accumulated maximum operation time (planned uptime), actual hours of operation, and variance (unplanned downtime) for the period January 1 - March 31, 2009, for the fixed sites. The AMF has completed its mission in China but not all of the data can be released to the public at the time of this report. The second quarter comprises a total of 2,160 hours. The average exceeded our goal this quarter.

  18. Atmospheric Radiation Measurement program climate research facility operations quarterly report.

    SciTech Connect (OSTI)

    Sisterson, D. L.; Decision and Information Sciences

    2006-09-06

    Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year dating back to 1998. The U.S. Department of Energy requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1-(ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for the third quarter for the Southern Great Plains (SGP) site is 2,074.80 hours (0.95 x 2,184 hours this quarter). The OPSMAX for the North Slope Alaska (NSA) locale is 1,965.60 hours (0.90 x 2,184), and that for the Tropical Western Pacific (TWP) locale is 1,856.40 hours (0.85 x 2,184). The OPSMAX time for the ARM Mobile Facility (AMF) is 2,074.80 hours (0.95 x 2,184). The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or data stream. Data availability reported here refers to the average of the individual, continuous data streams that have been received by the Archive. Data not at the Archive are caused by downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is directly related to individual instrument uptime. Thus, the average percent of data in the Archive represents the average percent of the time (24 hours per day, 91 days for this quarter) the instruments were operating this quarter. Table 1 shows the accumulated maximum operation time (planned uptime), the actual hours of operation, and the variance (unplanned downtime) for the period April 1 through June 30, 2006, for the fixed and mobile sites. Although the AMF is currently up and running in Niamey, Niger, Africa, the AMF statistics are reported separately and not included in the aggregate average with the fixed sites. The third quarter comprises a total of 2,184 hours. For all fixed sites (especially the TWP locale) and the AMF, the actual data availability (and therefore actual hours of operation) exceeded the individual (and well as aggregate average of the fixed sites) operational goal for the third quarter of fiscal year (FY) 2006.

  19. Atmospheric Radiation Measurement program climate research facility operations quarterly report April 1 - June 30, 2007.

    SciTech Connect (OSTI)

    Sisterson, D. L.

    2007-07-26

    Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998. The U.S. Department of Energy requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1 - (ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for the third quarter of FY 2007 for the Southern Great Plains (SGP) site is 2,074.8 hours (0.95 x 2,184 hours this quarter). The OPSMAX for the North Slope Alaska (NSA) locale is 1,965.6 hours (0.90 x 2,184), and that for the Tropical Western Pacific (TWP) locale is 1,856.4 hours (0.85 x 2,184). The OPSMAX time for the ARM Mobile Facility (AMF) is 2,074.8 hours (0.95 x 2,184). The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or data stream. Data availability reported here refers to the average of the individual, continuous data streams that have been received by the Archive. Data not at the Archive are caused by downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is directly related to individual instrument uptime. Thus, the average percent of data in the Archive represents the average percent of the time (24 hours per day, 91 days for this quarter) the instruments were operating this quarter. Table 1 shows the accumulated maximum operation time (planned uptime), the actual hours of operation, and the variance (unplanned downtime) for the period April 1 through June 30, 2007, for the fixed sites only. The AMF has been deployed to Germany and is operational this quarter. The third quarter comprises a total of 2,184 hours. Although the average exceeded our goal this quarter, there were cash flow issues resulting from Continuing Resolution early in the period that did not allow for timely instrument repairs that kept our statistics lower than past quarters at all sites. The low NSA numbers resulted from missing MFRSR data this spring that appears to be recoverable but not available at the Archive at the time of this report.

  20. Spectral Formation in X-Ray Pulsars: Bulk Comptonization in the Accretion Shock

    E-Print Network [OSTI]

    Peter A. Becker; Michael T. Wolff

    2005-05-06

    Accretion-powered X-ray pulsars are among the most luminous X-ray sources in the Galaxy. However, despite decades of theoretical and observational work since their discovery, no satisfactory model for the formation of the observed X-ray spectra has emerged. In particular, the previously available theories are unable to reproduce the power-law variation observed at high energies in many sources. In this paper, we present the first self-consistent calculation of the spectrum emerging from a pulsar accretion column that includes an explicit treatment of the energization occurring in the shock. Using a rigorous eigenfunction expansion method based on the exact dynamical solution for the velocity profile in the column, we obtain a closed-form expression for the Green's function describing the upscattering of radiation injected into the column from a monochromatic source located at the top of the thermal mound, near the base of the flow. The Green's function is convolved with a Planck distribution to calculate the radiation spectrum resulting from the reprocessing of blackbody photons emitted by the thermal mound. We demonstrate that the energization of the photons in the shock naturally produces an X-ray spectrum with a power-law shape at high energies and a blackbody shape at low energies, in agreement with many observations of accreting X-ray pulsars.

  1. Spectral Formation in X-Ray Pulsar Accretion Columns

    E-Print Network [OSTI]

    Peter A. Becker; Michael T. Wolff

    2005-03-03

    We present the first self-consistent model for the dynamics and the radiative transfer occurring in bright X-ray pulsar accretion columns, with a special focus on the role of the shock in energizing the emerging X-rays. The pressure inside the accretion column of a luminous X-ray pulsar is dominated by the photons, and consequently the equations describing the coupled radiative-dynamical structure must be solved simultaneously. Spectral formation in these sources is therefore a complex, nonlinear phenomenon. We obtain the analytical solution for the Green's function describing the upscattering of monochromatic radiation injected into the column from the thermal mound located near the base of the flow. The Green's function is convolved with a Planck distribution to model the X-ray spectrum resulting from the reprocessing of blackbody photons produced in the thermal mound. These photons diffuse through the infalling gas and eventually escape out the walls of the column, forming the observed X-ray spectrum. We show that the resulting column-integrated, phase-averaged spectrum has a power-law shape at high energies and a blackbody shape at low energies, in agreement with the observational data for many X-ray pulsars.

  2. Thermality of the Hawking flux

    E-Print Network [OSTI]

    Matt Visser

    2015-05-06

    Is the Hawking flux "thermal"? Unfortunately, the answer to this seemingly innocent question depends on a number of often unstated, but quite crucial, technical assumptions built into modern (mis-)interpretations of the word "thermal". The original 1850's notions of thermality --- based on classical thermodynamic reasoning applied to idealized "black bodies" or "lamp black surfaces" --- when supplemented by specific basic quantum ideas from the early 1900's, immediately led to the notion of the black-body spectrum, (the Planck-shaped spectrum), but "without" any specific assumptions or conclusions regarding correlations between the quanta. Many (not all) modern authors (often implicitly and unintentionally) add an extra, and quite unnecessary, assumption that there are no correlations in the black-body radiation; but such usage is profoundly ahistorical and dangerously misleading. Specifically, the Hawking flux from an evaporating black hole, (just like the radiation flux from a leaky furnace or a burning lump of coal), is only "approximately" Planck-shaped over a bounded frequency range. Standard physics (phase space and adiabaticity effects) explicitly bound the frequency range over which the Hawking flux is "approximately" Planck-shaped from both above and below --- the Hawking flux is certainly not exactly Planckian, and there is no compelling physics reason to assume the Hawking photons are uncorrelated.

  3. Pigmented foils for radiative cooling and condensation irrigation

    SciTech Connect (OSTI)

    Nilsson, T.M.J.; Vargas, W.E.; Niklasson, G.A.

    1994-12-31

    This paper reports on the development of pigmented polyethylene foils for radiative cooling. The optical properties of the foils were optimized for applications in day-time radiative cooling and water condensation. The authors first study highly scattering foils used as convection shields. These cover foils combine a high solar reflectance and a high transmittance in the atmospheric window region in the infrared. Different pigment materials were studied and ZnS was the only one that could prevent heating of an underlying blackbody at noon, with the sun in its zenith. A 400 {micro}m thick ZnS pigmented polyethylene foil with a pigment volume fraction of 0.15 was tested in Tanzania. At noon the observed temperature of the covered blackbody was only 1.5 K above the ambient. Secondly, they study the potential for condensation of water in an arid region. Pigmented foils for this purpose should combine a high solar reflectance and a high infrared emittance, in order to promote condensation by the radiative cooling effect. Titanium dioxide is a fairly good infrared emitter, but the emittance can be improved by using a mixture of TiO{sub 2} and BaSO{sub 4} pigments or only employing a composite SiO{sub 2}/TiO{sub 2}. Field tests with a 390 {micro}m thick polyethylene foil with TiO{sub 2} and BaSO{sub 4} pigments gave encouraging results.

  4. Single-fiber multi-color pyrometry

    DOE Patents [OSTI]

    Small, IV, Ward; Celliers, Peter

    2004-01-27

    This invention is a fiber-based multi-color pyrometry set-up for real-time non-contact temperature and emissivity measurement. The system includes a single optical fiber to collect radiation emitted by a target, a reflective rotating chopper to split the collected radiation into two or more paths while modulating the radiation for lock-in amplification (i.e., phase-sensitive detection), at least two detectors possibly of different spectral bandwidths with or without filters to limit the wavelength regions detected and optics to direct and focus the radiation onto the sensitive areas of the detectors. A computer algorithm is used to calculate the true temperature and emissivity of a target based on blackbody calibrations. The system components are enclosed in a light-tight housing, with provision for the fiber to extend outside to collect the radiation. Radiation emitted by the target is transmitted through the fiber to the reflective chopper, which either allows the radiation to pass straight through or reflects the radiation into one or more separate paths. Each path includes a detector with or without filters and corresponding optics to direct and focus the radiation onto the active area of the detector. The signals are recovered using lock-in amplification. Calibration formulas for the signals obtained using a blackbody of known temperature are used to compute the true temperature and emissivity of the target. The temperature range of the pyrometer system is determined by the spectral characteristics of the optical components.

  5. Single-fiber multi-color pyrometry

    DOE Patents [OSTI]

    Small, IV, Ward (Livermore, CA); Celliers, Peter (Berkeley, CA)

    2000-01-01

    This invention is a fiber-based multi-color pyrometry set-up for real-time non-contact temperature and emissivity measurement. The system includes a single optical fiber to collect radiation emitted by a target, a reflective rotating chopper to split the collected radiation into two or more paths while modulating the radiation for lock-in amplification (i.e., phase-sensitive detection), at least two detectors possibly of different spectral bandwidths with or without filters to limit the wavelength regions detected and optics to direct and focus the radiation onto the sensitive areas of the detectors. A computer algorithm is used to calculate the true temperature and emissivity of a target based on blackbody calibrations. The system components are enclosed in a light-tight housing, with provision for the fiber to extend outside to collect the radiation. Radiation emitted by the target is transmitted through the fiber to the reflective chopper, which either allows the radiation to pass straight through or reflects the radiation into one or more separate paths. Each path includes a detector with or without filters and corresponding optics to direct and focus the radiation onto the active area of the detector. The signals are recovered using lock-in amplification. Calibration formulas for the signals obtained using a blackbody of known temperature are used to compute the true temperature and emissivity of the target. The temperature range of the pyrometer system is determined by the spectral characteristics of the optical components.

  6. Modulation and amplification of radiative far field heat transfer : towards a simple radiative thermal transistor

    E-Print Network [OSTI]

    Joulain, Karl; Drevillon, Jeremie; Ben-Abdallah, Philippe

    2015-01-01

    We show in this article that phase change materials (PCM) exhibiting a phase transition between a dielectric state and a metallic state are good candidates to perform modulation as well as amplification of radiative thermal flux. We propose a simple situation in plane parallel geometry where a so-called radiative thermal transistor could be achieved. In this configuration, we put a PCM between two blackbodies at different temperatures. We show that the transistor effect can be achieved easily when this material has its critical temperature between the two blackbody temperatures. We also see, that the more the material is reflective in the metallic state, the more switching effect is realized whereas the more PCM transition is stiff in temperature, the more thermal amplification is high. We finally take the example of VO2 that exhibits an insulator-metallic transition at 68{\\textdegree}C. We show that a demonstrator of a radiative transistor could easily be achieved in view of the heat flux levels predicted. F...

  7. Spectral and Temporal Behavior of the Black Hole Candidate XTE J1118+480 as Observed with BeppoSAX

    E-Print Network [OSTI]

    Frontera, F; Zdziarski, A A; Belloni, T; Del Sordo, S; Masetti, N; Orlandini, M; Palazzi, E

    2003-01-01

    XTE J1118+480 is a well established black hole candidate with a mass estimate in the range from 7 to 10 solar masses. With BeppoSAX we observed the source 4 times, from April to December 2000. Results of the firs t observation were already reported (Frontera et al. 2001). Here we report spectral results of the later observations, performed in May, June and December 2000 and compare them with the results obtained from the 2000 April observation. We observe a decrease of the column density from a value consistent with the Galactic N_H obtained from radio measurement s to a value a factor 2 lower. The spectra are well fit with a thermal Comptonization plus a blackbody model. The blackbody luminosity decreases with time, while the electron temperature of the Comptonizing electron s does not show significant changes. A Compton reflection component is apparent and stable, although weak (mean value of Omega/2pi = 0.21[-0.04,+0.05]). The reflector shows a low metallicity (mean value of Z/Zsun = 0.13[-0.04,+0.06]). On...

  8. Spectral and Temporal Behavior of the Black Hole Candidate XTE J1118+480 as Observed with BeppoSAX

    E-Print Network [OSTI]

    F. Frontera; L. Amati; A. A. Zdziarski; T. Belloni; S. Del Sordo; N. Masetti; M. Orlandini; E. Palazzi

    2003-04-14

    XTE J1118+480 is a well established black hole candidate with a mass estimate in the range from 7 to 10 solar masses. With BeppoSAX we observed the source 4 times, from April to December 2000. Results of the firs t observation were already reported (Frontera et al. 2001). Here we report spectral results of the later observations, performed in May, June and December 2000 and compare them with the results obtained from the 2000 April observation. We observe a decrease of the column density from a value consistent with the Galactic N_H obtained from radio measurement s to a value a factor 2 lower. The spectra are well fit with a thermal Comptonization plus a blackbody model. The blackbody luminosity decreases with time, while the electron temperature of the Comptonizing electron s does not show significant changes. A Compton reflection component is apparent and stable, although weak (mean value of Omega/2pi = 0.21[-0.04,+0.05]). The reflector shows a low metallicity (mean value of Z/Zsun = 0.13[-0.04,+0.06]). On the basis of the spectral results, a hot central disk appears the best scenar io for the high energy photons, while the temporal properties point to a non therma l origin of a fraction of the soft X-ray photons, likely synchrotron emission internal to the hot disk.

  9. Characterization of near-terahertz complementary metal-oxide semiconductor circuits using a Fourier-transform interferometer

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Arenas, D. J.; Shim, Dongha; Koukis, D. I.; Seok, Eunyoung; Tanner, D. B.; O, Kenneth K.

    2011-10-24

    Optical methods for measuring of the emission spectra of oscillator circuits operating in the 400-600 GHz range are described. The emitted power from patch antennas included in the circuits is measured by placing the circuit in the source chamber of a Fourier-transform interferometric spectrometer. The results show that this optical technique is useful for measuring circuits pushing the frontier in operating frequency. The technique also allows the characterization of the circuit by measuring the power radiated in the fundamental and in the harmonics. This capability is useful for oscillator architectures designed to cancel the fundamental and use higher harmonics. Themore »radiated power was measured using two techniques: direct measurement of the power by placing the device in front of a bolometer of known responsivity, and by comparison to the estimated power from blackbody sources. The latter technique showed that these circuits have higher emission than blackbody sources at the operating frequencies, and, therefore, offer potential spectroscopy applications.« less

  10. Optical emission line monitor with background observation and cancellation

    DOE Patents [OSTI]

    Goff, David R. (Star City, WV); Notestein, John E. (Morgantown, WV)

    1986-01-01

    A fiber optics based optical emission line monitoring system is provided in which selected spectral emission lines, such as the sodium D-line emission in coal combustion, may be detected in the presence of interferring background or blackbody radiation with emissions much greater in intensity than that of the emission line being detected. A bifurcated fiber optic light guide is adapted at the end of one branch to view the combustion light which is guided to a first bandpass filter, adapted to the common trunk end of the fiber. A portion of the light is reflected back through the common trunk portion of the fiber to a second bandpass filter adapted to the end of the other branch of the fiber. The first filter bandpass is centered at a wavelength corresponding to the emission line to be detected with a bandwidth of about three nanometers (nm). The second filter is centered at the same wavelength but having a width of about 10 nm. First and second light detectors are located to view the light passing through the first and second filters respectively. Thus, the second detector is blind to the light corresponding to the emission line of interest detected by the first detector and the difference between the two detector outputs is uniquely indicative of the intensity of only the combustion flame emission of interest. This instrument can reduce the effects of interferring blackbody radiation by greater than 20 dB.

  11. Low-Mass X-Ray Binary MAXI J1421-613 Observed by MAXI GSC and Swift XRT

    E-Print Network [OSTI]

    Serino, Motoko; Ueda, Yoshihiro; Matsuoka, Masaru; Negoro, Hitoshi; Yamaoka, Kazutaka; Kennea, Jamie A; Fukushima, Kosuke; Nagayama, Takahiro

    2015-01-01

    Monitor of All sky X-ray Image (MAXI) discovered a new outburst of an X-ray transient source named MAXI J1421-613. Because of the detection of three X-ray bursts from the source, it was identified as a neutron star low-mass X-ray binary. The results of data analyses of the MAXI GSC and the Swift XRT follow-up observations suggest that the spectral hardness remained unchanged during the first two weeks of the outburst. All the XRT spectra in the 0.5-10 keV band can be well explained by thermal Comptonization of multi-color disk blackbody emission. The photon index of the Comptonized component is $\\approx$ 2, which is typical of low-mass X-ray binaries in the low/hard state. Since X-ray bursts have a maximum peak luminosity, it is possible to estimate the (maximum) distance from its observed peak flux. The peak flux of the second X-ray burst, which was observed by the GSC, is about 5 photons cm$^{-2}$ s$^{-1}$. By assuming a blackbody spectrum of 2.5 keV, the maximum distance to the source is estimated as 7 kpc...

  12. Optical emission line monitor with background observation and cancellation

    DOE Patents [OSTI]

    Goff, D.R.; Notestein, J.E.

    1985-01-04

    A fiber optics based optical emission line monitoring system is provided in which selected spectral emission lines, such as the sodium D-line emission in coal combustion, may be detected in the presence of interferring background or blackbody radiation with emissions much greater in intensity than that of the emission line being detected. A bifurcated fiber optic light guide is adapted at the end of one branch to view the combustion light which is guided to a first bandpass filter, adapted to the common trunk end of the fiber. A portion of the light is reflected back through the common trunk portion of the fiber to a second bandpass filter adapted to the end of the other branch of the fiber. The first filter bandpass is centered at a wavelength corresponding to the emission line to be detected with a bandwidth of about three nanometers (nm). The second filter is centered at the same wavelength but having a width of about 10 nm. First and second light detectors are located to view the light passing through the first and second filters respectively. Thus, the second detector is blind to the light corresponding to the emission line of interest detected by the first detector and the difference between the two detector outputs is uniquely indicative of the intensity of only the combustion flame emission of interest. This instrument can reduce the effects of interfering blackbody radiation by greater than 20 dB.

  13. Suzaku observation of the classical nova V2491 Cyg in quiescence

    E-Print Network [OSTI]

    Zemko, Polina; Orio, Marina

    2015-01-01

    We present Suzaku XIS observation of V2491 Cyg (Nova Cyg 2008 No. 2) obtained in quiescence, more than two years after the outburst. The nova was detected as a very luminous source in a wide spectral range from soft to hard X-rays. A very soft blackbody-like component peaking at 0.5 keV indicates that either we observe remaining, localized hydrogen burning on the surface of the white dwarf, or accretion onto a magnetized polar cap. In the second case, V2491 Cyg is a candidate "soft intermediate polar". We obtained the best fit for the X-ray spectra with several components: two of thermal plasma, a blackbody and a complex absorber. The later is typical of intermediate polars. The X-ray light-curve shows a modulation with a $\\sim$38 min period. The amplitude of this modulation is strongly energy dependent and reaches maximum in the 0.8--2.0 keV range. We discuss the origin of the X-ray emission and pulsations, and the likelihood of the intermediate polar scenario.

  14. NuSTAR OBSERVATIONS OF THE MAGNETAR 1E 2259+586

    SciTech Connect (OSTI)

    Vogel, Julia K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hascoët, Romain [Columbia Univ., New York, NY (United States); Kaspi, Victoria M. [Univ. of Montreal, Quebec (Canada); An, Hongjun [Univ. of Montreal, Quebec (Canada); Archibald, Robert [Univ. of Montreal, Quebec (Canada); Beloborodov, Andrei M. [Columbia Univ., New York, NY (United States); Boggs, Steven E. [Univ. of California, Berkeley, CA (United States); Christensen, Finn E. [Technical Univ. of Denmark, Lyngby (Denmark); Craig, William W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Gotthelf, Eric V. [Columbia Univ., New York, NY (United States); Grefenstette, Brian W. [California Inst. of Technology (CalTech), Pasadena, CA (United States); Hailey, Charles J. [Columbia Univ., New York, NY (United States); Harrison, Fiona A. [California Inst. of Technology (CalTech), Pasadena, CA (United States); Kennea, Jamie A. [Pennsylvania State Univ., State College, PA (United States); Madsen, Kristin K. [California Inst. of Technology (CalTech), Pasadena, CA (United States); Pivovaroff, Michael J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Stern, Daniel [California Inst. of Technology (CalTech), Pasadena, CA (United States); Zhang, William W. [NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States)

    2014-07-01

    We report on new broad band spectral and temporal observations of the magnetar 1E 2259+586, which is located in the supernova remnant CTB 109. Our data were obtained simultaneously with the Nuclear Spectroscopic Telescope Array (NuSTAR) and Swift, and cover the energy range from 0.5-79 keV. We present pulse profiles in various energy bands and compare them to previous RXTE results. The NuSTAR data show pulsations above 20 keV for the first time and we report evidence that one of the pulses in the double-peaked pulse profile shifts position with energy. The pulsed fraction of the magnetar is shown to increase strongly with energy. Our spectral analysis reveals that the soft X-ray spectrum is well characterized by an absorbed double blackbody or blackbody plus power-law model in agreement with previous reports. Our new hard X-ray data, however, suggest that an additional component, such as a power law, is needed to describe the NuSTAR and Swift spectrum. We also fit the data with the recently developed coronal outflow model by Beloborodov for hard X-ray emission from magnetars. The outflow from a ring on the magnetar surface is statistically preferred over outflow from a polar cap.

  15. A remarkable recurrent nova in M 31: The predicted 2014 outburst in X-rays with Swift

    E-Print Network [OSTI]

    Henze, M; Darnley, M J; Bode, M F; Williams, S C; Shafter, A W; Sala, G; Kato, M; Hachisu, I; Hernanz, M

    2015-01-01

    The M 31 nova M31N 2008-12a was recently found to be a recurrent nova (RN) with a recurrence time of about 1 year. This is by far the fastest recurrence time scale of any known RNe. Our optical monitoring programme detected the predicted 2014 outburst of M31N 2008-12a in early October. We immediately initiated an X-ray/UV monitoring campaign with Swift to study the multiwavelength evolution of the outburst. We monitored M31N 2008-12a with daily Swift observations for 20 days after discovery, covering the entire supersoft X-ray source (SSS) phase. We detected SSS emission around day six after outburst. The SSS state lasted for approximately two weeks until about day 19. M31N 2008-12a was a bright X-ray source with a high blackbody temperature. The X-ray properties of this outburst were very similar to the 2013 eruption. Combined X-ray spectra show a fast rise and decline of the effective blackbody temperature. The short-term X-ray light curve showed strong, aperiodic variability which decreased significantly a...

  16. Photon-induced Nucleosynthesis: Current Problems and Experimental Approaches

    E-Print Network [OSTI]

    P. Mohr; Zs. Fulop; H. Utsunomiya

    2007-05-16

    Photon-induced reactions play a key role in the nucleosynthesis of rare neutron-deficient p-nuclei. The paper focuses on (gamma,alpha), (gamma,p), and (gamma,n) reactions which define the corresponding p-process path. The relation between stellar reaction rates and laboratory cross sections is analyzed for photon-induced reactions and their inverse capture reactions to evaluate various experimental approaches. An improved version S_C(E) of the astrophysical S-factor is suggested which is based on the Coulomb wave functions. S_C(E) avoids the apparent energy dependence which is otherwise obtained for capture reactions on heavy nuclei. It is found that a special type of synchrotron radiation available at SPring-8 that mimics stellar blackbody radiation at billions of Kelvin is a promising tool for future experiments. By using the blackbody synchrotron radiation, sufficient event rates for (gamma,alpha) and (gamma,p) reactions in the p-process path can be expected. These experiments will provide data to improve the nuclear parameters involved in the statistical model and thus reduce the uncertainties of nucleosynthesis calculations.

  17. Science Overview Document Indirect and Semi-Direct Aerosol Campaign (ISDAC) April 2008

    SciTech Connect (OSTI)

    SJ Ghan; B Schmid; JM Hubbe; CJ Flynn; A Laskin; AA Zelenyuk; DJ Czizco; CN Long; G McFarquhar; J Verlinde; J Harrington; JW Strapp; P Liu; A Korolev; A McDonald; M Wolde; A Fridlind; T Garrett; G Mace; G Kok; S Brooks; D Collins; D Lubin; P Lawson; M Dubey; C Mazzoleni; M Shupe; S Xie; DD Turner; Q Min; EJ Mlawer; D Mitchell

    2007-11-01

    The ARM Climate Research Facility’s (ACRF) Aerial Vehicle Program (AVP) will deploy an intensive cloud and aerosol observing system to the ARM North Slope of Alaska (NSA) locale for a five week Indirect and Semi-Direct Aerosol Campaign (ISDAC) during period 29 March through 30 April 2008. The deployment period is within the International Polar Year, thus contributing to and benefiting from the many ancillary observing systems collecting data synergistically. We will deploy the Canadian National Research Council Convair 580 aircraft to measure temperature, humidity, total particle number, aerosol size distribution, single particle composition, concentrations of cloud condensation nuclei and ice nuclei, optical scattering and absorption, updraft velocity, cloud liquid water and ice contents, cloud droplet and crystal size distributions, cloud particle shape, and cloud extinction. In addition to these aircraft measurements, ISDAC will deploy two instruments at the ARM site in Barrow: a spectroradiometer to retrieve cloud optical depth and effective radius, and a tandem differential mobility analyzer to measure the aerosol size distribution and hygroscopicity. By using many of the same instruments used during Mixed-Phase Arctic Cloud Experiment (M-PACE), conducted in October 2004, we will be able to contrast the arctic aerosol and cloud properties during the fall and spring transitions. The aerosol measurements can be used in cloud models driven by objectively analyzed boundary conditions to test whether the cloud models can simulate the aerosol influence on the clouds. The influence of aerosol and boundary conditions on the simulated clouds can be separated by running the cloud models with all four combinations of M-PACE and ISDAC aerosol and boundary conditions: M-PACE aerosol and boundary conditions, M-PACE aerosol and ISDAC boundary conditions, ISDAC aerosol and M-PACE boundary conditions, and ISDAC aerosol and boundary conditions. ISDAC and M-PACE boundary conditions are likely to be very different because of the much more extensive ocean water during M-PACE. The uniformity of the surface conditions during ISDAC greatly simplifies the objective analysis (surface fluxes and precipitation are very weak), so that it can largely rely on the European Centre for Medium-Range Weather Forecasts analysis. The aerosol measurements can also be used as input to the cloud models and to evaluate the aerosol retrievals. By running the cloud models with and without solar absorption by the aerosols, we can determine the semidirect effect of the aerosol on the clouds.

  18. Equivalence of optical and electrical noise equivalent power of hybrid NbTiN-Al microwave kinetic inductance detectors

    SciTech Connect (OSTI)

    Janssen, R. M. J.; Endo, A.; Visser, P. J. de; Klapwijk, T. M.; Baselmans, J. J. A.

    2014-11-10

    We have measured and compared the response of hybrid NbTiN-Al Microwave Kinetic Inductance Detectors (MKIDs) to changes in bath temperature and illumination by sub-mm radiation. We show that these two stimulants have an equivalent effect on the resonance feature of hybrid MKIDs. We determine an electrical noise equivalent power (NEP) from the measured temperature responsivity, quasiparticle recombination time, superconducting transition temperature, and noise spectrum, all of which can be measured in a dark environment. For the two hybrid NbTiN-Al MKIDs studied in detail, the electrical NEP is within a factor of two of the optical NEP, which is measured directly using a blackbody source.

  19. A soft x-ray transmission grating imaging-spectrometer for the National Ignition Facility

    SciTech Connect (OSTI)

    Moore, A S; Guymer, T M; Kline, J L; Morton, J; Taccetti, M; Lanier, N E; Bentley, C; Workman, J; Peterson, B; Mussack, K; Cowan, J; Prasad, R; Richardson, M; Burns, S; Kalantar, D H; Benedetti, L R; Bell, P; Bradley, D; Hsing, W; Stevenson, M

    2012-05-01

    A soft x-ray transmission grating spectrometer has been designed for use on high energy-density physics experiments at the National Ignition Facility (NIF); coupled to one of the NIF gated x-ray detectors (GXD) it records sixteen time-gated spectra between 250 and 1000eV with 100ps temporal resolution. The trade-off between spectral and spatial resolution leads to an optimized design for measurement of emission around the peak of a 100-300eV blackbody spectrum. Performance qualification results from the NIF, the Trident Laser Facility and VUV beamline at the National Synchrotron Light Source (NSLS), evidence a <100{micro}m spatial resolution in combination with a source-size limited spectral resolution that is <10eV at photon energies of 300eV.

  20. Distance determination to eight galaxies using expanding photosphere method

    SciTech Connect (OSTI)

    Bose, Subhash; Kumar, Brijesh, E-mail: email@subhashbose.com, E-mail: bose@aries.res.in [Aryabhatta Research Institute of Observational Sciences, Manora Peak, Nainital 263002 (India)

    2014-02-20

    Type IIP supernovae (SNe) are recognized as independent extragalactic distance indicators; however, keeping in mind the diverse nature of their observed properties as well as the availability of good quality data, more and newer events need to be tested for their applicability as reliable distance indicators. We use early photometric and spectroscopic data of eight Type IIP SNe to derive distances to their host galaxies by using the expanding photosphere method (EPM). For five of these, the EPM is applied for the first time. In this work, we improved EPM application by using SYNOW estimated velocities and by semi-deconvolving the broadband filter responses while deriving color temperatures and blackbody angular radii. We find that the derived EPM distances are consistent with that derived using other redshift-independent methods.

  1. A Flat Universe from High-Resolution Maps of the Cosmic Microwave Background Radiation

    E-Print Network [OSTI]

    P. de Bernardis; P. A. R. Ade; J. J. Bock; J. R. Bond; J. Borrill; A. Boscaleri; K. Coble; B. P. Crill; G. De Gasperis; P. C. Farese; P. G. Ferreira; K. Ganga; M. Giacometti; E. Hivon; V. V. Hristov; A. Iacoangeli; A. H. Jaffe; A. E. Lange; L. Martinis; S. Masi; P. Mason; P. D. Mauskopf; A. Melchiorri; L. Miglio; T. Montroy; C. B. Netterfield; E. Pascale; F. Piacentini; D. Pogosyan; S. Prunet; S. Rao; G. Romeo; J. E. Ruhl; F. Scaramuzzi; D. Sforna; N. Vittorio

    2000-04-28

    The blackbody radiation left over from the Big Bang has been transformed by the expansion of the Universe into the nearly isotropic 2.73K Cosmic Microwave Background. Tiny inhomogeneities in the early Universe left their imprint on the microwave background in the form of small anisotropies in its temperature. These anisotropies contain information about basic cosmological parameters, particularly the total energy density and curvature of the universe. Here we report the first images of resolved structure in the microwave background anisotropies over a significant part of the sky. Maps at four frequencies clearly distinguish the microwave background from foreground emission. We compute the angular power spectrum of the microwave background, and find a peak at Legendre multipole $\\ell_{peak}=(197 \\pm 6)$, with an amplitude $DT_{200}=(69 \\pm 8)\\mu K$. This is consistent with that expected for cold dark matter models in a flat (euclidean) Universe, as favoured by standard inflationary scenarios.

  2. Monochromatic x-ray imaging experiments on the Sandia National Laboratories Z facility (invited)

    SciTech Connect (OSTI)

    Sinars, D.B.; Bennett, G.R.; Wenger, D.F.; Cuneo, M.E.; Hanson, D.L.; Porter, J.L.; Adams, R.G.; Rambo, P.K.; Rovang, D.C.; Smith, I.C.

    2004-10-01

    The Z facility is a 20 MA, 100 ns rise time, pulsed power driver for z-pinch plasma radiation sources. The Z facility can make >200 TW, 1-2 MJ, near-blackbody radiation sources through the compression of cylindrical wire arrays. These sources are being used as drivers to study inertial-confinement fusion capsule implosions, complex radiation-hydrodynamic jet experiments, and wire-array z-pinch physics tests. To backlight plasmas in this environment we have built diagnostics based on spherically bent crystals that provide high spatial resolution (9-10 {mu}m), a narrow spectral bandpass (<0.5 eV), and a large field of view (4 mmx20 mm). These diagnostics use the 2 TW, multi-kJ Z-Beamlet laser to produce x-ray emission sources at 1.865 or 6.151 keV for backlighting.

  3. A comparison of irradiance responsivity and thermodynamic temperature measurement between PTB and NIM

    SciTech Connect (OSTI)

    Lu, X.; Yuan, Z.; Anhalt, K.; Taubert, R. D.

    2013-09-11

    This paper describes a comparison between PTB and NIM in the field of absolute spectral-band radiometry and thermodynamic temperature measurement. For the comparison a NIM made interference filter radiometer with a centre wavelength of 633 nm was taken to PTB. The filter radiometer was calibrated at NIM and PTB with respect to spectral irradiance responsivity. For the integral value in the band-pass range an agreement of 0.1% was observed in both calibrations. In a next step, the 633 nm filter radiometer was used to measure the temperature of a high-temperature blackbody in comparison to an 800 nm filter radiometer of PTB in the temperature range between 1400 K and 2750 K. The thermodynamic temperature measured by the two filter radiometers agreed to within 0.2 K to 0.5 K with an estimated measurement uncertainty ranging between 0.1 K and 0.4 K (k=1)

  4. Spectral Resolution for Five-Element, Filtered, X-Ray Detector (XRD) Arrays Using the Methods of Backus and Gilbert

    SciTech Connect (OSTI)

    FEHL,DAVID LEE; BIGGS,F.; CHANDLER,GORDON A.; STYGAR,WILLIAM A.

    2000-01-17

    The generalized method of Backus and Gilbert (BG) is described and applied to the inverse problem of obtaining spectra from a 5-channel, filtered array of x-ray detectors (XRD's). This diagnostic is routinely fielded on the Z facility at Sandia National Laboratories to study soft x-ray photons ({le}2300 eV), emitted by high density Z-pinch plasmas. The BG method defines spectral resolution limits on the system of response functions that are in good agreement with the unfold method currently in use. The resolution so defined is independent of the source spectrum. For noise-free, simulated data the BG approximating function is also in reasonable agreement with the source spectrum (150 eV black-body) and the unfold. This function may be used as an initial trial function for iterative methods or a regularization model.

  5. High efficiency rare-earth emitter for thermophotovoltaic applications

    SciTech Connect (OSTI)

    Sakr, E. S.; Zhou, Z.; Bermel, P., E-mail: pbermel@purdue.edu [Birck Nanotechnology Center, School of Electrical and Computer Engineering, Purdue University, 1205 W. State St., West Lafayette, Indiana 47907 (United States)

    2014-09-15

    In this work, we propose a rare-earth-based ceramic thermal emitter design that can boost thermophotovoltaic (TPV) efficiencies significantly without cold-side filters at a temperature of 1573?K (1300?°C). The proposed emitter enhances a naturally occurring rare earth transition using quality-factor matching, with a quarter-wave stack as a highly reflective back mirror, while suppressing parasitic losses via exponential chirping of a multilayer reflector transmitting only at short wavelengths. This allows the emissivity to approach the blackbody limit for wavelengths overlapping with the absorption peak of the rare-earth material, while effectively reducing the losses associated with undesirable long-wavelength emission. We obtain TPV efficiencies of 34% using this layered design, which only requires modest index contrast, making it particularly amenable to fabrication via a wide variety of techniques, including sputtering, spin-coating, and plasma-enhanced chemical vapor deposition.

  6. Ultimate low system dark count rate for superconducting nanowire single-photon detector

    E-Print Network [OSTI]

    Hiroyuki Shibata; Kaoru Shimizu; Hiroki Takesue; Yasuhiro Tokura

    2015-07-07

    The dark count rate (DCR) is a key parameter of single-photon detectors. By introducing a bulk optical band-pass filter mounted on a fiber-to-fiber optical bench cooled at 3 K and blocking down to 5 micrometer, we suppressed the DCR of a superconducting nanowire single-photon detector by more than three orders of magnitude. The DCR is limited by the blackbody radiation through a signal passband of 20 nm bandwidth. The figure of merit, system detection efficiency, and DCR were 2.7 x 10^11, 2.3 %, and 0.001 Hz, respectively. Narrowing the bandwidth to 100 GHz suppresses the DCR to 0.0001 Hz and the figure of merit increases to 1.8 x 10^12.

  7. Importance of Compton scattering to radiation spectra of isolated neutron stars

    E-Print Network [OSTI]

    V. Suleimanov; K. Werner

    2006-12-22

    Model atmospheres of isolated neutron stars with low magnetic field are calculated with Compton scattering taking into account. Models with effective temperatures 1, 3 and 5 MK, with two values of surface gravity log(g)g = 13.9 and 14.3), and different chemical compositions are calculated. Radiation spectra computed with Compton scattering are softer than the computed with Thomson scattering at high energies (E > 5 keV) for hot (T_eff > 1 MK) atmospheres with hydrogen-helium composition. Compton scattering is more significant to hydrogen models with low surface gravity. The emergent spectra of the hottest (T_eff > 3 MK) model atmospheres can be described by diluted blackbody spectra with hardness factors ~ 1.6 - 1.9. Compton scattering is less important for models with solar abundance of heavy elements.

  8. Ultimate low system dark count rate for superconducting nanowire single-photon detector

    E-Print Network [OSTI]

    Shibata, Hiroyuki; Takesue, Hiroki; Tokura, Yasuhiro

    2015-01-01

    The dark count rate (DCR) is a key parameter of single-photon detectors. By introducing a bulk optical band-pass filter mounted on a fiber-to-fiber optical bench cooled at 3 K and blocking down to 5 micrometer, we suppressed the DCR of a superconducting nanowire single-photon detector by more than three orders of magnitude. The DCR is limited by the blackbody radiation through a signal passband of 20 nm bandwidth. The figure of merit, system detection efficiency, and DCR were 2.7 x 10^11, 2.3 %, and 0.001 Hz, respectively. Narrowing the bandwidth to 100 GHz suppresses the DCR to 0.0001 Hz and the figure of merit increases to 1.8 x 10^12.

  9. Confronting GRB prompt emission with a model for subphotospheric dissipation

    E-Print Network [OSTI]

    Ahlgren, Björn; Nymark, Tanja; Ryde, Felix; Pe'er, Asaf

    2015-01-01

    The origin of the prompt emission in gamma-ray bursts (GRBs) is still an unsolved problem and several different mechanisms have been suggested. Here we fit Fermi GRB data with a photospheric emission model which includes dissipation of the jet kinetic energy below the photosphere. The resulting spectra are dominated by Comptonization and contain no significant contribution from synchrotron radiation. In order to fit to the data we span a physically motivated part of the model's parameter space and create DREAM ($\\textit{Dissipation with Radiative Emission as A table Model}$), a table model for ${\\scriptsize XSPEC}$. We show that this model can describe different kinds of GRB spectra, including GRB 090618, representing a typical Band function spectrum, and GRB 100724B, illustrating a double peaked spectrum, previously fitted with a Band+blackbody model, suggesting they originate from a similar scenario. We suggest that the main difference between these two types of bursts is the optical depth at the dissipatio...

  10. Our distorted view of magnetars: application of the Resonant Cyclotron Scattering model

    E-Print Network [OSTI]

    N. Rea; S. Zane; M. Lyutikov; R. Turolla

    2006-08-30

    The X-ray spectra of the magnetar candidates are customarily fitted with an empirical, two component model: an absorbed blackbody and a power-law. However, the physical interpretation of these two spectral components is rarely discussed. It has been recently proposed that the presence of a hot plasma in the magnetosphere of highly magnetized neutron stars might distort, through efficient resonant cyclotron scattering, the thermal emission from the neutron star surface, resulting in the production of non-thermal spectra. Here we discuss the Resonant Cyclotron Scattering (RCS) model, and present its XSPEC implementation, as well as preliminary results of its application to Anomalous X-ray Pulsars and Soft Gamma-ray Repeaters.

  11. Low-Energy X-ray Emission from Young Isolated Neutron Stars

    E-Print Network [OSTI]

    M. Ruderman

    2003-10-28

    A young neutron star with large spin-down power is expected to be closely surrounded by an e+/- pair plasma maintained by the conversion of gamma-rays associated with the star's polar-cap and/or outer-gap accelerators. Cyclotron-resonance scattering by the e- and e+ within several radii of such neutron stars prevents direct observations of thermal X-rays from the stellar surface. Estimates are presented for the parameters of the Planck-like X-radiation which ultimately diffuses out through this region. Comparisons with observations, especially of apparent blackbody emission areas as a function of neutron star age, support the proposition that we are learning about a neutron star's magnetosphere rather than about its surface from observations of young neutron star thermal X-rays.

  12. Firewalls, black-hole thermodynamics, and singular solutions of the Tolman-Oppenheimer-Volkoff equation

    E-Print Network [OSTI]

    Zurek, Wojciech H

    2015-01-01

    We investigate thermodynamic equilibrium of a self-gravitating perfect fluid in a spherically symmetric system containing a black hole of mass M by means of the Tolman-Oppenheimer-Volkoff (TOV) equation. At r >> 2M its solutions describe a black-body radiation atmosphere with the Hawking temperature T_BH~1/(8 \\pi M) that is increasingly blueshifted as r approaches 2M. However, there is no horizon at the Schwarzschild radius. Instead, the fluid becomes increasingly hot and dense there, piling up into a "firewall" with the peak temperatures and densities reaching Planck values somewhat below r = 2M. This firewall surrounds a negative point mass residing at r=0, the only singularity of the solution. The entropy of the firewall is comparable to the Bekenstein-Hawking entropy.

  13. The Big Bang, COBE, and the Relic Radiation of Creation (LBNL Science at the Theater)

    ScienceCinema (OSTI)

    Smoot, George

    2011-04-28

    Berkeley Lab's George Smoot won the 2006 Physics Nobel Prize, together with John Mather of NASA Goddard Space Flight Center, for "the discovery of the blackbody form and anisotropy of the cosmic microwave background radiation." The anisotropy showed as small variations in the map of the early universe. This research looks back into the infant universe and provides a better understanding of the origin of galaxies and stars. The cosmic background radiation is a tool to understand the structure and history of the universe and the structure of space-time. These observations have provided increased support for the big bang theory of the universe's origin. The Cosmic Background Explorer (COBE) NASA satellite, launched in 1989, carries instruments that measured various aspects of cosmic microwave background radiation, and produced the data for these compelling scientific results, which opened up a field that continues very actively today.

  14. A Young White Dwarf with an Infrared Excess

    E-Print Network [OSTI]

    Xu, S; Pantoja, B; Klein, B; Zuckerman, B; Su, K Y L; Meng, H Y A

    2015-01-01

    Using observations of Spitzer/IRAC, we report the serendipitous discovery of excess infrared emission from a single white dwarf PG 0010+280. At a temperature of 27,220 K and a cooling age of 16 Myr, it is the hottest and youngest white dwarf to display an excess at 3-8 $\\mu$m. The infrared excess can be fit by either an opaque dust disk within the tidal radius of the white dwarf or a 1300 K blackbody, possibly from an irradiated substellar object or a re-heated giant planet. PG 0010+280 has two unique properties that are different from white dwarfs with a dust disk: (i) relatively low emission at 8 $\\mu$m and (ii) non-detection of heavy elements in its atmosphere from high-resolution spectroscopic observations with Keck/HIRES. The origin of the infrared excess remains unclear.

  15. Functional Form of the Imaginary Part of the Atomic Polarizability

    E-Print Network [OSTI]

    U. D. Jentschura; K. Pachucki

    2015-04-21

    The dynamic atomic polarizability describes the response of the atom to incoming electromagnetic radiation. The functional form of the imaginary part of the polarizability for small driving frequencies omega has been a matter of long-standing discussion, with both a linear dependence and an omega^3 dependence being presented as candidate formulas. The imaginary part of the polarizability enters the expressions of a number of fundamental physical processes which involve the thermal dissipation of energy, such as blackbody friction, and non-contact friction. Here, we solve the long-standing problem by calculating the imaginary part of the polarizability in both the length (d.E) as well as the velocity-gauge (p.A) form of the dipole interaction, verify the gauge invariance, and find general expressions applicable to atomic theory; the omega^3 form is obtained in both gauges. The seagull term in the velocity gauge is found to be crucial in establishing gauge invariance.

  16. Measurement of the large-scale anisotropy of the cosmic background radiation at 3mm

    SciTech Connect (OSTI)

    Epstein, G.L.

    1983-12-01

    A balloon-borne differential radiometer has measured the large-scale anisotropy of the cosmic background radiation (CBR) with high sensitivity. The antenna temperature dipole anistropy at 90 GHz (3 mm wavelength) is 2.82 +- 0.19 mK, corresponding to a thermodynamic anistropy of 3.48 +- mK for a 2.7 K blackbody CBR. The dipole direction, 11.3 +- 0.1 hours right ascension and -5.7/sup 0/ +- 1.8/sup 0/ declination, agrees well with measurements at other frequencies. Calibration error dominates magnitude uncertainty, with statistical errors on dipole terms being under 0.1 mK. No significant quadrupole power is found, placing a 90% confidence-level upper limit of 0.27 mK on the RMS thermodynamic quadrupolar anistropy. 22 figures, 17 tables.

  17. Detecting the cosmological recombination signal from space

    E-Print Network [OSTI]

    Desjacques, Vincent; Silk, Joseph; de Bernardis, Francesco; Doré, Olivier

    2015-01-01

    Spectral distortions of the CMB have recently experienced an increased interest. One of the inevitable distortion signals of our cosmological concordance model is created by the cosmological recombination process, just a little before photons last scatter at redshift $z\\simeq 1100$. These cosmological recombination lines, emitted by the hydrogen and helium plasma, should still be observable as tiny deviation from the CMB blackbody spectrum in the cm--dm spectral bands. In this paper, we present a forecast for the detectability of the recombination signal with future satellite experiments. We argue that serious consideration for future CMB experiments in space should be given to probing spectral distortions and, in particular, the recombination line signals. The cosmological recombination radiation not only allows determination of standard cosmological parameters, but also provides a direct observational confirmation for one of the key ingredients of our cosmological model: the cosmological recombination histo...

  18. Temperature Measurement during Thermonuclear X-ray Bursts with BeppoSAX

    E-Print Network [OSTI]

    Beri, Aru; Orlandini, Mauro; Maitra, Chandreyee

    2015-01-01

    We have carried out a study of temperature evolution during thermonuclear bursts in LMXBs using broad band data from two instruments onboard BeppoSAX, the MECS and the PDS. However, instead of applying the standard technique of time resolved spectroscopy, we have determined the temperature in small time intervals using the ratio of count rates in the two instruments assuming a blackbody nature of burst emission and different interstellar absorption for different sources. Data from a total of twelve observations of six sources were analysed during which 22 bursts were detected. We have obtained temperatures as high as ~3.0 keV, even when there is no evidence of photospheric radius expansion. These high temperatures were observed in the sources within different broadband spectral states (soft and hard).

  19. Magnetized Atmospheres around Accreting Neutron Stars

    E-Print Network [OSTI]

    S. Zane; R. Turolla; A. Treves

    2000-02-01

    We present a detailed investigation of atmospheres around accreting neutron stars with high magnetic field ($B\\gtrsim 10^{12}$ G) and low luminosity ($L\\lesssim 10^{33}$ erg/s). We compute the atmospheric structure, intensity and emergent spectrum for a plane-parallel, pure hydrogen medium by solving the transfer equations for the normal modes coupled to the hydrostatic and energy balance equations. The hard tail found in previous investigations for accreting, non-magnetic neutron stars with comparable luminosity is suppressed and the X-ray spectrum, although still harder than a blackbody at the star effective temperature, is nearly planckian in shape. Spectra from accreting atmospheres, both with high and low fields, are found to exhibit a significant excess at optical wavelengths above the Rayleigh-Jeans tail of the X-ray continuum.

  20. High detectivity short-wavelength II-VI quantum cascade detector

    SciTech Connect (OSTI)

    Ravikumar, Arvind P. Gmachl, Claire F.; Garcia, Thor A.; Tamargo, Maria C.; Jesus, Joel De

    2014-08-11

    We report on the experimental demonstration of a ZnCdSe/ZnCdMgSe-based short-wavelength photovoltaic Quantum Cascade Detector (QCD). The QCD operates in two spectral bands centered around 2.6??m and 3.6??m. Calibrated blackbody measurements yield a peak responsivity of 0.1?mA/W or 2400?V/W at 80?K, and a corresponding 300?K background radiation limited infrared performance detectivity (BLIP) of ?2.5?×?10{sup 10?}cm ?Hz/W. Comparison of background illuminated and dark current-voltage measurements demonstrates a BLIP temperature of 200?K. The device differential resistance-area product, decreases from about 10{sup 6} ? cm{sup 2} at 80?K to about 8000 ? cm{sup 2} at 300?K, indicative of the ultra-low Johnson noise in the detectors.

  1. Extraordinary Photon Transport by Near-Field Coupling of a Nanostructured Metamaterial with a Graphene-Covered Plate

    E-Print Network [OSTI]

    Chang, Jui-Yung; Wang, Liping

    2015-01-01

    Coupled surface plasmon/phonon polaritons and hyperbolic modes are known to enhance radiative transport across nanometer vacuum gaps but usually require identical materials. It becomes crucial to achieve strong near-field energy transfer between dissimilar materials for applications like near-field thermophotovoltaic and thermal rectification. In this work, we theoretically demonstrate extraordinary near-field radiative transport between a nanostructured metamaterial emitter and a graphene-covered planar receiver. Strong near-field coupling with two orders of magnitude enhancement in the spectral heat flux is achieved at the gap distance of 20 nm. By carefully selecting the graphene chemical potential and doping levels of silicon nanohole emitter and silicon plate receiver, the total near-field radiative heat flux can reach about 500 times higher than the far-field blackbody limit between 400 K and 300 K. The physical mechanisms are elucidated by the near-field surface plasmon coupling with fluctuational elec...

  2. Sensitivity of Biosignatures on Earth-like Planets orbiting in the Habitable Zone of Cool M-Dwarf Stars to varying Stellar UV Radiation and Surface Biomass Emissions

    E-Print Network [OSTI]

    Grenfell, John Lee; von Paris, Philip; Godolt, Mareike; Rauer, Heike

    2015-01-01

    We find that variations in the UV emissions of cool M-dwarf stars have a potentially large impact upon atmospheric biosignatures in simulations of Earth-like exoplanets i.e. planets with Earths development, and biomass and a molecular nitrogen-oxygen dominated atmosphere. Starting with an assumed black-body stellar emission for an M7 class dwarf star, the stellar UV irradiation was increased stepwise and the resulting climate-photochemical response of the planetary atmosphere was calculated. Results suggest a Goldilocks effect with respect to the spectral detection of ozone. At weak UV levels, the ozone column was weak (due to weaker production from the Chapman mechanism) hence its spectral detection was challenging. At strong UV levels, ozone formation is stronger but its associated stratospheric heating leads to a weakening in temperature gradients between the stratosphere and troposphere, which results in weakened spectral bands. Also, increased UV levels can lead to enhanced abundances of hydrogen oxides ...

  3. Soft X-ray spectral variability of AM Herculis

    E-Print Network [OSTI]

    K. Beuermann; E. El Kholy; K. Reinsch

    2008-02-19

    Polars (AM Herculis binaries) are a prominent class of bright soft X-ray sources, many of which were discovered with ROSAT. We present a homogenous analysis of all the pointed ROSAT PSPC observations of polars subdivided into two papers that discuss the prototype polar AM Her in detail and summarize the class properties of all other polars. We derive the high-state soft X-ray flux and short-term spectral variability of AM Her using a new detector response matrix and a confirmed flux calibration of the ROSAT PSPC below 0.28 keV. The best-fit mean single-blackbody temperature and integrated bright-phase energy flux of AM Her in its April 1991 high state are 27.2 +/- 1.0 eV and (2.6 +/- 0.6) x 10^-9 erg cm^-2s^-1, respectively. The total blackbody flux of a multi-temperature model that fits both the soft X-ray and the fluctuating far-ultraviolet components is Fbb = (4.5 +/- 1.5) x 10^-9 erg cm^-2s^-1. The total accretion luminosity at a distance of 80 pc, Lbb = (2.1 +/- 0.7) x 10^33 erg s-1, implies an accretion rate of Mdot = (2.4 +/- 0.8) x 10^-10 Msun yr^-1 for an 0.78 Msun white dwarf. The soft X-ray flux displays significant variability on time scales down to 200 ms. Correlated spectral and count-rate variations are seen in flares on time scales down to 1 s, demonstrating the heating and cooling associated with individual accretion events. Our spectral and temporal analysis provides direct evidence for the blobby accretion model and suggests a connection between the soft X-ray and the fluctuating far-ultraviolet components.

  4. Bare Quark Stars or Naked Neutron Stars ? The Case of RX J1856.5-3754

    E-Print Network [OSTI]

    Roberto Turolla; Silvia Zane; Jeremy J. Drake

    2003-11-21

    In a cool neutron star (T 1.e13 G), a phase transition may occur in the outermost layers. As a consequence the neutron star becomes `bare', i.e. no gaseous atmosphere sits on the top of the crust. The surface of a cooling, bare neutron star does not necessarily emit a blackbody spectrum because the emissivity is strongly suppressed at energies below the electron plasma frequency, omega_p. Since omega_p ~ 1 keV under the conditions typical of the denseelectron gas in the condensate, the emission from a T ~ 100 eV bare neutron star will be substantially depressed with respect to that of a perfect Planckian radiator at most energies. Here we present a detailed analysis of the emission properties of a bare neutron star. In particular, we derive the surface emissivity for a Fe composition in a range of magnetic fields and temperatures representative of cooling isolated neutron stars, like RX J1856.5-3754. We find that the emitted spectrum is strongly dependent on the electron conductivity in the solid surface layers. In the cold electron gas approximation (no electron-lattice interactions), the spectrum turns out to be a featureless depressed blackbody in the 0.1-2 keV band with a steeper low-energy distribution. When damping effects due to collisions between electrons and the ion lattice (mainly due to electron-phonon interactions) are accounted for, the spectrum is more depressed depending on the magnetic field strength. Details of the emitted spectrum are found, however, to be strongly dependent of the assumed treatment of the transition from the external vacuum to the metallic surface. The implications of out results to RX J1856.5-3754 and other isolated neutron stars are discussed.

  5. A new Comptonization model for low-magnetized accreting neutron stars in low mass X-ray binaries

    E-Print Network [OSTI]

    R. Farinelli; L. Titarchuk; A. Paizis; F. Frontera

    2008-02-19

    We developed a new model for the X-ray spectral fitting \\xspec package which takes into account the effects of both thermal and dynamical (i.e. bulk) Comptonization. The model consists of two components: one is the direct blackbody-like emission due to seed photons which are not subjected to effective Compton scattering, while the other one is a convolution of the Green's function of the energy operator with a blackbody-like seed photon spectrum. When combined thermal and bulk effects are considered, the analytic form of the Green's function may be obtained as a solution of the diffusion Comptonization equation. Using data from the BeppoSAX, INTEGRAL and RXTE satellites, we test our model on the spectra of a sample of six persistently low magnetic field bright neutron star Low Mass X-ray Binaries, covering three different spectral states. Particular attention is given to the transient powerlaw-like hard X-ray (> 30 keV) tails that we interpret in the framework of the bulk motion Comptonization process. We show that the values of the best-fit delta-parameter, which represents the importance of bulk with respect to thermal Comptonization, can be physically meaningful and can at least qualitatively describe the physical conditions of the environment in the innermost part of the system. Moreover, we show that in fitting the thermal Comptonization spectra to the X-ray spectra of these systems, the best-fit parameters of our model are in excellent agreement with those of COMPTT, a broadly used and well established XSPEC model.

  6. The Vela pulsar with an active fallback disk

    SciTech Connect (OSTI)

    Özsükan, Gökçe; Ek?i, K. Yavuz [Faculty of Science and Letters, Department of Physics, ?stanbul Technical University, Maslak 34469, ?stanbul (Turkey); Hambaryan, Valeri; Neuhäuser, Ralph; Hohle, Markus M.; Ginski, Christian [Astrophysikalisches Institut und Universitäts-Sternwarte, Universität Jena, Schillergäßchen 2-3, 07745 Jena (Germany); Werner, Klaus, E-mail: eksi@itu.edu.tr [Institute for Astronomy and Astrophysics, Kepler Center for Astro and Particle Physics, Eberhard Karls University, Sand 1, D-72076 Tübingen (Germany)

    2014-11-20

    Fallback disks are expected to form around young neutron stars. The presence of these disks can be revealed by their blackbody spectrum in the infrared, optical, and UV bands. We present a re-reduction of the archival optical and infrared data of the Vela pulsar, together with the existing infrared and UV spectrum of Vela, and model their unpulsed components with the blackbody spectrum of a supernova debris disk. We invoke the quiescent disk solution of Sunyaev and Shakura for the description of the disk in the propeller stage and find the inner radius of the disk to be inside the light cylinder radius. We perform a high-resolution X-ray analysis with XMM-Newton and find a narrow absorption feature at 0.57 keV that can be interpreted as the K {sub ?} line of He-like oxygen (O VII). The strength of the line indicates an element over-abundance in our line of sight exceeding the amounts that would be expected from interstellar medium. The spectral feature may originate from the pulsar wind nebula and may be partly caused by the reprocessed X-ray radiation by the fallback disk. We discuss the lower-than-three braking index of Vela as partially due to the contribution of the propeller torques. Our results suggest that the pulsar mechanism can work simultaneously with the propeller processes and that the debris disks can survive the radiation pressure for at least ?10{sup 4} yr. As Vela is a relatively close object, and a prototypical pulsar, the presence of a disk, if confirmed, may indicate the ubiquity of debris disks around young neutron stars.

  7. Spectral differences between the radio-loud and radio-quiet low-hard states of GRS 1915+105: possible detection of synchrotron radiation in X-rays

    E-Print Network [OSTI]

    S. V. Vadawale; A. R. Rao; S. K. Chakrabarti

    2001-04-23

    The Galactic microquasar GRS 1915+105 exhibits several episodes of steady X-ray emission characterized by a hard power-law spectrum and intense Quasi Periodic Oscillations. It is known that there are two types of such low-hard states, one with steady radio emission and the other without any significant radio emission. We present the results of a detailed X-ray spectroscopic study of GRS 1915+105, using data from the Rossi X-ray Timing Explorer obtained during various episodes of the low-hard states of the source. We show that there are distinct X-ray spectral differences between the radio-quiet and radio-loud low-hard states of the source. The X-ray spectra of the radio-quiet low-hard state is best described by a model consisting ofa multicolor disk-blackbody and a Comptonized component, whereas the X-ray spectra of radio-loud low-hard state requires a model consisting of three components: a multicolor disk-blackbody, a Comptonized component and a power-law, for statistically and physically acceptable fits. We attempt to model the presence of this additional power-law component as due to synchrotronradiation which is responsible for the radio and infrared radiation from thesource. We show that a simple adiabatically expanding jet model for the synchrotron radiation can account for the observed X-ray flux for reasonable values of the magnetic field and the mass outflow rate. This is the first report of detection of the synchrotron radiation in the X-ray band for this source.

  8. DUST AROUND R CORONAE BOREALIS STARS. I. SPITZER/INFRARED SPECTROGRAPH OBSERVATIONS

    SciTech Connect (OSTI)

    Anibal Garcia-Hernandez, D. [Instituto de Astrofisica de Canarias, C/Via Lactea s/n, E-38200 La Laguna (Spain); Kameswara Rao, N. [Indian Institute of Astrophysics, Bangalore 560 034 (India); Lambert, David L., E-mail: agarcia@iac.es, E-mail: nkrao@iiap.res.in, E-mail: dll@astro.as.utexas.edu [W. J. McDonald Observatory, University of Texas at Austin, 1 University Station, C1400, Austin, TX 78712-0259 (United States)

    2011-09-20

    Spitzer/infrared spectrograph (IRS) spectra from 5 to 37 {mu}m for a complete sample of 31 R Coronae Borealis stars (RCBs) are presented. These spectra are combined with optical and near-infrared photometry of each RCB at maximum light to compile a spectral energy distribution (SED). The SEDs are fitted with blackbody flux distributions and estimates are made of the ratio of the infrared flux from circumstellar dust to the flux emitted by the star. Comparisons for 29 of the 31 stars are made with the Infrared Astronomical Satellite (IRAS) fluxes from three decades earlier: Spitzer and IRAS fluxes at 12 {mu}m and 25 {mu}m are essentially equal for all but a minority of the sample. For this minority, the IRAS to Spitzer flux ratio exceeds a factor of three. The outliers are suggested to be stars where formation of a dust cloud or dust puff is a rare event. A single puff ejected prior to the IRAS observations may have been reobserved by Spitzer as a cooler puff at a greater distance from the RCB. RCBs which experience more frequent optical declines have, in general, a circumstellar environment containing puffs subtending a larger solid angle at the star and a quasi-constant infrared flux. Yet, the estimated subtended solid angles and the blackbody temperatures of the dust show a systematic evolution to lower solid angles and cooler temperatures in the interval between IRAS and Spitzer. Dust emission by these RCBs and those in the LMC is similar in terms of total 24 {mu}m luminosity and [8.0]-[24.0] color index.

  9. Resolved imaging of the HR 8799 Debris disk with Herschel

    SciTech Connect (OSTI)

    Matthews, Brenda; Booth, Mark; Broekhoven-Fiene, Hannah; Marois, Christian [National Research Council of Canada Herzberg Astronomy and Astrophsyics, 5071 W. Saanich Road, Victoria, BC, V9E 2E7 (Canada); Kennedy, Grant; Wyatt, Mark [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Sibthorpe, Bruce [SRON Netherlands Institute for Space Research, P.O. Box 800, NL-9700 AV Groningen (Netherlands); Macintosh, Bruce [Lawrence Livermore National Labs, 7000 East Ave, Livermore, CA 94550 (United States)

    2014-01-01

    We present Herschel far-infrared and submillimeter maps of the debris disk associated with the HR 8799 planetary system. We resolve the outer disk emission at 70, 100, 160, and 250 ?m and detect the disk at 350 and 500 ?m. A smooth model explains the observed disk emission well. We observe no obvious clumps or asymmetries associated with the trapping of planetesimals that is a potential consequence of planetary migration in the system. We estimate that the disk eccentricity must be <0.1. As in previous work by Su et al., we find a disk with three components: a warm inner component and two outer components, a planetesimal belt extending from 100 to 310 AU, with some flexibility (±10 AU) on the inner edge, and the external halo that extends to ?2000 AU. We measure the disk inclination to be 26° ± 3° from face-on at a position angle of 64° E of N, establishing that the disk is coplanar with the star and planets. The spectral energy distribution of the disk is well fit by blackbody grains whose semi-major axes lie within the planetesimal belt, suggesting an absence of small grains. The wavelength at which the spectrum steepens from blackbody, 47 ± 30 ?m, however, is short compared with other A star debris disks, suggesting that there are atypically small grains likely populating the halo. The PACS longer wavelength data yield a lower disk color temperature than do MIPS data (24 and 70 ?m), implying two distinct halo dust-grain populations.

  10. Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report. October 1 - December 31, 2009.

    SciTech Connect (OSTI)

    D. L. Sisterson

    2010-01-12

    Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent approximately daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998. The U.S. Department of Energy (DOE) requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1 - (ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for the first quarter of FY 2010 for the North Slope Alaska (NSA) locale is 1,987.20 hours (0.90 x 2,208); for the Southern Great Plains (SGP) site is 2,097.60 hours (0.95 x 2,208); and for the Tropical Western Pacific (TWP) locale is 1,876.8 hours (0.85 x 2,208). The ARM Mobile Facility (AMF) deployment in Graciosa Island, the Azores, Portugal, continues; its OPSMAX time this quarter is 2,097.60 hours (0.95 x 2,208). The differences in OPSMAX performance reflect the complexity of local logistics and the frequency of extreme weather events. It is impractical to measure OPSMAX for each instrument or data stream. Data availability reported here refers to the average of the individual, continuous data streams that have been received by the Archive. Data not at the Archive are the result of downtime (scheduled or unplanned) of the individual instruments. Therefore, data availability is directly related to individual instrument uptime. Thus, the average percentage of data in the Archive represents the average percentage of the time (24 hours per day, 92 days for this quarter) the instruments were operating this quarter. The Site Access Request System is a web-based database used to track visitors to the fixed and mobile sites, all of which have facilities that can be visited. The NSA locale has the Barrow and Atqasuk sites. The SGP locale has historically had a central facility, 23 extended facilities, 4 boundary facilities, and 3 intermediate facilities. Beginning this quarter, the SGP began a transition to a smaller footprint (150 km x 150 km) by rearranging the original and new instrumentation made available through the American Recovery and Reinvestment Act (ARRA). The central facility and 4 extended facilities will remain, but there will be up to 16 surface new characterization facilities, 4 radar facilities, and 3 profiler facilities sited in the smaller domain. This new configuration will provide observations at scales more appropriate to current and future climate models. The TWP locale has the Manus, Nauru, and Darwin sites. These sites will also have expanded measurement capabilities with the addition of new instrumentation made available through ARRA funds. It is anticipated that the new instrumentation at all the fixed sites will be in place within the next 12 months. The AMF continues its 20-month deployment in Graciosa Island, Azores, Portugal, that started May 1, 2009. The AMF will also have additional observational capabilities within the next 12 months. Users can participate in field experiments at the sites and mobile facility, or they can participate remotely. Therefore, a variety of mechanisms are provided to users to access site information. Users who have immediate (real-time) needs for data access can request a research account on the local site data systems. This access is particularly useful to users for quick decisions in executing time-dependent activities associated with field campaigns at the fixed sites and mobile facility locations. T

  11. TIDAL DISRUPTION FLARES: THE ACCRETION DISK PHASE

    SciTech Connect (OSTI)

    Montesinos Armijo, Matias; De Freitas Pacheco, Jose A. [Observatoire de la Cote d'Azur, Laboratoire Cassiopee, Universite de Nice Sophia-Antipolis Bd de l'Observatoire, BP 4229, 06304 Nice Cedex 4 (France)

    2011-08-01

    The evolution of an accretion disk, formed as a consequence of the disruption of a star by a black hole, is followed by solving numerically hydrodynamic equations. The present investigation aims to study the dependence of resulting light curves on dynamical and physical properties of such a transient disk during its existence. One of the main results derived from our simulations is that blackbody fits of X-ray data tend to overestimate the true mean disk temperature. In fact, the temperature derived from blackbody fits should be identified with the color X-ray temperature rather than the average value derived from the true temperature distribution along the disk. The time interval between the beginning of the circularization of the bound debris and the beginning of the accretion process by the black hole is determined by the viscous (or accretion) timescale, which also fixes the rising part of the resulting light curve. The luminosity peak coincides with the beginning of matter accretion by the black hole and the late evolution of the light curve depends on the evolution of the debris fallback rate. Peak bolometric luminosities are in the range 10{sup 45}-10{sup 46} erg s{sup -1}, whereas peak luminosities in soft X-rays (0.2-2.0 keV) are typically one order of magnitude lower. The typical timescale derived from our preferred models for the flare luminosity to decay by two orders of magnitude is about 3-4 yr. Predicted soft X-ray light curves reproduce quite well data on galaxies in which a variable X-ray emission possibly related to a tidal event was detected. In the cases of NGC 3599 and IC 3599, data are reproduced well by models defined by a black hole with mass {approx}10{sup 7} M{sub sun} and a disrupted star of about 1 solar mass. The X-ray variation observed in XMMSL1 is consistent with a model defined by a black hole with mass {approx}3 x 10{sup 6} M{sub sun} and a disrupted star of 1 solar mass, while that observed in the galaxy situated in the cluster A1689 is consistent with a model including a black hole of {approx}10{sup 7} M{sub sun} and a disrupted star of {approx}0.5 M{sub sun}.

  12. Integrated assessment of global warming

    SciTech Connect (OSTI)

    Ott, K.O.

    1996-12-31

    The anomalies of sea surface temperatures, which show a warming trend since the 1850s through the decade 1960/70 of {Delta}SST {approximately} 0.3 C, are complemented by changes of the ground surface temperature ({Delta}GST). The global surface temperature change, based on these data, allows an integrated assessment of the associated increase in black-body irradiance and a comparison with the enhanced greenhouse-gas back-scattering. Information on the GST history is obtained from unfolding analyses of underground temperature distributions measured in 90 boreholes in Alaskan permafrost and Canadian bedrock. These analyses show GST increases ({Delta}GST) since the 19th century through 1960/70 of 3 C on average, with standard deviations of +1.8 C and {minus}0.9 C on the high and low end respectively. The onset of the warming trend, which is uncertain in the GST data, is timed more accurately by detailed length records of large valley glaciers in the US and the Alps. Evaluation of the heat capacities and heat transfer indicates that the temperature response to an increase in radiative forcing must be much larger on land than on the sea. Conversely, the observed large ratio of {Delta}GST and {Delta}SST can only be explained by increased radiative forcing. From 1960/70 through the warmest decade on record, 1980/90, global {Delta}SST and {Delta}SAT have further increased to 0.6 C and 0.8 C respectively, But, the most recent GST data are not accurate enough to extend the comparison through 1990. Calculation of the increase of radiative forcing from back-scattering of greenhouse gases for 1850 to 1970 yields 1.3 W/cm{sup 2}. The increase in black-body irradiance from 3.6 C warming on land and 0.3 C on sea provides the required balance. The warming on land of 3.6 C is larger than the average value of 3.0 C, but well within the observed range.

  13. Point X-ray sources in the SNR G 315.4-2.30 (MSH 14-63, RCW 86)

    E-Print Network [OSTI]

    V. V. Gvaramadze; A. A. Vikhlinin

    2002-12-25

    We report the results of a search for a point X-ray source (stellar remnant) in the southwest protrusion of the supernova remnant G 315.4-2.30 (MSH 14-63, RCW 86) using the archival data of the Chandra X-ray Observatory. The search was motivated by a hypothesis that G 315.4-2.30 is the result of an off-centered cavity supernova explosion of a moving massive star, which ended its evolution just near the edge of the main-sequence wind-driven bubble. This hypothesis implies that the southwest protrusion in G 315.4-2.30 is the remainder of a pre-existing bow shock-like structure created by the interaction of the supernova progenitor's wind with the interstellar medium and that the actual location of the supernova blast center is near the center of this hemispherical structure. We have discovered two point X-ray sources in the "proper" place. One of the sources has an optical counterpart with the photographic magnitude $13.38\\pm0.40$, while the spectrum of the source can be fitted with an optically thin plasma model. We interpret this source as a foreground active star of late spectral type. The second source has no optical counterpart to a limiting magnitude $\\sim 21$. The spectrum of this source can be fitted almost equally well with several simple models (power law: photon index $=1.87$; two-temperature blackbody: $kT_1 =0.11$ keV, $R_1 =2.34 $ km and $kT_2 =0.71$ keV, $R_2 =0.06$ km; blackbody plus power law: $kT =0.07$ keV, photon index $=2.3$). We interpret this source as a candidate stellar remnant (neutron star), while the photon index and non-thermal luminosity of the source (almost the same as those of the Vela pulsar and the recently discovered pulsar PSR J 0205+6449 in the supernova remnant 3C 58) suggest that it can be a young "ordinary" pulsar.

  14. Towards the development of high temperature comparison artifacts for radiation thermometry

    SciTech Connect (OSTI)

    Teixeira, R. N. [Inmetro, Duque de Caxias, RJ (Brazil)] [Inmetro, Duque de Caxias, RJ (Brazil); Machin, G. [NPL, Teddington (United Kingdom)] [NPL, Teddington (United Kingdom); Orlando, A. [PUC-Rio, Rio de Janeiro, RJ (Brazil)] [PUC-Rio, Rio de Janeiro, RJ (Brazil)

    2013-09-11

    This paper describes the methodology and first results of the development of high temperature fixed point artifacts of unknown temperature suitable for scale comparison purposes. This study is being undertaken at the Thermal Metrology Division of Inmetro, Brazil, as part of PhD studies. In this initial phase of the study two identical cobalt carbon eutectic cells were constructed and one doped with a known amount of copper. This was an attempt to achieve a controlled change in the transition temperature of the alloy during melting. Copper was chosen due to the relatively simple phase diagram it forms with carbon and cobalt. The cobalt, in powder form, was supplied by Alfa Aesar at 99.998 % purity, and was mixed with carbon powder (1,9 % by weight) of 99.9999 % purity. Complete filling of the crucible took 6 steps and was performed in a vertical furnace with graphite heating elements, in an inert gas atmosphere. The temperature measurements were performed using a KE LP3 radiation thermometer, which was previously evaluated for spectral responsivity, linearity and size-of-source effect (SSE). During these measurements, the thermometer stability was periodically checked using a silver fixed point blackbody maintained in a three zone furnace. The main purpose of the first part of this study is to dope a series of Co-C blackbody with differing amounts of copper, in order to alter their temperatures whilst still retaining good melting plateau performance. The long-term stability of the adjusted transition temperatures will also be investigated. Other dopants will be studied as the research progresses, and thermo chemical modeling will be performed in an attempt to understand the change in temperature with dopant concentration and so help select suitable dopants in the future. The overall objective is to construct comparison artifacts that have good performance, in terms of plateau shape and long-term temperature stability, but with unknown temperatures. These can then be used as comparison artifacts with no participant, except the pilot, knowing the temperature a priori.

  15. BER Science Network Requirements Workshop -- July 26-27,2007

    SciTech Connect (OSTI)

    Tierney, Brian L.; Dart, Eli

    2008-02-01

    The Energy Sciences Network (ESnet) is the primary provider of network connectivity for the US Department of Energy Office of Science, the single largest supporter of basic research in the physical sciences in the United States of America. In support of the Office of Science programs, ESnet regularly updates and refreshes its understanding of the networking requirements of the instruments, facilities, scientists, and science programs that it serves. This focus has helped ESnet to be a highly successful enabler of scientific discovery for over 20 years. In July 2007, ESnet and the Biological and Environmental Research (BER) Program Office of the DOE Office of Science organized a workshop to characterize the networking requirements of the science programs funded by the BER Program Office. These included several large programs and facilities, including Atmospheric Radiation Measurement (ARM) Program and the ARM Climate Research Facility (ACRF), Bioinformatics and Life Sciences Programs, Climate Sciences Programs, the Environmental Molecular Sciences Laboratory at PNNL, the Joint Genome Institute (JGI). National Center for Atmospheric Research (NCAR) also participated in the workshop and contributed a section to this report due to the fact that a large distributed data repository for climate data will be established at NERSC, ORNL and NCAR, and this will have an effect on ESnet. Workshop participants were asked to codify their requirements in a 'case study' format, which summarizes the instruments and facilities necessary for the science and the process by which the science is done, with emphasis on the network services needed and the way in which the network is used. Participants were asked to consider three time scales in their case studies--the near term (immediately and up to 12 months in the future), the medium term (3-5 years in the future), and the long term (greater than 5 years in the future). In addition to achieving its goal of collecting and characterizing the network requirements of the science endeavors funded by the BER Program Office, the workshop emphasized some additional points. These included the need for a future ESnet presence in the Denver area, a desire for ESnet to continue support of collaboration services, and the need for ESnet to support dedicated bandwidth or 'virtual circuit' services. In addition, it is clear that the BER facilities are going to experience significant growth in data production over the next 5 years. The reasons for this vary (model resolution and supercomputer allocations for climate, detector upgrades for EMSL and ARM, sequencing hardware upgrades for JGI), but all indicators point to significant growth in data volumes over the near to medium term. This growth in data volume, combined with the ever-expanding scope of scientific collaboration, will continue to demand ever-increasing bandwidth, reliability and service richness from the networks that support DOE science.

  16. Peculiar Near-Nucleus Outgassing of Comet 17P/Holmes During Its 2007 Outburst

    E-Print Network [OSTI]

    Qi, Chunhua; Jewitt, David; Gurwell, Mark A; Wilner, David J

    2014-01-01

    We present high angular resolution Submillimeter Array observations ofthe outbursting Jupiter family comet 17P/Holmes on 2007 October 26-29, achieving a spatial resolution of 2.5", or ~3000 km at the comet distance. The observations resulted in detections of the rotational lines CO 3-2, HCN 4-3, H$^{13}$CN 4-3, CS 7-6, H$_2$CO 3$_{1,2}$-2$_{1,1}$, H$_2$S 2$_{2,0}$-2$_{1,1}$, and multiple CH$_3$OH lines, along with the associated dust continuum at 221 and 349 GHz. The continuum has a spectral index of 2.7$\\pm$0.3, slightly steeper than blackbody emission from large dust particles. From the imaging data, we identify two components in the molecular emission. One component is characterized by a relatively broad line width (~1 km s$^{-1}$ FWHM) exhibiting a symmetric outgassing pattern with respect to the nucleus position. The second component has a narrower line width (<0.5 km s$^{-1}$ FWHM) with the line center red-shifted by 0.1-0.2 km s$^{-1}$ (cometocentric frame), and shows a velocity shift across the nuc...

  17. Constraining the parameters of the pulsar wind nebula DA 495 and its pulsar with Chandra and XMM-Newton

    E-Print Network [OSTI]

    Karpova, A; Danilenko, A; Shibanov, Yu

    2015-01-01

    We present spectral and timing analyses of the X-ray emission from the pulsar wind nebula DA 495 and its central object, J1952.2+2925, suggested to be the pulsar, using archival Chandra and XMM-Newton data. J1952.2+2925 has a pure thermal spectrum which is equally well fitted either by the blackbody model with a temperature of $\\approx 215$ eV and an emitting area radius of $\\approx 0.6$ km or by magnetized neutron star atmosphere models with temperatures of 80-90 eV. In the latter case the thermal emission can come from the entire neutron star surface which temperature is consistent with standard neutron star cooling scenarios. We place also an upper limit on the J1952.2+2925 nonthermal flux. The derived spectral parameters are generally compatible with published ones based only on the Chandra data, but they are much more accurate due to the inclusion of XMM-Newton data. No pulsations were found and we placed an upper limit for the J1952.2+2925 pulsed emission fraction of 40 per cent. Utilizing the interstel...

  18. Extreme temperature robust optical sensor designs and fault-tolerant signal processing

    DOE Patents [OSTI]

    Riza, Nabeel Agha (Oviedo, FL); Perez, Frank (Tujunga, CA)

    2012-01-17

    Silicon Carbide (SiC) probe designs for extreme temperature and pressure sensing uses a single crystal SiC optical chip encased in a sintered SiC material probe. The SiC chip may be protected for high temperature only use or exposed for both temperature and pressure sensing. Hybrid signal processing techniques allow fault-tolerant extreme temperature sensing. Wavelength peak-to-peak (or null-to-null) collective spectrum spread measurement to detect wavelength peak/null shift measurement forms a coarse-fine temperature measurement using broadband spectrum monitoring. The SiC probe frontend acts as a stable emissivity Black-body radiator and monitoring the shift in radiation spectrum enables a pyrometer. This application combines all-SiC pyrometry with thick SiC etalon laser interferometry within a free-spectral range to form a coarse-fine temperature measurement sensor. RF notch filtering techniques improve the sensitivity of the temperature measurement where fine spectral shift or spectrum measurements are needed to deduce temperature.

  19. A 2.4 - 12 microns spectrophotometric study with ISO of Cygnus X-3 in quiescence

    E-Print Network [OSTI]

    Lydie Koch-Miramond; P'eter 'Abrah'am; Ya"el Fuchs; Jean-Marc Bonnet-Bidaud; Arnaud Claret

    2002-07-22

    We present mid-infrared spectrophotometric results obtained with the ISO on the peculiar X-ray binary Cygnus X-3 in quiescence, at orbital phases 0.83 to 1.04. The 2.4-12 microns continuum radiation observed with ISOPHOT-S can be explained by thermal free-free emission in an expanding wind with, above 6.5 microns, a possible additional black-body component with temperature T ~ 250 K and radius R ~ 5000 solar radii at 10 kpc, likely due to thermal emission by circumstellar dust. The observed brightness and continuum spectrum closely match that of the Wolf-Rayet star WR 147, a WN8+B0.5 binary system, when rescaled at the same 10 kpc distance as Cygnus X-3. A rough mass loss estimate assuming a WN wind gives ~ 1.2 10^{-4} M(sun)/yr. A line at ~ 4.3 microns with a more than 4.3 sigma detection level, and with a dereddened flux of 126 mJy, is interpreted as the expected He I 3p-3s line at 4.295 microns, a prominent line in the WR 147 spectrum. These results are consistent with a Wolf-Rayet-like companion to the compact object in Cygnus X-3 of WN8 type, a later type than suggested by earlier works.

  20. The Complete Census of 70-um-Bright Debris Disks within the FEPS (Formation and Evolution of Planetary Systems) Spitzer Legacy Survey of Sun-like Stars

    E-Print Network [OSTI]

    Lynne A. Hillenbrand; John M. Carpenter; Jinyoung Serena Kim; Michael R. Meyer; Dana E. Backman; Amaya Moro-Martin; David J. Hollenbach; Dean C. Hines; Ilaria Pascucci; Jeroen Bouwman

    2007-12-30

    (abbreviated) We report detection with the Spitzer Space Telescope of cool dust surrounding solar type stars. The observations were performed as part of the Legacy Science Program, ``Formation and Evolution of Planetary Systems'' (FEPS). From the overall FEPS sample (Meyer et al. 2006) of 328 stars having ages ~0.003-3 Gyr we have selected sources with 70 um flux densities indicating excess in their spectral energy distributions above expected photospheric emission........ .....The rising spectral energy distributions towards - and perhaps beyond - 70 um imply dust temperatures T_dust temperature, location, fractional luminosity, and mass of the dust from fitted single temperature blackbody models. For >1/3 of the debris sources we find that multiple temperature components are suggested, implying a spatial distribution of dust extending over many tens of AU. Because the disks are dominated by collisional processes, the parent body (planetesimal) belts may be extended as well. Preliminary assessment of the statistics of cold debris around sun-like stars shows that ~10% of FEPS targets with masses between 0.6 and 1.8 Msun and ages between 30 Myr and 3 Gyr exhibit 70 um emission in excess of the expected photospheric flux density. We find that fractional excess amplitudes appear higher for younger stars and that there may be a trend in 70 um excess frequency with stellar mass.

  1. A comparison of absolute calibrations of a radiation thermometer based on a monochromator and a tunable source

    SciTech Connect (OSTI)

    Keawprasert, T.; Anhalt, K.; Taubert, D. R.; Sperling, A.; Schuster, M.; Nevas, S.

    2013-09-11

    An LP3 radiation thermometer was absolutely calibrated at a newly developed monochromator-based set-up and the TUneable Lasers in Photometry (TULIP) facility of PTB in the wavelength range from 400 nm to 1100 nm. At both facilities, the spectral radiation of the respective sources irradiates an integrating sphere, thus generating uniform radiance across its precision aperture. The spectral irradiance of the integrating sphere is determined via an effective area of a precision aperture and a Si trap detector, traceable to the primary cryogenic radiometer of PTB. Due to the limited output power from the monochromator, the absolute calibration was performed with the measurement uncertainty of 0.17 % (k= 1), while the respective uncertainty at the TULIP facility is 0.14 %. Calibration results obtained by the two facilities were compared in terms of spectral radiance responsivity, effective wavelength and integral responsivity. It was found that the measurement results in integral responsivity at the both facilities are in agreement within the expanded uncertainty (k= 2). To verify the calibration accuracy, the absolutely calibrated radiation thermometer was used to measure the thermodynamic freezing temperatures of the PTB gold fixed-point blackbody.

  2. Cooling of the crust in the neutron star low-mass X-ray binary MXB 1659-29

    E-Print Network [OSTI]

    Edward M. Cackett; Rudy Wijnands; Jon M. Miller; Edward F. Brown; Nathalie Degenaar

    2008-09-24

    In quasi-persistent neutron star transients, long outbursts cause the neutron star crust to be heated out of thermal equilibrium with the rest of the star. During quiescence, the crust then cools back down. Such crustal cooling has been observed in two quasi-persistent sources: KS 1731-260 and MXB 1659-29. Here we present an additional Chandra observation of MXB 1659-29 in quiescence, which extends the baseline of monitoring to 6.6 yr after the end of the outburst. This new observation strongly suggests that the crust has thermally relaxed, with the temperature remaining consistent over 1000 days. Fitting the temperature cooling curve with an exponential plus constant model we determine an e-folding timescale of 465 +/- 25 days, with the crust cooling to a constant surface temperature of kT = 54 +/- 2 eV (assuming D=10 kpc). From this, we infer a core temperature in the range 3.5E7-8.3E7 K (assuming D=10 kpc), with the uncertainty due to the surface composition. Importantly, we tested two neutron star atmosphere models as well as a blackbody model, and found that the thermal relaxation time of the crust is independent of the chosen model and the assumed distance.

  3. SOFIA Infrared Spectrophotometry of Comet C/2012 K1 (Pan-STARRS)

    E-Print Network [OSTI]

    Woodward, Charles E; Harker, David E; Ryan, Erin L; Wooden, Diane H; Sitko, Michael L; Russell, Ray W; Reach, William T; de Pater, Imke; Kolokolova, Ludmilla; Gehrz, Robert D

    2015-01-01

    We present pre-perihelion infrared 8 to 31 micron spectrophotometric and imaging observations of comet C/2012 K1 (Pan-STARRS), a dynamically new Oort Cloud comet, conducted with NASA's Stratospheric Observatory for Infrared Astronomy (SOFIA) facility (+FORCAST) in 2014 June. As a "new" comet (first inner solar system passage), the coma grain population may be extremely pristine, unencumbered by a rime and insufficiently irradiated by the Sun to carbonize its surface organics. The comet exhibited a weak 10 micron silicate feature ~1.18 +/- 0.03 above the underlying best-fit 215.32 +/- 0.95 K continuum blackbody. Thermal modeling of the observed spectral energy distribution indicates that the coma grains are fractally solid with a porosity factor D = 3 and the peak in the grain size distribution, a_peak = 0.6 micron, large. The sub-micron coma grains are dominated by amorphous carbon, with a silicate-to-carbon ratio of 0.80 (+0.25) (- 0.20). The silicate crystalline mass fraction is 0.20 (+0.30) (-0.10), simila...

  4. Observational Properties of Type Ib/c Supernova Progenitors in Binary Systems

    E-Print Network [OSTI]

    Kim, Hyun-Jeong; Koo, Bon-Chul

    2015-01-01

    In several recent observational studies on Type Ib/c supernovae (SNe Ib/c), the inferred ejecta masses have a peak value of 2.0 -- 4.0 $M_\\odot$, in favor of the binary scenario for their progenitors rather than the Wolf-Rayet star scenario. To investigate the observational properties of relatively low-mass helium stars in binary systems as SN Ib/c progenitors, we constructed atmospheric models with the non-LTE radiative transfer code CMFGEN, using binary star evolution models. We find that these helium stars can be characterized by relatively narrow helium emission lines if the mass-loss rate during the final evolutionary phase is significantly enhanced as implied by many SN Ib/c observations. The optical brightness of helium star progenitors can be meaningfully enhanced with a strong wind for $M \\gtrsim 4.4 M_\\odot$, but hardly affected or slightly weakened for relatively low-mass of $\\sim 3.0 M_\\odot$, compared to the simple estimate using blackbody approximation. We further confirm the previous suggestion...

  5. Revealing a hard X-ray spectral component reverberating within one light hour of the central Supermassive Black Hole in Ark 564

    E-Print Network [OSTI]

    Giustini, M; Reeves, J N; Miller, L; Legg, E; Kraemer, S B; George, I M

    2015-01-01

    Ark 564 (z=0.0247) is an X-ray bright NLS1. By using advanced X-ray timing techniques, Legg et al. (2012) discovered an excess of "delayed" emission in the hard X-ray band (4-7.5 keV) following about 1000 seconds after "flaring" light in the soft X-ray band (0.4-1 keV). We report on the X-ray spectral analysis of eight XMM-Newton and one Suzaku observation of Ark 564. High-resolution spectroscopy was performed with the RGS in the soft X-ray band, while broad-band spectroscopy was performed with the EPIC-pn and XIS/PIN instruments. We analysed time-averaged, flux-selected, and time-resolved spectra. Despite the large variability in flux, the broad band spectral shape of Ark 564 is not dramatically varying and can be reproduced either by a superposition of a power law and a blackbody emission, or by a Comptonized power law emission model. High resolution spectroscopy revealed the presence of ionised gas along the line of sight at the systemic redshift of the source, with a low column density and a range of ioni...

  6. The central stars of the planetary nebulae NGC 7027 and NGC 6543

    E-Print Network [OSTI]

    D. A. Beintema; P. A. M. van Hoof; F. Lahuis; S. R. Pottasch; L. B. F. M. Waters; Th. de Graauw; D. R. Boxhoorn; H. Feuchtgruber; P. W. Morris

    1999-06-09

    Infrared spectra of NGC 7027 and NGC 6543 ranging from 2.4 to 45 micron were obtained with the Short Wavelength Spectrometer on board the Infrared Space Observatory. A first analysis of these spectra, with the aid of photo-ionization models, is presented. We report the first detection of the Ar VI 4.53 micron and Ne VI 7.65 micron lines in the spectrum of NGC 7027. When compared with older observations it is clear that the Ar VI line and possibly also other lines have increased in strength since 1981. We argue that a likely explanation for this variability is a change in the spectral energy distribution of the central star, possibly an increase in effective temperature. However, this result needs to be confirmed by further observations. We also report a non-detection of the O IV 25.9 micron line and the first detection of the Na III 7.32 micron line in the spectrum of NGC 6543. The non-detection is not expected based on a blackbody approximation for the spectrum of the central star. The ionization threshold for O(3+) is just beyond the He II limit, and the absence of this line shows that the stellar flux drops at least by a factor 350 at the He II limit. Modeling the O IV line may prove to be a valuable test for atmosphere models.

  7. Non-LTE modeling of supernova-fallback disks

    E-Print Network [OSTI]

    K. Werner; T. Nagel; T. Rauch

    2006-08-24

    We present a first detailed spectrum synthesis calculation of a supernova-fallback disk composed of iron. We assume a geometrically thin disk with a radial structure described by the classical alpha-disk model. The disk is represented by concentric rings radiating as plane-parallel slabs. The vertical structure and emission spectrum of each ring is computed in a fully self-consistent manner by solving the structure equations simultaneously with the radiation transfer equations under non-LTE conditions. We describe the properties of a specific disk model and discuss various effects on the emergent UV/optical spectrum. We find that strong iron-line blanketing causes broad absorption features over the whole spectral range. Limb darkening changes the spectral distribution up to a factor of four depending on the inclination angle. Consequently, such differences also occur between a blackbody spectrum and our model. The overall spectral shape is independent of the exact chemical composition as long as iron is the dominant species. A pure iron composition cannot be distinguished from silicon-burning ash. Non-LTE effects are small and restricted to few spectral features.

  8. Time-dependent modeling of radiative processes in hot magnetized plasmas

    E-Print Network [OSTI]

    Indrek Vurm; Juri Poutanen

    2009-03-03

    Numerical simulations of radiative processes in magnetized compact sources such as hot accretion disks around black holes, relativistic jets in active galaxies and gamma-ray bursts are complicated because the particle and photon distributions span many orders of magnitude in energy, they also strongly depend on each other, the radiative processes behave significantly differently depending on the energy regime, and finally due to the enormous difference in the time-scales of the processes. We have developed a novel computer code for the time-dependent simulations that overcomes these problems. The processes taken into account are Compton scattering, electron-positron pair production and annihilation, Coulomb scattering as well as synchrotron emission and absorption. No approximation has been made on the corresponding rates. For the first time, we solve coupled integro-differential kinetic equations for photons and electrons/positrons without any limitations on the photon and lepton energies. A numerical scheme is proposed to guarantee energy conservation when dealing with synchrotron processes in electron and photon equations. We apply the code to model non-thermal pair cascades in the blackbody radiation field, to study the synchrotron self-absorption as particle thermalization mechanism, and to simulate time evolution of stochastically heated pairs and corresponding synchrotron self-Compton photon spectra which might be responsible for the prompt emission of gamma-ray bursts. Good agreement with previous works is found in the parameter regimes where comparison is feasible, with the differences attributable to our improved treatment of the microphysics.

  9. GROUND-BASED DETECTIONS OF THERMAL EMISSION FROM THE DENSE HOT JUPITER WASP-43b IN THE H AND K{sub s} BANDS

    SciTech Connect (OSTI)

    Wang, W.; Zhao, G.; Van Boekel, R.; Henning, Th.; Madhusudhan, N.; Chen, G.

    2013-06-10

    We report new detections of thermal emission from the transiting hot Jupiter WASP-43b in the H and K{sub s} bands as observed at secondary eclipses. The observations were made with the WIRCam instrument on the Canada-France-Hawaii Telescope. We obtained a secondary eclipse depth of 0.103{sub -0.017}{sup +0.017}%$ and 0.194{sub -0.029}{sup +0.029} in the H and K{sub s} bands, respectively. The K{sub s}-band depth is consistent with the previous measurement in the narrow band centered at 2.09 {mu}m by Gillon et al. Our eclipse depths in both bands are consistent with a blackbody spectrum with a temperature of {approx}1850 K, slightly higher than the dayside equilibrium temperature without day-night energy redistribution. Based on theoretical models of the dayside atmosphere of WASP-43b, our data constrain the day-night energy redistribution in the planet to be {approx}< 15%-25%, depending on the metal content in the atmosphere. Combined with energy balance arguments, our data suggest that a strong temperature inversion is unlikely in the dayside atmosphere of WASP-43b. However, a weak inversion cannot be strictly ruled out at the current time. Future observations are required to place detailed constraints on the chemical composition of the atmosphere.

  10. Thermal and Bulk Comptonization in Accretion-Powered X-Ray Pulsars

    E-Print Network [OSTI]

    Peter A. Becker; Michael T. Wolff

    2006-09-01

    We develop a new theoretical model for the spectral formation process in accretion-powered X-ray pulsars based on a detailed treatment of the bulk and thermal Comptonization occurring in the accreting, shocked gas. A rigorous eigenfunction expansion method is employed to obtain the analytical solution for the Green's function describing the scattering of radiation injected into the column from a monochromatic source located at an arbitrary height above the stellar surface. The emergent spectrum is calculated by convolving the Green's function with source terms corresponding to bremsstrahlung, cyclotron, and blackbody emission. The energization of the photons in the shock, combined with cyclotron absorption, naturally produces an X-ray spectrum with a relatively flat continuum shape and a high-energy quasi-exponential cutoff. We demonstrate that the new theory successfully reproduces the phase-averaged spectra of the bright pulsars Her X-1, LMC X-4, and Cen X-3. In these luminous sources, it is shown that the emergent spectra are dominated by Comptonized bremsstrahlung emission.

  11. Fe K Line Profile in Low-redshift Quasars: Average Shape and Eddington Ratio Dependence

    E-Print Network [OSTI]

    Hirohiko Inoue; Yuichi Terashima; Luis C. Ho

    2007-03-14

    We analyze X-ray spectra of 43 Palomar-Green quasars observed with {\\it XMM-Newton} in order to investigate their mean Fe K line profile and its dependence on physical properties. The continuum spectra of 39 objects are well reproduced by a model consisting of a power law and a blackbody modified by Galactic absorption. The spectra of the remaining four objects require an additional power-law component absorbed with a column density of $\\sim 10^{23} {\\rm cm}^{-2}$. We fit the entire sample simultaneously to derive average Fe line parameters by assuming a common Fe line shape. The Fe line is relatively narrow ($\\sigma=0.36$ keV), with a center energy of 6.48 keV and a mean equivalent width (EW) of 248 eV. By combining black hole masses estimated from the virial method and bolometric luminosities derived from full spectral energy distributions, we examine the dependence of the Fe K line profile on Eddington ratio. As the Eddington ratio increases, the line becomes systematically stronger (EW = 130 to 280 eV), broader ($\\sigma=0.1$ to 0.7 keV), and peaks at higher energies (6.4 to 6.8 keV). This result suggests that the accretion rate onto the black hole directly influences the geometrical structure and ionization state of the accretion disk.

  12. Comptonization and the Spectra of Accretion-Powered X-Ray Pulsars

    E-Print Network [OSTI]

    Michael T. Wolff; Peter A. Becker; Kenneth D. Wolfram

    2007-04-17

    Accretion-powered X-ray pulsars are among the most luminous X-ray sources in the Galaxy. However, despite decades of theoretical and observational work since their discovery, no satisfactory model for the formation of the observed X-ray spectra has emerged. In this paper, we report on a self-consistent calculation of the spectrum emerging from a pulsar accretion column that includes an explicit treatment of the bulk and thermal Comptonization occurring in the radiation-dominated shocks that form in the accretion flows. Using a rigorous eigenfunction expansion method, we obtain a closed-form expression for the Green's function describing the upscattering of monochromatic radiation injected into the column. The Green's function is convolved with bremsstrahlung, cyclotron, and blackbody source terms to calculate the emergent photon spectrum. We show that energization of photons in the shock naturally produces an X-ray spectrum with a relatively flat continuum and a high-energy exponential cutoff. Finally, we demonstrate that our model yields good agreement with the spectra of the bright pulsar Her X-1 and the low luminosity pulsar X Per.

  13. Six Months of Multi-Wavelength Follow-up of the Tidal Disruption Candidate ASASSN-14li and Implied TDE Rates from ASAS-SN

    E-Print Network [OSTI]

    Holoien, T W -S; Prieto, J L; Stanek, K Z; Dong, Subo; Shappee, B J; Grupe, D; Brown, J S; Basu, U; Beacom, J F; Bersier, D; Brimacombe, J; Danilet, A B; Falco, E; Guo, Z; Jose, J; Herczeg, G J; Long, F; Pojmanski, G; Simonian, G V; Szczygiel, D M; Thompson, T A; Thorstensen, J R; Wozniak, P R

    2015-01-01

    We present ground-based and Swift photometric and spectroscopic observations of the candidate tidal disruption event (TDE) ASASSN-14li, found at the center of PGC 043234 ($d\\simeq90$~Mpc) by the All-Sky Automated Survey for SuperNovae (ASAS-SN). The source had a peak bolometric luminosity of $L\\simeq10^{44}$ ergs s$^{-1}$ and a total integrated energy of $E\\simeq7\\times10^{50}$ ergs radiated over the $\\sim6$ months of observations presented. The UV/optical emission of the source is well-fit by a blackbody with roughly constant temperature of $T\\sim35,000$ K, while the luminosity declines by roughly a factor of 16 over this time. The optical/UV luminosity decline is broadly consistent with an exponential decline, $L\\propto e^{-t/t_0}$, with $t_0\\simeq60$ days. ASASSN-14li also exhibits soft X-ray emission comparable in luminosity to the optical and UV emission but declining at a slower rate, and the X-ray emission now dominates. Spectra of the source show broad Balmer and helium lines in emission as well as st...

  14. CHIANTI - an Atomic Database for Emission Lines. Paper VI: Proton Rates and Other Improvements

    E-Print Network [OSTI]

    P. R. Young; G. Del Zanna; E. Landi; K. P. Dere; H. E. Mason; M. Landini

    2002-09-24

    The CHIANTI atomic database contains atomic energy levels, wavelengths, radiative transition probabilities and electron excitation data for a large number of ions of astrophysical interest. Version 4 has been released, and proton excitation data is now included, principally for ground configuration levels that are close in energy. The fitting procedure for excitation data, both electrons and protons, has been extended to allow 9 point spline fits in addition to the previous 5 point spline fits. This allows higher quality fits to data from close-coupling calculations where resonances can lead to significant structure in the Maxwellian-averaged collision strengths. The effects of photoexcitation and stimulated emission by a blackbody radiation field in a spherical geometry on the level balance equations of the CHIANTI ions can now be studied following modifications to the CHIANTI software. With the addition of H I, He I and N I, the first neutral species have been added to CHIANTI. Many updates to existing ion data-sets are described, while several new ions have been added to the database, including Ar IV, Fe VI and Ni XXI. The two-photon continuum is now included in the spectral synthesis routines, and a new code for calculating the relativistic free-free continuum has been added. The treatment of the free-bound continuum has also been updated.

  15. A Complete Relativistic Ionized Accretion Disc in Cygnus X-1

    E-Print Network [OSTI]

    A. J. Young; A. C. Fabian; R. R. Ross; Y. Tanaka

    2001-03-14

    The galactic black hole candidate Cygnus X-1 is observed to be in one of two X-ray spectral states; either the low/hard (low soft X-ray flux and a flat power law tail) or high/soft (high blackbody-like soft X-ray flux and a steep power law tail) state. The physical origin of these two states is unclear. We present here a model of an ionized accretion disc, the spectrum of which is blurred by relativistic effects, and fit it to the ASCA, Ginga and EXOSAT data of Cygnus X-1 in both spectral states. We confirm that relativistic blurring provides a much better fit to the low/hard state data and, contrary to some previous results, find the data of both states to be consistent with an ionized thin accretion disc with a reflected fraction of unity extending to the innermost stable circular orbit around the black hole. Our model is an alternative to those which, in the low/hard state, require the accretion disc to be truncated at a few tens of Schwarzschild radii, within which there is a Thomson-thin, hot accretion flow. We suggest a mechanism that may cause the changes in spectral state.

  16. A tidal disruption event in a nearby galaxy hosting an intermediate mass black hole

    SciTech Connect (OSTI)

    Donato, D.; Troja, E.; Pursimo, T.; Cheung, C. C.; Kutyrev, A.; Landt, H.; Butler, N. R.

    2014-02-01

    We report the serendipitous discovery of a bright point source flare in the Abell cluster A1795 with archival EUVE and Chandra observations. Assuming the EUVE emission is associated with the Chandra source, the X-ray 0.5-7 keV flux declined by a factor of ?2300 over a time span of 6 yr, following a power-law decay with index ?2.44 ± 0.40. The Chandra data alone vary by a factor of ?20. The spectrum is well fit by a blackbody with a constant temperature of kT ? 0.09 keV (?10{sup 6} K). The flare is spatially coincident with the nuclear region of a faint, inactive galaxy with a photometric redshift consistent at the 1? level with the cluster (z = 0.062476). We argue that these properties are indicative of a tidal disruption of a star by a black hole (BH) with log (M {sub BH}/M {sub ?}) ? 5.5 ± 0.5. If so, such a discovery indicates that tidal disruption flares may be used to probe BHs in the intermediate mass range, which are very difficult to study by other means.

  17. A grid of synthetic ionizing spectra for very hot compact stars from NLTE model atmospheres

    E-Print Network [OSTI]

    Thomas Rauch

    2003-03-20

    The precise analysis of properties of planetary nebulae is strongly dependent on good models for the stellar ionizing spectrum. Observations in the UV - X-ray wavelength range as well as NLTE model atmosphere calculations of spectra of their exciting stars have shown that neither blackbody fluxes nor "standard" NLTE atmosphere models which are composed out of hydrogen and helium only are good approximations. Strong differences between synthetic spectra from these compared to observed spectra at energies higher than 54 eV (He II ground state) can be ascribed to the neglect of metal-line blanketing. Realistic modeling of the emergent fluxes of hot stars in the UV - X-ray wavelength range requires metal-line blanketed NLTE model atmospheres which include all elements from hydrogen up to the iron-group. For this purpose, we present a grid (solar and halo abundance ratios) of metal-line blanketed NLTE model atmosphere fluxes which covers the parameter range of central stars of planetary nebulae.

  18. Advanced diagnostics for impact-flash spectroscopy on light-gas guns.

    SciTech Connect (OSTI)

    Breiland, William George; Reinhart, William Dodd; Miller, Paul Albert; Brown, Justin L.; Thornhill, Tom Finley, III (,; ); Mangan, Michael A.; Shaner, Eric Arthur; Chhabildas, Lalit Chandra; Grine, Albert D.; Wanke, Michael Clement; Alexander, C. Scott

    2007-03-01

    This study is best characterized as new technology development for implementing new sensors to investigate the optical characteristics of a rapidly expanding debris cloud resulting from hypervelocity impact regimes of 7 to 11 km/s. Our gas guns constitute a unique test bed that match operational conditions relevant to hypervelocity impact encountered in space engagements. We have demonstrated the use of (1) terahertz sensors, (2) silicon diodes for visible regimes, (3) germanium and InGaAs sensors for the near infrared regimes, and (4) the Sandia lightning detectors which are similar to the silicon diodes described in 2. The combination and complementary use of all these techniques has the strong potential of ''thermally'' characterizing the time dependent behavior of the radiating debris cloud. Complementary spectroscopic measurements provide temperature estimates of the impact generated debris by fitting its spectrum to a blackbody radiation function. This debris is time-dependent as its transport/expansion behavior is changing with time. The rapid expansion behavior of the debris cools the cloud rapidly, changing its thermal/temperature characteristics with time. A variety of sensors that span over a wide spectrum, varying from visible regime to THz frequencies, now gives us the potential to cover the impact over a broader temporal regime starting from high pressures (Mbar) high-temperatures (eV) to low pressures (mbar) low temperatures (less than room temperature) as the debris expands and cools.

  19. New Measurement of the Electron Magnetic Moment and the Fine Structure Constant: A First Application of a One-Electron Quantum Cyclotron

    ScienceCinema (OSTI)

    Gabrielse, Gerald [Harvard University, Cambridge, Massachusetts, United States

    2009-09-01

    Remarkably, the famous UW measurement of the electron magnetic moment has stood since 1987. With QED theory, this measurement has determined the accepted value of the fine structure constant. This colloquium is about a new Harvard measurement of these fundamental constants. The new measurement has an uncertainty that is about six times smaller, and it shifts the values by 1.7 standard deviations. One electron suspended in a Penning trap is used for the new measurement, like in the old measurement. What is different is that the lowest quantum levels of the spin and cyclotron motion are resolved, and the cyclotron as well as spin frequencies are determined using quantum jump spectroscopy. In addition, a 0.1 mK Penning trap that is also a cylindrical microwave cavity is used to control the radiation field, to suppress spontaneous emission by more than a factor of 100, to control cavity shifts, and to eliminate the blackbody photons that otherwise stimulate excitations from the cyclotron ground state. Finally, great signal-to-noise for one-quantum transitions is obtained using electronic feedback to realize the first one-particle self-excited oscillator. The new methods may also allow a million times improved measurement of the 500 times small antiproton magnetic moment.

  20. Multi-epoch Analysis of Pulse Shapes from the Neutron Star SAX J1808.4-3658

    E-Print Network [OSTI]

    Sharon M. Morsink; Denis A. Leahy

    2010-11-08

    The pulse shapes detected during multiple outbursts of SAX J1808 are analyzed in order to constrain the neutron star's mass and radius. We use a hot-spot model with a small scattered-light component to jointly fit data from two different epochs, under the restriction that the star's mass and radius and the binary's inclination do not change from epoch to epoch. All other parameters describing the spot location, emissivity, and relative fractions of blackbody to Comptonized radiation are allowed to vary with time. The joint fit of data from the 1998 "slow decay" and the 2002 "end of outburst maximum" epochs using the constraint ineutron star mass 0.8 M_sun 1.0 M_sun from joint fits of the 1998 data with data from other epochs of the 2002 and 2005 outbursts also fall within the same 3 sigma confidence region. This 3 sigma confidence region allows a wide variety of hadronic equations of state, in contrast with an earlier analysis (Leahy et al 2008) of only the 1998 outburst data that only allowed for extremely small stars.

  1. A look with BeppoSAX at the low-luminosity Galactic X-ray source 4U 2206+54

    E-Print Network [OSTI]

    N. Masetti; D. Dal Fiume; L. Amati; S. Del Sordo; F. Frontera; M. Orlandini; E. Palazzi

    2004-05-21

    A pointed observation of the low-luminosity galactic source 4U 2206+54 was carried out in November 1998 with BeppoSAX. The light curve of 4U 2206+54 shows erratic variability on a timescale of about 1 hour; neither hardness variations nor time periodicities are detected throughout this 67 ks long observation. Thanks to the wide spectral coverage capabilities of BeppoSAX we could observe the source X-ray continuum over three energy decades, from 0.6 to 60 keV. The spectrum could be equally well fitted either with a blackbody plus Comptonization or with a high energy cutoff power law. No iron emission around 6.5 keV was detected, while a tentative detection of a cyclotron resonant feature in absorption is presented. Comparison of the present BeppoSAX data with the information available in the literature for this source suggests that 4U 2206+54 is a close binary system in which a (possibly magnetized) NS is accreting from the companion star wind.

  2. Time-dependent, x-ray spectral unfolds and brightness temperatures for intense Li{sup +} ion beam-driven hohlraums

    SciTech Connect (OSTI)

    Fehl, D.L.; Chandler, G.A.; Biggs, F.; Dukart, R.J.; Moats, A.R.; Leeper, R.J.

    1997-01-01

    X-ray-producing hohlraums are being studied as indirect drives for inertial confinement fusion targets. In a 1994 target series on the PBFAII accelerator, cylindrical hohlraum targets were heated by an intense Li{sup +} ion beam and viewed by an array of 13 time-resolved, filtered x-ray detectors (XRDs). The unfold operator (UFO) code and its suite of auxiliary functions were used extensively in obtaining time-resolved x-ray spectra and radiation temperatures from this diagnostic. The UFO was also used to obtain fitted response functions from calibration data, to simulate data from blackbody x-ray spectra of interest, to determine the suitability of various unfolding parameters (e.g., energy domain, energy partition, smoothing conditions, and basis functions), to interpolate the XRD signal traces, and to unfold experimental data. The simulation capabilities of the code were useful in understanding an anomalous feature in the unfolded spectra at low photon energies ({le}100 eV). Uncertainties in the differential and energy-integrated unfolded spectra were estimated from uncertainties in the data. The time{endash}history of the radiation temperature agreed well with independent calculations of the wall temperature in the hohlraum. {copyright} {ital 1997 American Institute of Physics.}

  3. Verification of unfold error estimates in the UFO code

    SciTech Connect (OSTI)

    Fehl, D.L.; Biggs, F.

    1996-07-01

    Spectral unfolding is an inverse mathematical operation which attempts to obtain spectral source information from a set of tabulated response functions and data measurements. Several unfold algorithms have appeared over the past 30 years; among them is the UFO (UnFold Operator) code. In addition to an unfolded spectrum, UFO also estimates the unfold uncertainty (error) induced by running the code in a Monte Carlo fashion with prescribed data distributions (Gaussian deviates). In the problem studied, data were simulated from an arbitrarily chosen blackbody spectrum (10 keV) and a set of overlapping response functions. The data were assumed to have an imprecision of 5% (standard deviation). 100 random data sets were generated. The built-in estimate of unfold uncertainty agreed with the Monte Carlo estimate to within the statistical resolution of this relatively small sample size (95% confidence level). A possible 10% bias between the two methods was unresolved. The Monte Carlo technique is also useful in underdetemined problems, for which the error matrix method does not apply. UFO has been applied to the diagnosis of low energy x rays emitted by Z-Pinch and ion-beam driven hohlraums.

  4. Verification of unfold error estimates in the unfold operator code

    SciTech Connect (OSTI)

    Fehl, D.L.; Biggs, F.

    1997-01-01

    Spectral unfolding is an inverse mathematical operation that attempts to obtain spectral source information from a set of response functions and data measurements. Several unfold algorithms have appeared over the past 30 years; among them is the unfold operator (UFO) code written at Sandia National Laboratories. In addition to an unfolded spectrum, the UFO code also estimates the unfold uncertainty (error) induced by estimated random uncertainties in the data. In UFO the unfold uncertainty is obtained from the error matrix. This built-in estimate has now been compared to error estimates obtained by running the code in a Monte Carlo fashion with prescribed data distributions (Gaussian deviates). In the test problem studied, data were simulated from an arbitrarily chosen blackbody spectrum (10 keV) and a set of overlapping response functions. The data were assumed to have an imprecision of 5{percent} (standard deviation). One hundred random data sets were generated. The built-in estimate of unfold uncertainty agreed with the Monte Carlo estimate to within the statistical resolution of this relatively small sample size (95{percent} confidence level). A possible 10{percent} bias between the two methods was unresolved. The Monte Carlo technique is also useful in underdetermined problems, for which the error matrix method does not apply. UFO has been applied to the diagnosis of low energy x rays emitted by Z-pinch and ion-beam driven hohlraums. {copyright} {ital 1997 American Institute of Physics.}

  5. Time-dependent, x-ray spectral unfolds and brightness temperatures for intense Li{sup +} ion beam-driven hohlraums

    SciTech Connect (OSTI)

    Fehl, D.L.; Chandler, G.A.; Biggs, F.; Dukart, R.J.; Moats, A.R.; Leeper, R.J.

    1996-07-01

    X-ray-producing hohlraums are being studied as indirect drives for Inertial Confinement Fusion targets. In a 1994 target series on the PBFAII accelerator, cylindrical hohlraum targets were heated by an intense Li{sup +} ion beam and viewed by an array of 13 time-resolved, filtered x-ray detectors (XRDs). The UFO unfold code and its suite of auxiliary functions were used extensively in obtaining time- resolved x-ray spectra and radiation temperatures from this diagnostic. UFO was also used to obtain fitted response functions from calibration data, to simulate data from blackbody x-ray spectra of interest, to determine the suitability of various unfolding parameters (e.g., energy domain, energy partition, smoothing conditions, and basis functions), to interpolate the XRD signal traces, and to unfold experimental data. The simulation capabilities of the code were useful in understanding an anomalous feature in the unfolded spectra at low photon energies ({le} 100 eV). Uncertainties in the differential and energy-integrated unfolded spectra were estimated from uncertainties in the data. The time-history of the radiation temperature agreed well with independent calculations of the wall temperature in the hohlraum.

  6. The influence of accretion geometry on the spectral evolution during thermonuclear (type-I) X-ray bursts

    E-Print Network [OSTI]

    Kajava, Jari J E; Latvala, Outi-Marja; Pursiainen, Miika; Poutanen, Juri; Suleimanov, Valery F; Revnivtsev, Mikhail G; Kuulkers, Erik; Galloway, Duncan K

    2014-01-01

    Neutron star (NS) masses and radii can be estimated from observations of photospheric radius-expansion X-ray bursts, provided the chemical composition of the photosphere, the spectral colour-correction factors in the observed luminosity range, and the emission area during the bursts are known. By analysing 246 X-ray bursts observed by the Rossi X-ray Timing Explorer from 11 low-mass X-ray binaries, we find a dependence between the persistent spectral properties and the time evolution of the black body normalisation during the bursts. All NS atmosphere models predict that the colour-correction factor decreases in the early cooling phase when the luminosity first drops below the limiting Eddington value, leading to a characteristic pattern of variability in the measured blackbody normalisation. However, the model predictions agree with the observations for most bursts occurring in hard, low-luminosity, 'island' spectral states, but rarely during soft, high-luminosity, 'banana' states. The observed behaviour may...

  7. Spectrographic temperature measurement of a high power breakdown arc in a high pressure gas switch

    SciTech Connect (OSTI)

    Yeckel, Christopher; Curry, Randy

    2011-09-15

    A procedure for obtaining an approximate temperature value of conducting plasma generated during self-break closure of a RIMFIRE gas switch is described. The plasma is in the form of a breakdown arc which conducts approximately 12 kJ of energy in 1 {mu}s. A spectrographic analysis of the trigger-section of the 6-MV RIMFIRE laser triggered gas switch used in Sandia National Laboratory's ''Z-Machine'' has been made. It is assumed that the breakdown plasma has sufficiently approached local thermodynamic equilibrium allowing a black-body temperature model to be applied. This model allows the plasma temperature and radiated power to be approximated. The gas dielectric used in these tests was pressurized SF{sub 6}. The electrode gap is set at 4.59 cm for each test. The electrode material is stainless steel and insulator material is poly(methyl methacrylate). A spectrum range from 220 to 550 nanometers has been observed and calibrated using two spectral irradiance lamps and three spectrograph gratings. The approximate plasma temperature is reported.

  8. Importance of Compton scattering for radiation spectra of isolated neutron stars with weak magnetic fields

    E-Print Network [OSTI]

    V. Suleimanov; K. Werner

    2007-02-15

    Emergent model spectra of neutron star atmospheres are widely used to fit the observed soft X-ray spectra of different types of isolated neutron stars. We investigate the effect of Compton scattering on the emergent spectra of hot (T_eff > 10^6 K) isolated neutron stars with weak magnetic fields. In order to compute model atmospheres in hydrostatic and radiative equilibrium we solve the radiation transfer equation with the Kompaneets operator. We calculate a set of models with effective temperatures in the range 1 - 5 * 10^6 K, with two values of surface gravity (log g = 13.9 and 14.3) and different chemical compositions. Radiation spectra computed with Compton scattering are softer than those computed without Compton scattering at high energies (E > 5 keV) for light elements (H or He) model atmospheres. The Compton effect is more significant in H model atmospheres and models with low surface gravity. The emergent spectra of the hottest (T_eff > 3 * 10^6 K) model atmospheres can be described by diluted blackbody spectra with hardness factors ~ 1.6 - 1.9. Compton scattering is less important in models with solar abundance of heavy elements.

  9. Resonant Cyclotron Scattering and Comptonization in Neutron Star Magnetospheres

    E-Print Network [OSTI]

    Maxim Lyutikov; Fotis P. Gavriil

    2006-02-10

    Resonant cyclotron scattering of the surface radiation in the magnetospheres of neutron stars may considerably modify the emergent spectra and impede efforts to constraint neutron star properties. Resonant cyclotron scattering by a non-relativistic warm plasma in an inhomogeneous magnetic field has a number of unusual characteristics: (i) in the limit of high resonant optical depth, the cyclotron resonant layer is half opaque, in sharp contrast to the case of non-resonant scattering. (ii) The transmitted flux is on average Compton up-scattered by ~ $1+ 2 beta_T$, where $\\beta_T$ is the typical thermal velocity in units of the velocity of light; the reflected flux has on average the initial frequency. (iii) For both the transmitted and reflected fluxes the dispersion of intensity decreases with increasing optical depth. (iv) The emergent spectrum is appreciably non-Plankian while narrow spectral features produced at the surface may be erased. We derive semi-analytically modification of the surface Plankian emission due to multiple scattering between the resonant layers and apply the model to anomalous X-ray pulsar 1E 1048.1--5937. Our simple model fits just as well as the ``canonical'' magnetar spectra model of a blackbody plus power-law.

  10. Transparency parameters from relativistically expanding outflows

    SciTech Connect (OSTI)

    Bégué, D. [University of Roma "Sapienza," I-00185, p.le A. Moro 5, Rome (Italy); Iyyani, S. [Department of Physics, KTH Royal Institute of Technology, AlbaNova University Center, SE-106 91 Stockholm (Sweden)

    2014-09-01

    In many gamma-ray bursts a distinct blackbody spectral component is present, which is attributed to the emission from the photosphere of a relativistically expanding plasma. The properties of this component (temperature and flux) can be linked to the properties of the outflow and have been presented in the case where there is no sub-photospheric dissipation and the photosphere is in coasting phase. First, we present the derivation of the properties of the outflow for finite winds, including when the photosphere is in the accelerating phase. Second, we study the effect of localized sub-photospheric dissipation on the estimation of the parameters. Finally, we apply our results to GRB 090902B. We find that during the first epoch of this burst the photosphere is most likely to be in the accelerating phase, leading to smaller values of the Lorentz factor than the ones previously estimated. For the second epoch, we find that the photosphere is likely to be in the coasting phase.

  11. 3.6 and 4.5 $\\mu$m Phase Curves of the Highly-Irradiated Eccentric Hot Jupiter WASP-14b

    E-Print Network [OSTI]

    Wong, Ian; Lewis, Nikole K; Kataria, Tiffany; Burrows, Adam; Fortney, Jonathan J; Schwartz, Joel; Agol, Eric; Cowan, Nicolas B; Deming, Drake; Désert, Jean-Michel; Fulton, Benjamin J; Howard, Andrew W; Langton, Jonathan; Laughlin, Gregory; Showman, Adam P; Todorov, Kamen

    2015-01-01

    We present full-orbit phase curve observations of the eccentric ($e$~0.08) transiting hot Jupiter WASP-14b obtained in the 3.6 and 4.5 $\\mu$m bands using the $\\textit{Spitzer Space Telescope}$. We use two different methods for removing the intrapixel sensitivity effect and compare their efficacy in decoupling the instrumental noise. Our measured secondary eclipse depths of 0.1857%$\\pm$0.0104% and 0.2241%$\\pm$0.0087% at 3.6 and 4.5 $\\mu$m, respectively, are both consistent with a blackbody temperature of 2379$\\pm$55 K. We place a $2\\sigma$ upper limit on the nightside flux at 3.6 $\\mu$m and find it to be 10%$\\pm$1% of the dayside flux, corresponding to a 1322$\\pm$212 K difference in brightness temperature. At 4.5 $\\mu$m, the minimum planet flux is 30%$\\pm$3% of the maximum flux, corresponding to a 1016$\\pm$99 K difference in brightness temperature. We compare our measured phase curves to the predictions of one-dimensional radiative transfer and three-dimensional general circulation models. We find that WASP-14...

  12. Testing Loop Quantum Gravity and Electromagnetic Dark Energy in Superconductors

    E-Print Network [OSTI]

    Clovis Jacinto de Matos

    2009-08-06

    In 1989 Cabrera and Tate reported an anomalous excess of mass of the Cooper pairs in rotating thin Niobium rings. So far, this experimental result never received a proper theoretical explanation in the context of superconductor's physics. In the present work we argue that what Cabrera and Tate interpreted as an anomalous excess of mass can also be associated with a deviation from the classical gravitomagnetic Larmor theorem due to the presence of dark energy in the superconductor, as well as with the discrete structure of the area of the superconducting Niobium ring as predicted by Loop Quantum Gravity. From Cabrera and Tate measurements we deduce that the quantization of spacetime in superconducting circular rings occurs at the Planck-Einstein scale $l_{PE} = (\\hbar G/c^3 \\Lambda)^{1/4}\\sim 3.77\\times 10 ^{-5} m$, instead of the Planck scale $l_{P} =(\\hbar G / c^3)^{1/2}=1.61 \\times 10 ^{-35} m$, with an Immirzi parameter which depends on the specific critical temperature of the superconducting material and on the area of the ring. The stephan-Boltzmann law for quantized areas delimited by superconducting rings is predicted, and an experimental concept based on the electromagnetic black-body radiation emitted by this surfaces, is proposed to test loop quantum gravity and electromagnetic dark energy in superconductors.

  13. Stars and statistical physics: a teaching experience

    E-Print Network [OSTI]

    R. Balian; J. -P. Blaizot

    1999-09-20

    The physics of stars, their workings and their evolution, is a goldmine of problems in statistical mechanics and thermodynamics. We discuss many examples that illustrate the possibility of deepening student's knowledge of statistical mechanics by an introductory study of stars. The matter constituting the various stellar objects provides examples of equations of state for classical or quantal and relativistic or non-relativistic gases. Maximum entropy can be used to characterize thermodynamic and gravitational equilibrium which determines the structure of stars and predicts their instability above a certain mass. Contraction accompanying radiation induces either heating or cooling, which explains the formation of stars above a minimum mass. The characteristics of the emitted light are understood from black-body radiation and more precisely from the Boltzmann-Lorentz kinetic equation for photons. The luminosity is governed by the transport of heat by photons from the center to the surface. Heat production by thermonuclear fusion is determined by microscopic balance equations. The stability of the steady state of stars is controlled by the interplay of thermodynamics and gravitation.

  14. Bright Transients from Black Hole - Neutron Star Mergers

    E-Print Network [OSTI]

    D'Orazio, Daniel J; Murray, Norman W; Price, Larry

    2016-01-01

    Direct detection of black hole-neutron star (BHNS) pairs is anticipated with the advent of aLIGO. Electromagnetic counterparts may be crucial for a confident gravitational-wave detection as well as for extraction of astronomical information. Yet BHNS star pairs are notoriously dark and so inaccessible to telescopes. Contrary to this expectation, a bright electromagnetic transient can occur in the final moments before merger as long as the neutron star is highly magnetized. The orbital motion of the neutron star magnet creates a Faraday flux and corresponding power available for luminosity. A spectrum of curvature radiation ramps up until the rapid injection of energy ignites a fireball, which would appear as an energetic blackbody peaking in the X-ray to gamma-rays for neutron star field strengths ranging from $10^{12}$G to $10^{16}$G respectively and a $10M_{\\odot}$ black hole. The fireball event may last from a few milliseconds to a few seconds depending on the NS magnetic field strength, and may be observa...

  15. CONSTRAINTS ON THE SYNCHROTRON SHOCK MODEL FOR THE FERMI GRB 090820A OBSERVED BY GAMMA-RAY BURST MONITOR

    SciTech Connect (OSTI)

    Burgess, J. Michael; Preece, Robert D.; Briggs, Michael S.; Connaughton, Valerie; Guiriec, Sylvain; Paciesas, William S.; Bhat, P. N.; Chaplin, Vandiver; Goldstein, Adam; Baring, Matthew G.; Meegan, Charles A.; Bissaldi, Elisabetta; Diehl, Roland; Greiner, Jochen; Gruber, David; Fishman, Gerald J.; Gibby, Melissa; Giles, Misty E-mail: baring@rice.edu

    2011-11-01

    Discerning the radiative dissipation mechanism for prompt emission in gamma-ray bursts (GRBs) requires detailed spectroscopic modeling that straddles the {nu}F{sub {nu}} peak in the 100 keV-1 MeV range. Historically, empirical fits such as the popular Band function have been employed with considerable success in interpreting the observations. While extrapolations of the Band parameters can provide some physical insight into the emission mechanisms responsible for GRBs, these inferences do not provide a unique way of discerning between models. By fitting physical models directly, this degeneracy can be broken, eliminating the need for empirical functions; our analysis here offers a first step in this direction. One of the oldest, and leading, theoretical ideas for the production of the prompt signal is the synchrotron shock model. Here we explore the applicability of this model to a bright Fermi gamma-ray burst monitor (GBM) burst with a simple temporal structure, GRB 090820A. Our investigation implements, for the first time, thermal and non-thermal synchrotron emissivities in the RMFIT forward-folding spectral analysis software often used in GBM burst studies. We find that these synchrotron emissivities, together with a blackbody shape, provide at least as good a match to the data as the Band GRB spectral fitting function. This success is achieved in both time-integrated and time-resolved spectral fits.

  16. HUBBLE SPACE TELESCOPE DETECTION OF THE DOUBLE PULSAR SYSTEM J0737–3039 IN THE FAR-ULTRAVIOLET

    SciTech Connect (OSTI)

    Durant, Martin; Kargaltsev, Oleg; Pavlov, George G. E-mail: kargaltsev@email.gwu.edu

    2014-03-01

    We report on detection of the double pulsar system J0737–3039 in the far-UV with the Advanced Camera for Surveys/Solar-blind Channel detector aboard Hubble Space Telescope. We measured the energy flux F = (4.6 ± 1.0) × 10{sup –17} erg cm{sup –2} s{sup –1} in the 1250-1550 Å band, which corresponds to the extinction-corrected luminosity L ? 1.5 × 10{sup 28} erg s{sup –1} for the distance d = 1.1 kpc and a plausible reddening E(B – V) = 0.1. If the detected emission comes from the entire surface of one of the neutron stars with a 13 km radius, the surface blackbody temperature is in the range T ? (2-5) × 10{sup 5} K for a reasonable range of interstellar extinction. Such a temperature requires an internal heating mechanism to operate in old neutron stars, or, less likely, it might be explained by heating of the surface of the less energetic Pulsar B by the relativistic wind of Pulsar A. If the far-ultraviolet emission is non-thermal (e.g., produced in the magnetosphere of Pulsar A), its spectrum exhibits a break between the UV and X-rays.

  17. X-RAYING AN ACCRETION DISK IN REALTIME: THE EVOLUTION OF IONIZED REFLECTION DURING A SUPERBURST FROM 4U 1636-536

    SciTech Connect (OSTI)

    Keek, L.; Ballantyne, D. R. [Center for Relativistic Astrophysics, School of Physics, Georgia Institute of Technology, 837 State Street, Atlanta, GA 30332-0430 (United States); Kuulkers, E. [European Space Astronomy Centre (ESA/ESAC), Science Operations Department, E-28691 Villanueva de la Cañada, Madrid (Spain); Strohmayer, T. E., E-mail: l.keek@gatech.edu [X-Ray Astrophysics Lab, Astrophysics Science Division, NASA's Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2014-12-20

    When a thermonuclear X-ray burst ignites on an accreting neutron star, the accretion disk undergoes sudden strong X-ray illumination, which can drive a range of processes in the disk. Observations of superbursts, with durations of several hours, provide the best opportunity to study these processes and to probe accretion physics. Using detailed models of X-ray reflection, we perform time resolved spectroscopy of the superburst observed from 4U 1636-536 in 2001 with the Rossi X-Ray Timing Explorer. The spectra are consistent with a blackbody reflecting off a photoionized accretion disk, with the ionization state dropping with time. The evolution of the reflection fraction indicates that the initial reflection occurs from a part of the disk at larger radius, subsequently transitioning to reflection from an inner region of the disk. Even though this superburst did not reach the Eddington limit, we find that a strong local absorber develops during the superburst. Including this event, only two superbursts have been observed by an instrument with sufficient collecting area to allow for this analysis. It highlights the exciting opportunity for future X-ray observatories to investigate the processes in accretion disks when illuminated by superbursts.

  18. ARM Airborne Continuous carbon dioxide measurements

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Biraud, Sebastien

    2013-03-26

    The heart of the AOS CO2 Airborne Rack Mounted Analyzer System is the AOS Manifold. The AOS Manifold is a nickel coated aluminum analyzer and gas processor designed around two identical nickel-plated gas cells, one for reference gas and one for sample gas. The sample and reference cells are uniquely designed to provide optimal flushing efficiency. These cells are situated between a black-body radiation source and a photo-diode detection system. The AOS manifold also houses flow meters, pressure sensors and control valves. The exhaust from the analyzer flows into a buffer volume which allows for precise pressure control of the analyzer. The final piece of the analyzer is the demodulator board which is used to convert the DC signal generated by the analyzer into an AC response. The resulting output from the demodulator board is an averaged count of CO2 over a specified hertz cycle reported in volts and a corresponding temperature reading. The system computer is responsible for the input of commands and therefore works to control the unit functions such as flow rate, pressure, and valve control.The remainder of the system consists of compressors, reference gases, air drier, electrical cables, and the necessary connecting plumbing to provide a dry sample air stream and reference air streams to the AOS manifold.

  19. SIMULTANEOUS X-RAY AND RADIO OBSERVATIONS OF ROTATING RADIO TRANSIENT J1819-1458

    SciTech Connect (OSTI)

    Miller, J. J.; McLaughlin, M. A. [Department of Physics, West Virginia University, Morgantown, WV 26506 (United States); Rea, N. [Institut de Ciències de l'Espai (IEEC-CSIC) Campus UAB, Fac. de Ciències, Torre C5, parell, 2a planta, E-08193 Barcelona (Spain); Lazaridis, K.; Keane, E. F.; Kramer, M. [Max Planck Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Lyne, A. [Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom)

    2013-10-20

    We present the results of simultaneous radio and X-ray observations of PSR J1819–1458. Our 94 ks XMM-Newton observation of the high magnetic field (?5 × 10{sup 13} G) pulsar reveals a blackbody spectrum (kT ? 130 eV) with a broad absorption feature, possibly composed of two lines at ?1.0 and ?1.3 keV. We performed a correlation analysis of the X-ray photons with radio pulses detected in 16.2 hr of simultaneous observations at 1-2 GHz with the Green Bank, Effelsberg, and Parkes telescopes, respectively. Both the detected X-ray photons and radio pulses appear to be randomly distributed in time. We find tentative evidence for a correlation between the detected radio pulses and X-ray photons on timescales of less than 10 pulsar spin periods, with the probability of this occurring by chance being 0.46%. This suggests that the physical process producing the radio pulses may also heat the polar-cap.

  20. On the sharpness of gamma-ray burst prompt emission spectra

    E-Print Network [OSTI]

    Yu, Hoi-Fung; Greiner, Jochen; Sari, Re'em; Bhat, P Narayana; von Kienlin, Andreas; Paciesas, William S; Preece, Robert D

    2015-01-01

    We aim to obtain a measure of the curvature of time-resolved spectra that can be compared directly to theory. This tests the ability of models such as synchrotron emission to explain the peaks or breaks of GBM prompt emission spectra. We take the burst sample from the official Fermi GBM GRB time-resolved spectral catalog. We re-fit all spectra with a measured peak or break energy in the catalog best-fit models in various energy ranges, which cover the curvature around the spectral peak or break, resulting in a total of 1,113 spectra being analysed. We compute the sharpness angles under the peak or break of the triangle constructed under the model fit curves and compare to the values obtained from various representative emission models: blackbody, single-electron synchrotron, synchrotron emission from a Maxwellian or power-law electron distribution. We find that 35% of the time-resolved spectra are inconsistent with the single-electron synchrotron function, and 91% are inconsistent with the Maxwellian synchrot...

  1. Simultaneous NuSTAR/Chandra observations of the Bursting Pulsar GRO J1744-28 during its third reactivation

    E-Print Network [OSTI]

    Younes, G; Grefenstette, B W; Tomsick, J A; Tennant, A; Finger, M H; Furst, F; Pottschmidt, K; Bhalerao, V; Boggs, S E; Boirin, L; Chakrabarty, D; Christensen, F E; Craig, W W; Degenaar, N; Fabian, A C; Gandhi, P; Gogus, E; Hailey, C J; Harrison, F A; Kennea, J A; Miller, J M; Stern, D; Zhang, W W

    2015-01-01

    We report on a 10 ks simultaneous Chandra/HETG-NuSTAR observation of the Bursting Pulsar, GRO J1744-28, during its third detected outburst since discovery and after nearly 18 years of quiescence. The source is detected up to 60 keV with an Eddington persistent flux level. Seven bursts, followed by dips, are seen with Chandra, three of which are also detected with NuSTAR. Timing analysis reveals a slight increase in the persistent emission pulsed fraction with energy (from 10% to 15%) up to 10 keV, above which it remains constant. The 0.5-70 keV spectra of the persistent and dip emission are the same within errors, and well described by a blackbody (BB), a power-law with an exponential rolloff, a 10 keV feature, and a 6.7 keV emission feature, all modified by neutral absorption. Assuming that the BB emission originates in an accretion disc, we estimate its inner (magnetospheric) radius to be about 4x10^7 cm, which translates to a surface dipole field B~9x10^10 G. The Chandra/HETG spectrum resolves the 6.7 keV ...

  2. X-Ray spectra from protons illuminating a neutron star

    E-Print Network [OSTI]

    B. Deufel; C. P. Dullemond; H. C. Spruit

    2001-08-28

    We consider the interaction of a slowly rotating unmagnetized neutron star with a hot (ion supported, ADAF) accretion flow. The virialized protons of the ADAF penetrate into the neutron star atmosphere, heating a surface layer. Detailed calculations are presented of the equilibrium between heating by the protons, electron thermal conduction, bremsstrahlung and multiple Compton scattering in this layer. Its temperature is of the order 40-70 keV. Its optical depth increases with the incident proton energy flux, and is of the order unity for accretion at $10^{-2}$--$10^{-1}$ of the Eddington rate. At these rates, the X-ray spectrum produced by the layer has a hard tail extending to 100 keV, and is similar to the observed spectra of accreting neutron stars in their hard states. The steep gradient at the base of the heated layer gives rise to an excess of photons at the soft end of the spectrum (compared to a blackbody) through an `inverse photosphere effect'. The differences with respect to previous studies of similar problems are discussed, they are due mostly to a more accurate treatment of the proton penetration process and the vertical structure of the heated layer.

  3. Revisit emission spectrum and entropy quantum of the Reissner-Nordström black hole

    E-Print Network [OSTI]

    Qing-Quan Jiang

    2012-10-15

    Banerjee and Majhi's recent work shows that black hole's emission spectrum could be fully reproduced in the tunneling picture, where, as an intriguing technique, the Kruskal extension was introduced to connect the left and right modes inside and outside the horizon. Some attempt, as an extension, was focused on producing the Hawking emission spectrum of the (charged) Reissner-Nordstr\\"{o}m black hole in the Banerjee-Majhi's treatment. Unfortunately, the Kruskal extension in their observation was so badly defined that the ingoing mode was classically forbidden traveling towards the center of black hole, but could quantum tunnel across the horizon with the probability $\\Gamma=e^{-\\pi \\omega_0/\\kappa_+}$. This tunneling picture is unphysical. With this point as a central motivation, in this paper we first introduce such a suitable Kruskal extension for the (charged) Reissner-Nordstr\\"{o}m black hole that a perfect tunneling picture can be provided during the charged particle's emission. Then, under the new Kruskal extension, we revisit the Hawking emission spectrum and entropy spectroscopy as tunneling from the charged black hole. The result shows that the tunneling method is so universally robust that the Hawking blackbody emission spectrum from a charged black hole can be well reproduced in the tunneling mechanism, and its induced entropy quantum is a much better approximation for the forthcoming quantum gravity theory.

  4. Structure and method for controlling the thermal emissivity of a radiating object

    DOE Patents [OSTI]

    DeSteese, John G.; Antoniak, Zenen I.; White, Michael; Peters, Timothy J.

    2004-03-30

    A structure and method for changing or controlling the thermal emissivity of the surface of an object in situ, and thus, changing or controlling the radiative heat transfer between the object and its environment in situ, is disclosed. Changing or controlling the degree of blackbody behavior of the object is accomplished by changing or controlling certain physical characteristics of a cavity structure on the surface of the object. The cavity structure, defining a plurality of cavities, may be formed by selectively removing material(s) from the surface, selectively adding a material(s) to the surface, or adding an engineered article(s) to the surface to form a new radiative surface. The physical characteristics of the cavity structure that are changed or controlled include cavity area aspect ratio, cavity longitudinal axis orientation, and combinations thereof. Controlling the cavity area aspect ratio may be by controlling the size of the cavity surface area, the size of the cavity aperture area, or a combination thereof. The cavity structure may contain a gas, liquid, or solid that further enhances radiative heat transfer control and/or improves other properties of the object while in service.

  5. Water vapor in the spectrum of the extrasolar planet HD 189733b. II. The eclipse

    SciTech Connect (OSTI)

    Crouzet, Nicolas; McCullough, Peter R.; Deming, Drake; Madhusudhan, Nikku

    2014-11-10

    Spectroscopic observations of exoplanets are crucial to infer the composition and properties of their atmospheres. HD 189733b is one of the most extensively studied exoplanets and is a cornerstone for hot Jupiter models. In this paper, we report the dayside emission spectrum of HD 189733b in the wavelength range 1.1-1.7 ?m obtained with the Hubble Space Telescope Wide Field Camera 3 (WFC3) in spatial scan mode. The quality of the data is such that even a straightforward analysis yields a high-precision Poisson noise-limited spectrum: the median 1? uncertainty is 57 ppm per 0.02 ?m bin. We also build a white-light curve correcting for systematic effects and derive an absolute eclipse depth of 96 ± 39 ppm. The resulting spectrum shows marginal evidence for water vapor absorption, but can also be well explained by a blackbody spectrum. However, the combination of these WFC3 data with previous Spitzer photometric observations is best explained by a dayside atmosphere of HD 189733b with no thermal inversion and a nearly solar or subsolar H{sub 2}O abundance in a cloud-free atmosphere. Alternatively, this apparent subsolar abundance may be the result of clouds or hazes that future studies need to investigate.

  6. Dust temperature and CO-to-H2 conversion factor variations in the SFR-M* plane

    E-Print Network [OSTI]

    Magnelli, B; Lutz, D; Tacconi, L J; Berta, S; Bournaud, F; Charmandaris, V; Dannerbauer, H; Elbaz, D; Förster-Schreiber, N M; Graciá-Carpio, J; Ivison, R; Maiolino, R; Nordon, R; Popesso, P; Rodighiero, G; Santini, P; Wuyts, S

    2012-01-01

    Deep Herschel imaging and 12CO(2-1) line luminosities from the IRAM PdBI are combined for a sample of 17 galaxies at z>1 from the GOODS-N field. The sample includes galaxies both on and above the main sequence (MS) traced by star-forming galaxies in the SFR-M* plane. The far-infrared data are used to derive dust masses, Mdust. Combined with an empirical prescription for the dependence of the gas-to-dust ratio on metallicity (GDR), the CO luminosities and Mdust values are used to derive for each galaxy the CO-to-H2 conversion factor, alpha_co. Like in the local Universe, the value of alpha_co is a factor of ~5 smaller in starbursts compared to normal star-forming galaxies (SFGs). We also uncover a relation between alpha_co and dust temperature (Tdust; alpha_co decreasing with increasing Tdust) as obtained from modified blackbody fits to the far-infrared data. While the absolute normalization of the alpha_co(Tdust) relation is uncertain, the global trend is robust against possible systematic biases in the deter...

  7. Probing the cosmic microwave background temperature using the Sunyaev-Zeldovich effect

    E-Print Network [OSTI]

    Cathy Horellou; Martin Nord; Daniel Johansson; Anna Levy

    2005-07-01

    We discuss the possibility to constrain the relation between redshift and temperature of the cosmic microwave background (CMB) using multifrequency Sunyaev-Zeldovich (SZ) observations. We have simulated a catalog of clusters of galaxies detected through their SZ signature assuming the sensitivities that will be achieved by the {\\it Planck} satellite at 100, 143 and 353 GHz, taking into account the instrumental noise and the contamination from the Cosmic Infrared Background and from unresolved radiosources. We have parametrized the cosmological temperature-redshift law as $T\\propto (1+z)^{(1-a)}$. Using two sets of SZ flux density ratios (100/143 GHz, which is most sensitive to the parametrization of the $T-z$ law, and 143/353 GHz, which is most sensitive to the peculiar velocities of the clusters) we show that it is possible to recover the $T-z$ law assuming that the temperatures and redshifts of the clusters are known. From a simulated catalog of $\\sim 1200$ clusters, the parameter $a$ can be recovered to an accuracy of 10$^{-2}$. Sensitive SZ observations thus appear as a potentially useful tool to test the standard law. Most cosmological models predict a linear variation of the CMB temperature with redshift. The discovery of an alternative law would have profound implications on the cosmological model, implying creation of energy in a manner that would still maintain the black-body shape of the CMB spectrum at redshift zero.

  8. Type IIP supernovae as cosmological probes: A SEAM distance to SN1999em

    SciTech Connect (OSTI)

    Baron, E.; Nugent, Peter E.; Branch, David; Hauschildt, Peter H.

    2004-06-01

    Because of their intrinsic brightness, supernovae make excellent cosmological probes. We describe the spectral-fitting expanding atmosphere method (SEAM) for obtaining distances to Type IIP supernovae (SNe IIP) and present a distance to SN 1999em for which a Cepheid distance exists. Our models give results consistent with the Cepheid distance, even though we have not attempted to tune the underlying hydrodynamical model but have simply chosen the best fits. This is in contradistinction to the expanding photosphere method (EPM), which yields a distance to SN 1999em that is 50 percent smaller than the Cepheid distance. We emphasize the differences between the SEAM and the EPM. We show that the dilution factors used in the EPM analysis were systematically too small at later epochs. We also show that the EPM blackbody assumption is suspect. Since SNe IIP are visible to redshifts as high as z {approx}< 6, with the James Webb Space Telescope, the SEAM may be a valuable probe of the early universe.

  9. A Hybrid Design of Project-X

    SciTech Connect (OSTI)

    Chou, W.; /Fermilab

    2009-05-01

    Project-X is a leading candidate of the next major accelerator construction project at Fermilab. The mission need of Project-X is to establish an intensity frontier for particle physics research, or more precisely, to build a multi-MW proton source for neutrino and other particle studies. Coupled with an upgraded Main Injector (MI) and Recycler, an 8 GeV superconducting RF (SRF) H- linac meets this need. However, a more cost effective approach would be a hybrid design, namely, a combination of a 2 GeV SRF linac and an 8 GeV rapid cycling synchrotron (RCS) in lieu of an 8 GeV SRF linac. This alternative design also meets the mission need but at a lower cost since a synchrotron is cheaper than a SRF linac. It retains the ability to use a 2 GeV SRF linac for ILC technology development. It reuses the existing Debuncher enclosure and Booster RF. The transport line of 2 GeV H- particles is shorter than the present 8 GeV design since stronger bending magnets can be used. The blackbody radiation stripping of H- particles will no longer be a problem and the requirement of a cryogenic beam screen can be eliminated. The efficiency of stripping foil is higher and injection loss (kJ) will be reduced by a factor of 4. This paper introduces this alternative design and describes briefly the major components in the design.

  10. Little Black Holes as Dark Matter Candidates with Feasible Cosmic and Terrestrial Interactions

    E-Print Network [OSTI]

    Mario Rabinowitz

    2005-03-09

    Little black holes (LBH) contribute to the accelerated expansion of the Universe, and interact with stars, neutron stars, and planets. A range of proposals are reviewed in which LBH are considered to be a component of dark matter/dark energy. A LBH is a candidate for the 1908 devastation of Tungus Siberia, as important LBH interactions were overlooked. LBH passing through neutron star pulsars are capable of causing a change in. Energy input due to the passage of LBH through the earth, sun, and neutron stars is examined to determine if they could initiate tremors and quakes in such bodies. In encounters with the earth.s atmosphere, LBH can manifest themselves as the core energy source of ball lightning (BL). Relating the LBH incidence rate on earth to BL occurrence has the potential of shedding light on the distribution of LBH in the universe, and their velocities relative to the earth. Most BL features can be explained by a testable LBH model. The total number of degrees of freedom of a d-dimensional body in n-space is derived so that equipartition of energy may be applied in the early universe. Blackbody and Hawking radiation are generalized to n-space. The entropy of LBH and of the universe are examined. The largest possible attractive force, repulsive force, and luminosity in nature are considered in the context of LBH. A question is raised as to whether the Planck scale is truly fundamental. The gravitational fine structure constant is re-examined.

  11. Models of neutron star atmospheres enriched with nuclear burning ashes

    E-Print Network [OSTI]

    Nättilä, Joonas; Kajava, Jari J E; Poutanen, Juri

    2015-01-01

    Low-mass X-ray binaries hosting neutron stars (NS) exhibit thermonuclear (type-I) X-ray bursts, which are powered by unstable nuclear burning of helium and/or hydrogen into heavier elements deep in the NS "ocean". In some cases the burning ashes may rise from the burning depths up to the NS photosphere by convection, leading to the appearance of the metal absorption edges in the spectra, which then force the emergent X-ray burst spectra to shift toward lower energies. These effects may have a substantial impact on the color correction factor $f_c$ and the dilution factor $w$, the parameters of the diluted blackbody model $F_E \\approx w B_E(f_c T_{eff})$ that is commonly used to describe the emergent spectra from NSs. The aim of this paper is to quantify how much the metal enrichment can change these factors. We have developed a new NS atmosphere modeling code, which has a few important improvements compared to our previous code required by inclusion of the metals. The opacities and the internal partition func...

  12. ON THE X-RAY EMISSION MECHANISMS OF THE PERSISTENT SOURCE AND VERY LOW FLUENCE BURSTS OF SGR J0501+4516

    SciTech Connect (OSTI)

    Lin Lin; Goegues, Ersin; Guever, Tolga [Faculty of Engineering and Natural Sciences, Sabanc Latin-Small-Letter-Dotless-I University, Orhanl Latin-Small-Letter-Dotless-I -Tuzla, Istanbul 34956 (Turkey); Kouveliotou, Chryssa, E-mail: linlin@sabanciuniv.edu [Science and Technology Office, ZP12, NASA Marshall Space Flight Center, Huntsville, AL 35812 (United States)

    2012-12-20

    We present here a detailed spectral study of the X-ray emission of the persistent source and the low-fluence bursts of SGR J0501+4516 observed during a deep XMM-Newton observation near the peak of its 2008 outburst. For the persistent emission, we employ a physically motivated continuum emission model and spectroscopically determine important source properties such as the surface magnetic field strength and the magnetospheric scattering optical depth. We find that the magnetar surface temperature near the peak of its activity is 0.38 keV, corresponding to an emission area of 131 km{sup 2} at a distance of 2 kpc. The surface magnetic field strength determined spectroscopically, B = 2.2 Multiplication-Sign 10{sup 14} G, is consistent with the dipole field strength inferred from the source spin and spin-down rate. We fit the stacked spectra of 129 very faint bursts with a modified blackbody model and find a temperature of 1.16 keV, corresponding to an emission area of 93 km{sup 2}. We also find evidence for cooling during the burst decay phase.

  13. Extreme Environment Silicon Carbide Hybrid Temperature & Pressure Optical Sensors

    SciTech Connect (OSTI)

    Nabeel Riza

    2010-09-01

    This final report contains the main results from a 3-year program to further investigate the merits of SiC-based hybrid sensor designs for extreme environment measurements in gas turbines. The study is divided in three parts. Part 1 studies the material properties of SiC such as temporal response, refractive index change with temperature, and material thermal response reversibility. Sensor data from a combustion rig-test using this SiC sensor technology is analyzed and a robust distributed sensor network design is proposed. Part 2 of the study focuses on introducing redundancy in the sensor signal processing to provide improved temperature measurement robustness. In this regard, two distinct measurement methods emerge. A first method uses laser wavelength sensitivity of the SiC refractive index behavior and a second method that engages the Black-Body (BB) radiation of the SiC package. Part 3 of the program investigates a new way to measure pressure via a distance measurement technique that applies to hot objects including corrosive fluids.

  14. The role of star-formation and AGN in dust heating of z = 0.3-2.8 galaxies - I. Evolution with redshift and luminosity

    E-Print Network [OSTI]

    Kirkpatrick, Allison; Sajina, Anna; Roebuck, Eric; Yan, Lin; Armus, Lee; Diaz-Santos, Tanio; Stierwalt, Sabrina

    2015-01-01

    We characterize infrared spectral energy distributions of 343 (Ultra) Luminous Infrared Galaxies from $z=0.3-2.8$. We diagnose the presence of an AGN by decomposing individual Spitzer mid-IR spectroscopy into emission from star-formation and an AGN-powered continuum; we classify sources as star-forming galaxies (SFGs), AGN, or composites. Composites comprise 30% of our sample and are prevalent at faint and bright $S_{24}$, making them an important source of IR AGN emission. We combine spectroscopy with multiwavelength photometry, including Herschel imaging, to create three libraries of publicly available templates (2-1000 $\\mu$m). We fit the far-IR emission using a two temperature modified blackbody to measure cold and warm dust temperatures ($T_c$ and $T_w$). We find that $T_c$ does not depend on mid-IR classification, while $T_w$ shows a notable increase as the AGN grows more luminous. We measure a quadratic relationship between mid-IR AGN emission and total AGN contribution to $L_{\\rm IR}$. AGN, composites...

  15. Swift X-ray and UV monitoring of the Classical Nova V458 Vul (Nova Vul 2007)

    E-Print Network [OSTI]

    Ness, J -U; Beardmore, A P; Boyd, D; Bode, M F; Brady, S; Evans, P A; Gänsicke, B T; Kitamoto, S; Knigge, C; Miller, I; Osborne, J P; Page, K L; Rodríguez-Gil, P; Schwarz, G; Staels, B; Steeghs, D; Takei, D; Tsujimoto, M; Wesson, R; Zijlstra, A

    2009-01-01

    We describe the highly variable X-ray and UV emission of V458 Vul (Nova Vul 2007), observed by Swift between 1 and 422 days after outburst. Initially bright only in the UV, V458 Vul became a variable hard X-ray source due to optically thin thermal emission at kT=0.64 keV with an X-ray band unabsorbed luminosity of 2.3x10^{34} erg s^{-1} during days 71-140. The X-ray spectrum at this time requires a low Fe abundance (0.2^{+0.3}_{-0.1} solar), consistent with a Suzaku measurement around the same time. On day 315 we find a new X-ray spectral component which can be described by a blackbody with temperature of kT=23^{+9}_{-5} eV, while the previous hard X-ray component has declined by a factor of 3.8. The spectrum of this soft X-ray component resembles those typically seen in the class of supersoft sources (SSS) which suggests that the nova ejecta were starting to clear and/or that the WD photosphere is shrinking to the point at which its thermal emission reaches into the X-ray band. We find a high degree of varia...

  16. X- and ?-ray pulsations of the nearby radio-faint PSR J1741–2054

    SciTech Connect (OSTI)

    Marelli, M.; Belfiore, A.; Caraveo, P.; De Luca, A.; Salvetti, D. [INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica Milano, via E. Bassini 15, I-20133 Milano (Italy); Saz Parkinson, P. [Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, CA 95064 (United States); Sarazin, C.; Sivakoff, G. R. [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States); Camilo, F., E-mail: marelli@lambrate.inaf.it [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States)

    2014-07-20

    We report the results of a deep XMM-Newton observation of the radio-faint ?-ray pulsar J1741–2054 and its nebula together with the analysis of five years of Fermi Large Area Telescope (LAT) data. The X-ray spectrum of the pulsar is consistent with an absorbed power law plus a blackbody, originating at least partly from the neutron star cooling. The nebular emission is consistent with that of a synchrotron pulsar wind nebula, with hints of spatial spectral variation. We extended the available Fermi LAT ephemeris and folded the ?-ray and X-ray data. We detected X-ray pulsations from the neutron star: both the thermal and non-thermal components are ?35%-40% pulsed, with phase-aligned maxima. A sinusoid fits the thermal-folded profile well. A 10 bin phase-resolved analysis of the X-ray emission shows softening of the non-thermal spectrum during the on-pulse phases. The radio, X-ray, and ?-ray light curves are single-peaked, not phase-aligned, with the X-ray peak trailing the ?-ray peak by more than half a rotation. Spectral considerations suggest that the most probable pulsar distance is in the 0.3-1.0 kpc range, in agreement with the radio dispersion measure.

  17. Temperature Profiles and the Effect of AGN on Submillimeter Emission from BLAST Observations of Resolved Galaxies

    E-Print Network [OSTI]

    Wiebe, Donald V; Bock, James J; Chapin, Edward L; Devlin, Mark J; Dicker, Simon; Griffin, Matthew; Gundersen, Joshua O; Halpern, Mark; Hargrave, Peter C; Hughes, David H; Klein, Jeff; Marsden, Gaelen; Martin, Peter G; Mauskopf, Philip; Netterfield, Calvin B; Olmi, Luca; Pascale, Enzo; Patanchon, Guillaume; Rex, Marie; Scott, Douglas; Semisch, Christopher; Thomas, Nicholas; Truch, Matthew D P; Tucker, Carole; Tucker, Gregory S; Viero, Marco P

    2009-01-01

    Over the course of two flights, the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) made resolved maps of seven nearby (<25 Mpc) galaxies at 250, 350, and 500 microns. During its June 2005 flight from Sweden (BLAST05), BLAST observed a single nearby galaxy, NGC 4565. During the December 2006 flight from Antarctica (BLAST06), BLAST observed the nearby galaxies NGC 1097, NGC 1291, NGC 1365, NGC 1512, NGC 1566, and NGC 1808. We fit physical dust models to a combination of BLAST observations and other available data for the the galaxies with Spitzer data. We fit a modified blackbody to the remaining galaxies to obtain total dust mass and mean dust temperature. For the four galaxies with Spitzer data, we also produce maps and radial profiles of dust column density and temperature. We measure the fraction of BLAST detected flux originating from the central cores of these galaxies and use this to calculate a "core fraction", an upper limit on the "AGN fraction" of submillimeter detected galaxies. Fin...

  18. Evidence for Environmental Changes in the Submillimeter Dust Opacity

    E-Print Network [OSTI]

    Martin, Peter G; Bontemps, Sylvain; Miville-Deschênes, Marc-Antoine; Ade, Peter A R; Bock, James J; Chapin, Edward L; Devlin, Mark J; Dicker, Simon R; Griffin, Matthew; Gundersen, Joshua O; Halpern, Mark; Hargrave, Peter C; Hughes, David H; Klein, Jeff; Marsden, Gaelen; Mauskopf, Philip; Netterfield, Calvin B; Olmi, Luca; Patanchon, Guillaume; Rex, Marie; Scott, Douglas; Semisch, Christopher; Truch, Matthew D P; Tucker, Carole; Tucker, Gregory S; Viero, Marco P; Wiebe, Donald V

    2011-01-01

    The submillimeter opacity of dust in the diffuse Galactic interstellar medium (ISM) has been quantified using a pixel-by-pixel correlation of images of continuum emission with a proxy for column density. We used three BLAST bands at 250, 350, and 500 \\mu m and one IRAS at 100 \\mu m. The proxy is the near-infrared color excess, E(J-Ks), obtained from 2MASS. Based on observations of stars, we show how well this color excess is correlated with the total hydrogen column density for regions of moderate extinction. The ratio of emission to column density, the emissivity, is then known from the correlations, as a function of frequency. The spectral distribution of this emissivity can be fit by a modified blackbody, whence the characteristic dust temperature T and the desired opacity \\sigma_e(1200) at 1200 GHz can be obtained. We have analyzed 14 regions near the Galactic plane toward the Vela molecular cloud, mostly selected to avoid regions of high column density (N_H > 10^{22} cm^-2) and small enough to ensure a u...

  19. Role of the H$_2^+$ channel in the primordial star formation under strong radiation field and the critical intensity for the supermassive star formation

    E-Print Network [OSTI]

    Sugimura, Kazuyuki; Omukai, Kazuyuki; Galli, Daniele; Palla, Francesco

    2015-01-01

    We investigate the role of the H_2^+ channel on H_2 molecule formation during the collapse of primordial gas clouds immersed in strong radiation fields which are assumed to have the shape of a diluted black-body spectra with temperature T_rad. Since the photodissociation rate of H_2^+ depends on its level population, we take full account of the vibrationally-resolved H_2^+ kinetics. We find that in clouds under soft but intense radiation fields with spectral temperature T_rad 7000 K, the H^- channel takes over H_2^+ in the production of molecular hydrogen. We calculate the critical radiation intensity needed for supermassive star formation by direct collapse and examine its dependence on the H_2^+ level population. Under the assumption of local thermodynamic equilibrium (LTE) level population, the critical intensity is underestimated by a factor of a few for soft spectra with T_rad < 7000 K. For harder spectra, the value of the critical intensity is not affected by the level population of H_2^+. This resu...

  20. On the triple peaks of SNHunt248 in NGC 5806

    E-Print Network [OSTI]

    Kankare, E; Pastorello, A; Fraser, M; Mattila, S; Smartt, S J; Bruce, A; Chambers, K C; Elias-Rosa, N; Flewelling, H; Fremling, C; Harmanen, J; Huber, M; Jerkstrand, A; Kangas, T; Kuncarayakti, H; Magee, M; Magnier, E; Polshaw, J; Smith, K W; Sollerman, J; Tomasella, L

    2015-01-01

    We present our findings on a supernova (SN) impostor, SNHunt248, based on optical and near-IR data spanning $\\sim$15 yrs before discovery, to $\\sim$1 yr post-discovery. The light curve displays three distinct peaks, the brightest of which is at $M_{R} \\sim -15.0$ mag. The post-discovery evolution is consistent with the ejecta from the outburst interacting with two distinct regions of circumstellar material. The 0.5 - 2.2 $\\mu$m spectral energy distribution at -740 d is well-matched by a single 6700 K blackbody with $\\log(L/L_\\odot) \\sim 6.1$. This temperature and luminosity support previous suggestions of a yellow hypergiant progenitor; however, we find it to be brighter than the brightest and most massive Galactic late-F to early-G spectral type hypergiants. Overall the historical light curve displays variability of up to $\\sim \\pm1$ mag. At current epochs ($\\sim$1 yr post-outburst), the absolute magnitude ($M_{R} \\sim -9$ mag) is just below the faintest observed historical absolute magnitude $\\sim$10 yrs be...

  1. Probing the terrestrial regions of planetary systems: warm debris disks with emission features

    SciTech Connect (OSTI)

    Ballering, Nicholas P.; Rieke, George H.; Gáspár, András, E-mail: ballerin@email.arizona.edu [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)

    2014-09-20

    Observations of debris disks allow for the study of planetary systems, even where planets have not been detected. However, debris disks are often only characterized by unresolved infrared excesses that resemble featureless blackbodies, and the location of the emitting dust is uncertain due to a degeneracy with the dust grain properties. Here, we characterize the Spitzer Infrared Spectrograph spectra of 22 debris disks exhibiting 10 ?m silicate emission features. Such features arise from small warm dust grains, and their presence can significantly constrain the orbital location of the emitting debris. We find that these features can be explained by the presence of an additional dust component in the terrestrial zones of the planetary systems, i.e., an exozodiacal belt. Aside from possessing exozodiacal dust, these debris disks are not particularly unique; their minimum grain sizes are consistent with the blowout sizes of their systems, and their brightnesses are comparable to those of featureless warm debris disks. These disks are in systems of a range of ages, though the older systems with features are found only around A-type stars. The features in young systems may be signatures of terrestrial planet formation. Analyzing the spectra of unresolved debris disks with emission features may be one of the simplest and most accessible ways to study the terrestrial regions of planetary systems.

  2. The Spectrum and Accurate Location of GRS 1758-258

    E-Print Network [OSTI]

    W. A. Heindl; D. M. Smith

    2001-07-24

    We observed the "micro-quasar" GRS 1758-258 four times with Chandra. Two HRC-I observations were made in 2000 September-October spanning an intermediate-to-hard spectral transition (identified with RXTE). Another HRC-I and an ACIS/HETGS observation were made in 2001 March following a hard-to-soft transition to a very low flux state. The accurate position (J2000) of the X-ray source is RA= 18 01 12.40, Dec= -25 44 36.0 (90% confidence radius = 0".6), consistent with the purported variable radio counterpart. All images are consistent with GRS 1758-258 being a point source, indicating that any bright jet is less than ~1 light-month in projected length, assuming a distance of 8.5 kpc. The March spectrum is well-fit with a multi-color disk-blackbody with an inner temperature of 0.50+/-0.01 keV, interstellar absorption of nH = (1.59 +/- 0.05)x10^22 cm^-2, and (un-absorbed) 1-10 keV luminosity of (4.5x10^36)(D/8.5kpc)^2 ergs/sec. No narrow emission lines are apparent in the spectrum and upper limits to line equivalent widths are given.

  3. X-ray analysis of the proper motion and pulsar wind nebula for PSR J1741-2054

    E-Print Network [OSTI]

    Auchettl, Katie; Romani, Roger W; Posselt, Bettina; Pavlov, George G; Kargaltsev, Oleg; Ng, C-Y; Temim, Tea; Weisskopf, Martin C; Bykov, Andrei; Swartz, Douglas A

    2015-01-01

    We obtained six observations of PSR J1741-2054 using the $Chandra$ ACIS-S detector totaling $\\sim$300 ks. By registering this new epoch of observations to an archival observation taken 3.2 years earlier using X-ray point sources in the field of view, we have measured the pulsar proper motion at $\\mu =109 \\pm 10$ mas/yr. The spectrum of the pulsar can be described by an absorbed power law with photon index $\\Gamma$=2.68$\\pm$0.04, plus a blackbody with an emission radius of (4.5$^{+3.2}_{-2.5})d_{0.38}$ km, for a DM-estimated distance of $0.38d_{0.38}$ kpc and a temperature of $61.7\\pm3.0$ eV. Emission from the compact nebula is well described by an absorbed power law model with a photon index of $\\Gamma$ = 1.67$\\pm$0.06, while the diffuse emission seen as a trail extending northeast of the pulsar shows no evidence of synchrotron cooling. We also looked for extended features that might represent a jet or torus-like structure using image deconvolution and PSF-subtraction but we find no conclusive evidence of suc...

  4. ARM Airborne Continuous carbon dioxide measurements

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Biraud, Sebastien

    The heart of the AOS CO2 Airborne Rack Mounted Analyzer System is the AOS Manifold. The AOS Manifold is a nickel coated aluminum analyzer and gas processor designed around two identical nickel-plated gas cells, one for reference gas and one for sample gas. The sample and reference cells are uniquely designed to provide optimal flushing efficiency. These cells are situated between a black-body radiation source and a photo-diode detection system. The AOS manifold also houses flow meters, pressure sensors and control valves. The exhaust from the analyzer flows into a buffer volume which allows for precise pressure control of the analyzer. The final piece of the analyzer is the demodulator board which is used to convert the DC signal generated by the analyzer into an AC response. The resulting output from the demodulator board is an averaged count of CO2 over a specified hertz cycle reported in volts and a corresponding temperature reading. The system computer is responsible for the input of commands and therefore works to control the unit functions such as flow rate, pressure, and valve control.The remainder of the system consists of compressors, reference gases, air drier, electrical cables, and the necessary connecting plumbing to provide a dry sample air stream and reference air streams to the AOS manifold.

  5. Thermal emission and absorption of radiation in finite inverted-opal photonic crystals

    SciTech Connect (OSTI)

    Florescu, Marian; Stimpson, Andrew J.; Lee, Hwang; Dowling, Jonathan

    2005-09-15

    We study theoretically the optical properties of a finite inverted-opal photonic crystal. The light-matter interaction is strongly affected by the presence of the three-dimensional photonic crystal and the alterations of the light emission and absorption processes can be used to suppress or enhance the thermal emissivity and absorptivity of the dielectric structure. We investigate the influence of the absorption present in the system on the relevant band edge frequencies that control the optical response of the photonic crystal. Our study reveals that the absorption processes cause spectral broadening and shifting of the band edge optical resonances, and determine a strong reduction of the photonic band gap spectral range. Using the angular and spectral dependence of the band edge frequencies for stop bands along different directions, we argue that by matching the blackbody emission spectrum peak with a prescribed maximum of the absorption coefficient, it is possible to achieve an angle-sensitive enhancement of the thermal emission/absorption of radiation. This result opens a way to realize a frequency-sensitive and angle-sensitive photonic crystal absorbers/emitters.

  6. Suzaku X-Ray Spectroscopy of a Peculiar Hot Star in the Galactic Center Region

    E-Print Network [OSTI]

    Yoshiaki Hyodo; Masahiro Tsujimoto; Katsuji Koyama; Shogo Nishiyama; Tetsuya Nagata; Itsuki Sakon; Hiroshi Murakami; Hironori Matsumoto

    2007-12-03

    We present the results of a Suzaku study of a bright point-like source in the 6.7 keV intensity map of the Galactic center region. We detected an intense FeXXV 6.7 keV line with an equivalent width of ~1 keV as well as emission lines of highly ionized Ar and Ca from a spectrum obtained by the X-ray Imaging Spectrometer. The overall spectrum is described very well by a heavily absorbed (~2x10^{23}cm^{-2}) thin thermal plasma model with a temperature of 3.8+/-0.6 keV and a luminosity of ~3x10^{34} erg s^{-1} (2.0--8.0 keV) at 8 kpc. The absorption, temperature, luminosity, and the 6.7 keV line intensity were confirmed with the archived XMM-Newton data. The source has a very red (J-Ks=8.2 mag) infrared spectral energy distribution (SED), which was fitted by a blackbody emission of ~1000 K attenuated by a visual extinction of ~31 mag. The high plasma temperature and the large X-ray luminosity are consistent with a wind-wind colliding Wolf-Rayet binary. The similarity of the SED to those of the eponymous Quintuplet cluster members suggests that the source is a WC-type source.

  7. Pulse-phase spectroscopy of SMC X-1 with Chandra and XMM-Newton: reprocessing by a precessing disk?

    E-Print Network [OSTI]

    R. C. Hickox; S. D. Vrtilek

    2005-08-11

    We present pulse-phase X-ray spectroscopy of the high-mass X-ray pulsar SMC X-1 from five different epochs, using Chandra X-ray Observatory ACIS-S and XMM-Newton EPIC-pn data. The X-ray spectrum consistently shows two distinct components, a hard power law and a soft blackbody with kT_BB ~ 0.18 keV. For all five epochs the hard component shows a simple double-peaked pulse shape, and also a variation in the power law slope, which becomes harder at maximum flux and softer at minimum flux. For the soft component, the pulse profile changes between epochs, in both shape and phase relative to the power law pulses. The soft component is likely produced by reprocessing of the hard X-ray pulsar beam by the inner accretion disk. We use a model of a twisted inner disk, illuminated by the rotating X-ray pulsar beam, to simulate pulsations in the soft component due to this reprocessing. We find that for some disk and beam geometries, precession of an illuminated accretion disk can roughly reproduce the observed long-term changes in the soft pulse profiles.

  8. Innovative Development of Next Generation and Energy Efficient Solid State Light Sources for General Illumination

    SciTech Connect (OSTI)

    Ian Ferguson

    2006-07-31

    This two year program resulted in a novel broadband spectrally dynamic solid state illumination source (BSDLED) that uses a dual wavelength light emitting diode (LED) and combinations of phosphors to create a broadband emission that is real-time controllable. Four major focuses of this work were as follows: (1) creation of a two terminal dual wavelength LED with control of the relative intensities of the two emission peaks, (2) bandgap modeling of the two terminal dual LED to explain operation based on the doping profile, (3) novel use of phosphor combinations with dual LEDs to create a broadband spectral power distribution that can be varied to mimic a blackbody radiator over a certain range and (4) investigation of novel doping schemes to create tunnel junctions or equivalent buried current spreading layers in the III-nitrides. Advances were achieved in each of these four areas which could lead to more efficient solid state light sources with greater functionality over existing devices. The two-terminal BSDLED is an important innovation for the solid-state lighting industry as a variable spectrum source. A three-terminal dual emitter was also investigated and appears to be the most viable approach for future spectrally dynamic solid state lighting sources. However, at this time reabsorption of emission between the two active regions limits the usefulness of this device for illumination applications.

  9. MULTIWAVELENGTH OBSERVATIONS OF A0620-00 IN QUIESCENCE

    SciTech Connect (OSTI)

    Froning, Cynthia S.; France, Kevin; Khargharia, Juthika [Center for Astrophysics and Space Astronomy, University of Colorado, 593 UCB, Boulder, CO 80309-0593 (United States); and others

    2011-12-10

    We present contemporaneous X-ray, ultraviolet, optical, near-infrared, and radio observations of the black hole binary system, A0620-00, acquired in 2010 March. Using the Cosmic Origins Spectrograph on the Hubble Space Telescope, we have obtained the first FUV spectrum of A0620-00 as well as NUV observations with the Space Telescope Imaging Spectrograph. The observed spectrum is flat in the FUV and very faint (with continuum fluxes {approx_equal} 1e - 17 erg cm{sup -2} s{sup -1} A{sup -1}). The UV spectra also show strong, broad (FWHM {approx} 2000 km s{sup -1}) emission lines of Si IV, C IV, He II, Fe II, and Mg II. The C IV doublet is anomalously weak compared to the other lines, which is consistent with the low carbon abundance seen in NIR spectra of the source. Comparison of these observations with previous NUV spectra of A0620-00 shows that the UV flux has varied by factors of 2-8 over several years. We compiled the dereddened, broadband spectral energy distribution (SED) of A0620-00 and compared it to previous SEDs as well as theoretical models. The SEDs show that the source varies at all wavelengths for which we have multiple samples. Contrary to previous observations, the optical-UV spectrum does not continue to drop to shorter wavelengths, but instead shows a recovery and an increasingly blue spectrum in the FUV. We created an optical-UV spectrum of A0620-00 with the donor star contribution removed. The non-stellar spectrum peaks at {approx_equal}3000 A. The peak can be fit with a T = 10,000 K blackbody with a small emitting area, probably originating in the hot spot where the accretion stream impacts the outer disk. However, one or more components in addition to the blackbody are needed to fit the FUV upturn and the red optical fluxes in the optical-UV spectrum. By comparing the mass accretion rate determined from the hot spot luminosity to the mean accretion rate inferred from the outburst history, we find that the latter is an order of magnitude smaller than the former, indicating that {approx}90% of the accreted mass must be lost from the system if the predictions of the disk instability model and the estimated interoutburst interval are correct. The mass accretion rate at the hot spot is 10{sup 5} the accretion rate at the black hole inferred from the X-ray luminosity. To reconcile these requires that outflows carry away virtually all of the accreted mass, a very low rate of mass transfer from the outer cold disk into the inner hot region, and/or radiatively inefficient accretion. We compared our broadband SED to two models of A0620-00 in quiescence: the advection-dominated accretion flow model and the maximally jet-dominated model. The comparison suggests that strong outflows may be present in the system, indicated by the discrepancies in accretion rates and the FUV upturn in flux in the SED.

  10. HUBBLE SPACE TELESCOPE FAR ULTRAVIOLET SPECTROSCOPY OF THE RECURRENT NOVA T PYXIDIS

    SciTech Connect (OSTI)

    Godon, Patrick; Sion, Edward M. [Astronomy and Astrophysics, Villanova University, Villanova, PA 19085 (United States); Starrfield, Sumner [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States); Livio, Mario; Williams, Robert E. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Woodward, Charles E. [Minnesota Institute for Astrophysics, University of Minnesota, Minneapolis, MN 55455 (United States); Kuin, Paul [Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT (United Kingdom); Page, Kim L., E-mail: patrick.godon@villanova.edu, E-mail: edward.sion@villanova.edu, E-mail: sumner.starrfield@asu.edu, E-mail: mlivio@stsci.edu, E-mail: wms@stsci.edu, E-mail: chelsea@astro.umn.edu, E-mail: n.kuin@ucl.ac.uk, E-mail: klp5@leicester.ac.uk [Department of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH (United Kingdom)

    2014-04-01

    With six recorded nova outbursts, the prototypical recurrent nova T Pyxidis (T Pyx) is the ideal cataclysmic variable system to assess the net change of the white dwarf mass within a nova cycle. Recent estimates of the mass ejected in the 2011 outburst ranged from a few ?10{sup –5} M {sub ?} to 3.3 × 10{sup –4} M {sub ?}, and assuming a mass accretion rate of 10{sup –8}-10{sup –7} M {sub ?} yr{sup –1} for 44 yr, it has been concluded that the white dwarf in T Pyx is actually losing mass. Using NLTE disk modeling spectra to fit our recently obtained Hubble Space Telescope COS and STIS spectra, we find a mass accretion rate of up to two orders of magnitude larger than previously estimated. Our larger mass accretion rate is due mainly to the newly derived distance of T Pyx (4.8 kpc, larger than the previous 3.5 kpc estimate), our derived reddening of E(B – V) = 0.35 (based on combined IUE and GALEX spectra), and NLTE disk modeling (compared to blackbody and raw flux estimates in earlier works). We find that for most values of the reddening (0.25 ? E(B – V) ? 0.50) and white dwarf mass (0.70 M {sub ?} ? M {sub wd} ? 1.35 M {sub ?}) the accreted mass is larger than the ejected mass. Only for a low reddening (?0.25 and smaller) combined with a large white dwarf mass (0.9 M {sub ?} and larger) is the ejected mass larger than the accreted one. However, the best results are obtained for a larger value of reddening.

  11. 13th TOPICAL CONFERENCE ON HIGH TEMPERATURE PLASMA DIAGNOSTICS SCIENTIFIC PROGRAM

    SciTech Connect (OSTI)

    C. BARNES

    2000-07-01

    Electron cyclotron emission (ECE) has been employed as a standard electron temperature profile diagnostic on many tokamaks and stellarators, but most magnetically confined plasma devices cannot take advantage of standard ECE diagnostics to measure temperature. They are either overdense, operating at high density relative to the magnetic field (e.g. {omega}{sub pe} >> {Omega}{sub ce} in a spherical torus) or they have insufficient density and temperature to reach the blackbody condition ({tau} > 2). Electron Bernstein waves (EBWs) are electrostatic waves which can propagate in overdense plasmas and have a high optical thickness at the electron cyclotron resonance layers, as a result of their large K{sub i}. This talk reports on measurements of EBW emission on the CDX-U spherical torus, where B{sub 0} {approx} 2 kG, {approx} 10{sup 13} cm{sup -3} and T{sub e} {approx} 10 - 200 eV. Results will be presented for both direct detection of EBWs and for mode-converted EBW emission. The EBW emission was absolutely calibrated and compared to the electron temperature profile measured by a multi-point Thomson scattering diagnostic. Depending on the plasma conditions, the mode-converted EBW radiation temperature was found to be {le} T{sub e} and the emission source was determined to be radially localized at the electron cyclotron resonance layer. A Langmuir triple probe was employed to measure changes in edge density profile in the vicinity of the upper hybrid resonance where the mode conversion of the EBWs is expected to occur. Changes in the mode conversion efficiency may explain the observation of mode-converted EBW radiation temperatures below T{sub e}. Initial results suggest EBW emission and EBW heating are viable concepts for plasmas where {omega}{sub pe} >> {Omega}{sub ce}.

  12. A COOL DUST FACTORY IN THE CRAB NEBULA: A HERSCHEL STUDY OF THE FILAMENTS

    SciTech Connect (OSTI)

    Gomez, H. L.; Clark, C. J. R.; Gomez, E. L.; Gear, W. K. [School of Physics and Astronomy, Cardiff University, The Parade, Cardiff CF24 3AA (United Kingdom); Krause, O.; Besel, M.-A.; Bouwman, J.; Henning, Th. [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Barlow, M. J.; Swinyard, B. M.; Owen, P. J.; Matsuura, M. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Rho, J. [SOFIA Science Center, Universities Space Research Association, NASA Ames Research Center, MS 232, Moffett Field, CA 94035 (United States); Ivison, R. J.; Sibthorpe, B. [UK Astronomy Technology Centre, Royal Observatory Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Polehampton, E. T. [Space Science and Technology Department, Rutherford Appleton Laboratory, Oxfordshire, OX11 0QX (United Kingdom)

    2012-11-20

    Whether supernovae are major sources of dust in galaxies is a long-standing debate. We present infrared and submillimeter photometry and spectroscopy from the Herschel Space Observatory of the Crab Nebula between 51 and 670 {mu}m as part of the Mass Loss from Evolved StarS program. We compare the emission detected with Herschel with multiwavelength data including millimeter, radio, mid-infrared, and archive optical images. We carefully remove the synchrotron component using the Herschel and Planck fluxes measured in the same epoch. The contribution from line emission is removed using Herschel spectroscopy combined with Infrared Space Observatory archive data. Several forbidden lines of carbon, oxygen, and nitrogen are detected where multiple velocity components are resolved, deduced to be from the nitrogen-depleted, carbon-rich ejecta. No spectral lines are detected in the SPIRE wavebands; in the PACS bands, the line contribution is 5% and 10% at 70 and 100 {mu}m and negligible at 160 {mu}m. After subtracting the synchrotron and line emission, the remaining far-infrared continuum can be fit with two dust components. Assuming standard interstellar silicates, the mass of the cooler component is 0.24{sup +0.32} {sub -0.08} M {sub Sun} for T = 28.1{sup +5.5} {sub -3.2} K. Amorphous carbon grains require 0.11 {+-} 0.01 M {sub Sun} of dust with T = 33.8{sup +2.3} {sub -1.8} K. A single temperature modified blackbody with 0.14 M {sub Sun} and 0.08 M {sub Sun} for silicate and carbon dust, respectively, provides an adequate fit to the far-infrared region of the spectral energy distribution but is a poor fit at 24-500 {mu}m. The Crab Nebula has condensed most of the relevant refractory elements into dust, suggesting the formation of dust in core-collapse supernova ejecta is efficient.

  13. EFFECT OF A HIGH OPACITY ON THE LIGHT CURVES OF RADIOACTIVELY POWERED TRANSIENTS FROM COMPACT OBJECT MERGERS

    SciTech Connect (OSTI)

    Barnes, Jennifer; Kasen, Daniel [Departments of Physics and Astronomy, 366 LeConte Hall, University of California, Berkeley, CA 94720 (United States)

    2013-09-20

    The coalescence of compact objects is a promising astrophysical source of detectable gravitational wave signals. The ejection of r-process material from such mergers may lead to a radioactively powered electromagnetic counterpart signal which, if discovered, would enhance the science returns. As very little is known about the optical properties of heavy r-process elements, previous light-curve models have adopted opacities similar to those of iron group elements. Here we consider the effect of heavier elements, particularly the lanthanides, which increase the ejecta opacity by several orders of magnitude. We include these higher opacities in time-dependent, multi-wavelength radiative transport calculations to predict the broadband light curves of one-dimensional models over a range of parameters (ejecta masses {approx}10{sup -3}-10{sup -1} M{sub Sun} and velocities {approx}0.1-0.3 c). We find that the higher opacities lead to much longer duration light curves which can last a week or more. The emission is shifted toward the infrared bands due to strong optical line blanketing, and the colors at later times are representative of a blackbody near the recombination temperature of the lanthanides (T {approx} 2500 K). We further consider the case in which a second mass outflow, composed of {sup 56}Ni, is ejected from a disk wind, and show that the net result is a distinctive two component spectral energy distribution, with a bright optical peak due to {sup 56}Ni and an infrared peak due to r-process ejecta. We briefly consider the prospects for detection and identification of these transients.

  14. The ultraviolet-bright, slowly declining transient PS1-11af as a partial tidal disruption event

    SciTech Connect (OSTI)

    Chornock, R.; Berger, E.; Zauderer, B. A.; Kamble, A.; Soderberg, A. M.; Czekala, I.; Dittmann, J.; Drout, M.; Foley, R. J.; Fong, W.; Kirshner, R. P.; Lunnan, R.; Marion, G. H.; Narayan, G. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Gezari, S. [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Rest, A.; Riess, A. G. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Chomiuk, L. [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Huber, M. E. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Lawrence, A., E-mail: rchornock@cfa.harvard.edu [Institute for Astronomy, University of Edinburgh Scottish Universities Physics Alliance, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); and others

    2014-01-01

    We present the Pan-STARRS1 discovery of the long-lived and blue transient PS1-11af, which was also detected by Galaxy Evolution Explorer with coordinated observations in the near-ultraviolet (NUV) band. PS1-11af is associated with the nucleus of an early type galaxy at redshift z = 0.4046 that exhibits no evidence for star formation or active galactic nucleus activity. Four epochs of spectroscopy reveal a pair of transient broad absorption features in the UV on otherwise featureless spectra. Despite the superficial similarity of these features to P-Cygni absorptions of supernovae (SNe), we conclude that PS1-11af is not consistent with the properties of known types of SNe. Blackbody fits to the spectral energy distribution are inconsistent with the cooling, expanding ejecta of a SN, and the velocities of the absorption features are too high to represent material in homologous expansion near a SN photosphere. However, the constant blue colors and slow evolution of the luminosity are similar to previous optically selected tidal disruption events (TDEs). The shape of the optical light curve is consistent with models for TDEs, but the minimum accreted mass necessary to power the observed luminosity is only ?0.002 M {sub ?}, which points to a partial disruption model. A full disruption model predicts higher bolometric luminosities, which would require most of the radiation to be emitted in a separate component at high energies where we lack observations. In addition, the observed temperature is lower than that predicted by pure accretion disk models for TDEs and requires reprocessing to a constant, lower temperature. Three deep non-detections in the radio with the Very Large Array over the first two years after the event set strict limits on the production of any relativistic outflow comparable to Swift J1644+57, even if off-axis.

  15. The Properties of Sub-mm Galaxies in Hierarchical Models

    E-Print Network [OSTI]

    Mark Swinbank; Cedric Lacey; Ian Smail; Carlton Baugh; Carlos Frenk; Andrew Blain; Scott Chapman; Kristen Coppin; Rob Ivison; Laura Hainline; Juan Gonzalez

    2008-09-11

    We use the combined GALFORM semi-analytical model of galaxy formation and GRASIL spectrophotometric code to investigate the properties of galaxies selected via their sub-mm emission. Our fiducial model has previously been shown to fit the properties of local ULIRGs, as well as the number counts of faint sub-mm galaxies. Here, we test the model in detail by comparing the SEDs and stellar, dynamical, gas and halo masses of sub-mm galaxies against observational data. We precisely mimic the sub-mm and radio selection function of the observations and show that the predicted far-infrared properties of model galaxies with S_850>5mJy and S_1.4>30uJy are in good agreement with observations. Although the dust emission model does not assume a single dust temperature, the far-infrared SEDs are well described by single component modified black-body spectrum with characteristic temperature 32+/-5K. We also find evidence that the observations may have uncovered evolution in the far-infrared--radio relation in ULIRGs out to z~2. We show that the predicted redshift distribution of sub-mm galaxies provides a reasonable fit to the observational data with a median redshift z=2.0, with the radio-selected subset predicted to make up approximately 75% of the population. However, the predicted K-band and mid-infrared (3--8um) flux densities of the sub-mm galaxies (and LBGs) are up to a factor 10x fainter than observed. This discrepancy may indicate that the stellar masses of the sub-mm galaxies in the model are too low: M~10^10Mo, while observations suggest more massive systems, M~10^11Mo. Finally, we discuss the potential modifications to the models which may improve the fit to the observational data. [Abridged

  16. Supernova Remnants in the AKARI IRC Survey of the Large Magellanic Cloud

    E-Print Network [OSTI]

    Ji Yeon Seok; Bon-Chul Koo; Takashi Onaka; Yoshifusa Ita; Ho-Gyu Lee; Jae-Joon Lee; Dae-Sik Moon; Itsuki Sakon; Hidehiro Kaneda; Hyung Mok Lee; Myung Gyoon Lee; Sung Eun Kim

    2008-11-10

    We present the near- to mid-infared study of supernova remnants (SNRs) using the AKARI IRC Survey of the Large Magellanic Cloud (LMC). The LMC survey observed about a 10 square degree area of the LMC in five bands centered at 3, 7, 11, 15, and 24 \\micron using the Infrared Camera (IRC) aboard AKARI. The number of SNRs in the survey area is 21, which is about a half of the known LMC SNRs. We systematically examined the AKARI images and identified eight SNRs with distinguishable infrared emission. All of them were detected at $\\gtrsim 10$ \\micron and some at 3 and 7 \\micron, too. We present their AKARI images and fluxes. In the 11/15 \\micron versus 15/24 \\micron color-color diagram, the SNRs appear to be aligned along a modified blackbody curve, representing thermal emission from dust at temperatures between 90 and 190 K. There is a good correlation between the 24 \\micron and X-ray fluxes of the SNRs. It was also found that there is a good correlation between the 24 \\micron and radio fluxes even if there is no direct physical connection between them. We considered the origin of the detected mid-infrared emission in individual SNRs. We conclude that the mid-infrared emissions in five SNRs that show morphologies similar to the X-rays are dominated by thermal emission from hot dust heated by X-ray emitting plasma. Their 15/24 \\micron color temperatures are generally higher than the Spitzer 24/70 \\micron color temperatures, which suggests that a single-temperature dust model cannot describe the full spectral energy distribution (SED) of the SNRs. It also implies that our understanding of the full SED is essential for estimating the dust destruction rate of grains by SNR shocks.

  17. The INTEGRAL long monitoring of persistent Ultra Compact X-ray Bursters

    E-Print Network [OSTI]

    M. Fiocchi; A. Bazzano; P. Ubertini; A. J. Bird; L. Natalucci; V. Sguera

    2008-10-10

    The combination of compact objects, short period variability and peculiar chemical composition of the Ultra Compact X-ray Binaries make up a very interesting laboratory to study accretion processes and thermonuclear burning on the neutron star surface. The improved large optical telescopes and more sensitive X-ray satellites have increased the number of known Ultra Compact X-ray Binaries allowing their study with unprecedented detail. We analyze the average properties common to all ultra compact Bursters observed by INTEGRAL from ~0.2keV to ~150keV. We have performed a systematic analysis of the INTEGRAL public data and Key-Program proprietary observations of a sample of the Ultra Compact X-ray Binaries. In order to study their average properties in a very broad energy band, we combined INTEGRAL with BeppoSAX and SWIFT data whenever possible. For sources not showing any significant flux variations along the INTEGRAL monitoring, we build the average spectrum by combining all available data; in the case of variable fluxes, we use simultaneous INTEGRAL and SWIFT observations when available. Otherwise we compared IBIS and PDS data to check the variability and combine BeppoSAX with INTEGRAL/IBIS data. All spectra are well represented by a two component model consisting of a disk-blackbody and Comptonised emission. The majority of these compact sources spend most of the time in a canonical low/hard state, with dominating Comptonised component and accretion rate lower than ~10^{-9}Msolar/yr, not depending on the used model to fit the data.

  18. A 0.8-2.4 ?m Transmission spectrum of the hot Jupiter CoRoT-1b

    SciTech Connect (OSTI)

    Schlawin, E.; Herter, T.; Zhao, M.; Teske, J. K.

    2014-03-01

    Hot Jupiters with brightness temperatures ?2000 K can have TiO and VO molecules as gaseous species in their atmospheres. The TiO and VO molecules can potentially induce temperature inversions in hot Jupiter atmospheres and also have an observable signature of large optical to infrared transit depth ratios. Previous transmission spectra of very hot Jupiters have shown a lack of TiO and VO, but only in planets that also appear to lack temperature inversions. We measure the transmission spectrum of CoRoT-1b, a hot Jupiter that was predicted to have a temperature inversion potentially due to significant TiO and VO in its atmosphere. We employ the multi-object spectroscopy method using the SpeX and MORIS instruments on the Infrared Telescope Facility (IRTF) and the Gaussian process method to model red noise. By using a simultaneous reference star on the slit for calibration and a wide slit to minimize slit losses, we achieve transit depth precision of 0.03%-0.09%, comparable to the atmospheric scale height but detect no statistically significant molecular features. We combine our IRTF data with optical CoRoT transmission measurements to search for differences in the optical and near-infrared absorption that would arise from TiO/VO. Our IRTF spectrum and the CoRoT photometry disfavor a TiO/VO-rich spectrum for CoRoT-1b, suggesting that the atmosphere has another absorber that could create a temperature inversion or that the blackbody-like emission from the planet is due to a spectroscopically flat cloud, dust, or haze layer that smoothes out molecular features in both CoRoT-1b's emission and transmission spectra. This system represents the faintest planet hosting star (K = 12.2) with a measured planetary transmission spectrum.

  19. SWIFT DISCOVERY OF A NEW SOFT GAMMA REPEATER, SGR J1745-29, NEAR SAGITTARIUS A*

    SciTech Connect (OSTI)

    Kennea, J. A.; Burrows, D. N.; Kouveliotou, C.; Goegues, E.; Kaneko, Y.; Evans, P. A.; Degenaar, N.; Reynolds, M. T.; Miller, J. M.; Wijnands, R.; Mori, K.; Gehrels, N.

    2013-06-20

    Starting in 2013 February, Swift has been performing short daily monitoring observations of the G2 gas cloud near Sgr A* with the X-Ray Telescope to determine whether the cloud interaction leads to an increase in the flux from the Galactic center. On 2013 April 24 Swift detected an order of magnitude rise in the X-ray flux from the region near Sgr A*. Initially thought to be a flare from Sgr A*, the detection of a short hard X-ray burst from the same region by the Burst Alert Telescope suggested that the flare was from an unresolved new Soft Gamma Repeater, SGR J1745-29. Here we present the discovery of SGR J1745-29 by Swift, including analysis of data before, during, and after the burst. We find that the spectrum in the 0.3-10 keV range is well fit by an absorbed blackbody model with kT{sub BB} {approx_equal} 1 keV and absorption consistent with previously measured values from the quiescent emission from Sgr A*, strongly suggesting that this source is at a similar distance. Only one SGR burst has been detected so far from the new source, and the persistent light curve shows little evidence of decay in approximately two weeks of monitoring after outburst. We discuss this light curve trend and compare it with those of other well covered SGR outbursts. We suggest that SGR J1745-29 belongs to an emerging subclass of magnetars characterized by low burst rates and prolonged steady X-ray emission one to two weeks after outburst onset.

  20. Ultraviolet observations of Super-Chandrasekhar mass type Ia supernova candidates with swift UVOT

    SciTech Connect (OSTI)

    Brown, Peter J.; Smitka, Michael T.; Krisciunas, Kevin; Wang, Lifan [George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A and M University, Department of Physics and Astronomy, 4242 TAMU, College Station, TX 77843 (United States); Kuin, Paul; De Pasquale, Massimiliano [Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking Surrey, RH5 6NT (United Kingdom); Scalzo, Richard [Research School of Astronomy and Astrophysics, The Australian National University, Mount Stromlo Observatory, Cotter Road, Weston Creek, ACT 2611 (Australia); Holland, Stephen [Space Telescope Science Center 3700 San Martin Drive, Baltimore, MD 21218 (United States); Milne, Peter, E-mail: pbrown@physics.tamu.edu [Steward Observatory, University of Arizona, Tucson, AZ 85719 (United States)

    2014-05-20

    Among Type Ia supernovae (SNe Ia), a class of overluminous objects exist whose ejecta mass is inferred to be larger than the canonical Chandrasekhar mass. We present and discuss the UV/optical photometric light curves, colors, absolute magnitudes, and spectra of three candidate Super-Chandrasekhar mass SNe—2009dc, 2011aa, and 2012dn—observed with the Swift Ultraviolet/Optical Telescope. The light curves are at the broad end for SNe Ia, with the light curves of SN 2011aa being among the broadest ever observed. We find all three to have very blue colors which may provide a means of excluding these overluminous SNe from cosmological analysis, though there is some overlap with the bluest of 'normal' SNe Ia. All three are overluminous in their UV absolute magnitudes compared to normal and broad SNe Ia, but SNe 2011aa and 2012dn are not optically overluminous compared to normal SNe Ia. The integrated luminosity curves of SNe 2011aa and 2012dn in the UVOT range (1600-6000 Å) are only half as bright as SN 2009dc, implying a smaller {sup 56}Ni yield. While it is not enough to strongly affect the bolometric flux, the early time mid-UV flux makes a significant contribution at early times. The strong spectral features in the mid-UV spectra of SNe 2009dc and 2012dn suggest a higher temperature and lower opacity to be the cause of the UV excess rather than a hot, smooth blackbody from shock interaction. Further work is needed to determine the ejecta and {sup 56}Ni masses of SNe 2011aa and 2012dn and to fully explain their high UV luminosities.

  1. Superluminous supernovae as standardizable candles and high-redshift distance probes

    SciTech Connect (OSTI)

    Inserra, C.; Smartt, S. J., E-mail: c.inserra@qub.ac.uk [Astrophysics Research Centre, School of Mathematics and Physics, Queens University Belfast, Belfast BT7 1NN (United Kingdom)

    2014-12-01

    We investigate the use of type Ic superluminous supernovae (SLSN Ic) as standardizable candles and distance indicators. Their appeal as cosmological probes stems from their remarkable peak luminosities, hot blackbody temperatures, and bright rest-frame ultraviolet emission. We present a sample of 16 published SLSN, from redshifts 0.1 to 1.2, and calculate accurate K corrections to determine uniform magnitudes in 2 synthetic rest-frame filter bandpasses with central wavelengths at 400 nm and 520 nm. At 400 nm, we find an encouragingly low scatter in their uncorrected, raw mean magnitudes with M(400) = –21.86 ± 0.35 mag for the full sample of 16 objects. We investigate the correlation between their decline rates and peak magnitude and find that the brighter events appear to decline more slowly. In a manner similar to the Phillips relation for type Ia SNe (SNe Ia), we define a ?M {sub 20} decline relation. This correlates peak magnitude and decline over 20 days and can reduce the scatter in standardized peak magnitudes to ±0.22 mag. We further show that M(400) appears to have a strong color dependence. Redder objects are fainter and also become redder faster. Using this peak magnitudecolor evolution relation, a surprisingly low scatter of between ±0.08 mag and ±0.13 mag can be found in peak magnitudes, depending on sample selection. However, we caution that only 8 to 10 objects currently have enough data to test this peak magnitudecolor evolution relation. We conclude that SLSN Ic are promising distance indicators in the high-redshift universe in regimes beyond those possible with SNe Ia. Although the empirical relationships are encouraging, the unknown progenitor systems, how they may evolve with redshift, and the uncertain explosion physics are of some concern. The two major measurement uncertainties are the limited numbers of low-redshift, well-studied objects available to test these relationships and internal dust extinction in the host galaxies.

  2. Photosphere emission in the X-ray flares of swift gamma-ray bursts and implications for the fireball properties

    SciTech Connect (OSTI)

    Peng, Fang-Kun; Liang, En-Wei; Xi, Shao-Qiang; Lu, Rui-Jing; Zhang, Bing [Guangxi Key Laboratory for Relativistic Astrophysics, the Department of Physics, Guangxi University, Nanning 530004 (China); Wang, Xiang-Yu [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China); Hou, Shu-Jin [Institute of Physics and Electronic Engineering, Nanyang Normal College, Nanyang 473061 (China); Zhang, Jin, E-mail: lew@gxu.edu.cn, E-mail: xywang@nju.edu.cn, E-mail: zhang@physics.unlv.edu [National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

    2014-11-10

    X-ray flares of gamma-ray bursts (GRBs) are usually observed in the soft X-ray range and the spectral coverage is limited. In this paper, we present an analysis of 32 GRB X-ray flares that are simultaneously observed by both Burst Alert Telescope and X-Ray Telescope on board the Swift mission, so that a joint spectral analysis with a wider spectral coverage is possible. Our results show that the joint spectra of 19 flares are fitted with the absorbed single power law or the Band function models. More interestingly, the joint spectra of the other 13 X-ray flares are fitted with the absorbed single power-law model plus a blackbody component. Phenomenally, the observed spectra of these 13 flares are analogous to several GRBs with a thermal component, but only with a much lower temperature of kT = 1 ? 3 keV. Assuming that the thermal emission is the photosphere emission of the GRB fireball, we derive the fireball properties of the 13 flares that have redshift measurements, such as the bulk Lorentz factor ?{sub ph} of the outflow. The derived ?{sub ph} range from 50 to 150 and a relation of ?{sub ph} to the thermal emission luminosity is found. It is consistent with the ?{sub 0} – L {sub iso} relations that are derived for the prompt gamma-ray emission. We discuss the physical implications of these results within the content of jet composition and the radiation mechanism of GRBs and X-ray flares.

  3. Low energy spectral index and E{sub p} evolution of quasi-thermal photosphere emission of gamma-ray bursts

    SciTech Connect (OSTI)

    Deng, Wei; Zhang, Bing, E-mail: deng@physics.unlv.edu, E-mail: zhang@physics.unlv.edu [Department of Physics and Astronomy, University of Nevada Las Vegas, Las Vegas, NV 89154 (United States)

    2014-04-20

    Recent observations by the Fermi satellite suggest that a photosphere emission component is contributing to the observed spectrum of many gamma-ray bursts (GRBs). One important question is whether the photosphere component can interpret the typical 'Band' function of GRBs with a typical low energy photon spectral index ? ? –1. We perform a detailed study of the photosphere emission spectrum by progressively introducing several physical ingredients previously not fully incorporated, including the probability distribution of the location of a dynamically evolving photosphere, superposition of emission from an equal arrival time 'volume' in a continuous wind, the evolution of optical depth of a wind with finite but evolving outer boundary, as well as the effect of different top-hat wind luminosity (L{sub w} ) profiles. By assuming a comoving blackbody spectrum emerging from the photosphere, we find that for an outflow with a constant or increasing L{sub w} , the low-energy spectrum below the peak energy (E{sub p} ), can be modified to F {sub ?} ? ?{sup 1.5} (? ? +0.5). A softer (–1 < ? < +0.5) or flat (? = –1) spectrum can be obtained during the L{sub w} decreasing phase or high-latitude-emission-dominated phase. We also study the evolution of E{sub p} as a function of wind and photosphere luminosity in this photosphere model. An E{sub p} – L tracking pattern can be reproduced if a certain positive dependence between the dimensionless entropy ? and L{sub w} is introduced. However, the hard-to-soft evolution pattern cannot be reproduced unless a contrived condition is invoked. In order to interpret the Band spectrum, a more complicated photosphere model or a different energy dissipation and radiation mechanism is needed.

  4. SGR J1550-5418 BURSTS DETECTED WITH THE FERMI GAMMA-RAY BURST MONITOR DURING ITS MOST PROLIFIC ACTIVITY

    SciTech Connect (OSTI)

    Van der Horst, A. J.; Finger, M. H. [Universities Space Research Association, NSSTC, Huntsville, AL 35805 (United States); Kouveliotou, C. [Space Science Office, VP62, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States); Gorgone, N. M. [Connecticut College, New London, CT 06320 (United States); Kaneko, Y.; Goegues, E.; Lin, L. [Sabanc Latin-Small-Letter-Dotless-I University, Orhanl Latin-Small-Letter-Dotless-I -Tuzla, Istanbul 34956 (Turkey); Baring, M. G. [Department of Physics and Astronomy, Rice University, MS-108, P.O. Box 1892, Houston, TX 77251 (United States); Guiriec, S.; Bhat, P. N.; Chaplin, V. L.; Goldstein, A. [University of Alabama, Huntsville, CSPAR, Huntsville, AL 35805 (United States); Granot, J. [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Watts, A. L. [Astronomical Institute 'Anton Pannekoek', University of Amsterdam, Postbus 94249, 1090 GE Amsterdam (Netherlands); Bissaldi, E.; Gruber, D. [Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, Postfach 1312, 85748 Garching (Germany); Gehrels, N.; Harding, A. K. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Gibby, M. H.; Giles, M. M., E-mail: A.J.VanDerHorst@uva.nl [Jacobs Technology, Inc., Huntsville, AL (United States); and others

    2012-04-20

    We have performed detailed temporal and time-integrated spectral analysis of 286 bursts from SGR J1550-5418 detected with the Fermi Gamma-ray Burst Monitor (GBM) in 2009 January, resulting in the largest uniform sample of temporal and spectral properties of SGR J1550-5418 bursts. We have used the combination of broadband and high time-resolution data provided with GBM to perform statistical studies for the source properties. We determine the durations, emission times, duty cycles, and rise times for all bursts, and find that they are typical of SGR bursts. We explore various models in our spectral analysis, and conclude that the spectra of SGR J1550-5418 bursts in the 8-200 keV band are equally well described by optically thin thermal bremsstrahlung (OTTB), a power law (PL) with an exponential cutoff (Comptonized model), and two blackbody (BB) functions (BB+BB). In the spectral fits with the Comptonized model, we find a mean PL index of -0.92, close to the OTTB index of -1. We show that there is an anti-correlation between the Comptonized E{sub peak} and the burst fluence and average flux. For the BB+BB fits, we find that the fluences and emission areas of the two BB functions are correlated. The low-temperature BB has an emission area comparable to the neutron star surface area, independent of the temperature, while the high-temperature BB has a much smaller area and shows an anti-correlation between emission area and temperature. We compare the properties of these bursts with bursts observed from other SGR sources during extreme activations, and discuss the implications of our results in the context of magnetar burst models.

  5. A LINGERING NON-THERMAL COMPONENT IN THE GAMMA-RAY BURST PROMPT EMISSION: PREDICTING GeV EMISSION FROM THE MeV SPECTRUM

    SciTech Connect (OSTI)

    Basak, Rupal; Rao, A. R., E-mail: rupalb@tifr.res.in, E-mail: arrao@tifr.res.in [Tata Institute of Fundamental Research, Mumbai 400005 (India)

    2013-09-20

    The high-energy GeV emission of gamma-ray bursts (GRBs) detected by Fermi/LAT has a significantly different morphology compared to the lower energy MeV emission detected by Fermi/GBM. Though the late-time GeV emission is believed to be synchrotron radiation produced via an external shock, this emission as early as the prompt phase is puzzling. A meaningful connection between these two emissions can be drawn only by an accurate description of the prompt MeV spectrum. We perform a time-resolved spectroscopy of the Gamma-ray Burst Monitor (GBM) data of long GRBs with significant GeV emission, using a model consisting of two blackbodies and a power law. We examine in detail the evolution of the spectral components and find that GRBs with high GeV emission (GRB 090902B and GRB 090926A) have a delayed onset of the power-law component in the GBM spectrum, which lingers at the later part of the prompt emission. This behavior mimics the flux evolution in the Large Area Telescope (LAT). In contrast, bright GBM GRBs with an order of magnitude lower GeV emission (GRB 100724B and GRB 091003) show a coupled variability of the total and the power-law flux. Further, by analyzing the data for a set of 17 GRBs, we find a strong correlation between the power-law fluence in the MeV and the LAT fluence (Pearson correlation: r = 0.88 and Spearman correlation: ? = 0.81). We demonstrate that this correlation is not influenced by the correlation between the total and the power-law fluences at a confidence level of 2.3?. We speculate the possible radiation mechanisms responsible for the correlation.

  6. Hot electromagnetic outflows. III. Displaced fireball in a strong magnetic field

    SciTech Connect (OSTI)

    Thompson, Christopher; Gill, Ramandeep [Canadian Institute for Theoretical Astrophysics, 60 St. George Street, Toronto, ON M5S 3H8 (Canada)

    2014-08-10

    The evolution of a dilute electron-positron fireball is calculated in the regime of strong magnetization and high compactness (? ? 10{sup 3}-10{sup 8}). Heating is applied at a low effective temperature (<25 keV), appropriate to breakout from a confining medium, so that relaxation to a blackbody is inhibited by pair annihilation. The diffusion equation for Compton scattering by thermal pairs is coupled to a trans-relativistic cyclo-synchrotron source. We find that the photon spectrum develops a quasi-thermal peak at energy ?0.1 m{sub e}c {sup 2} in the comoving frame, with a power-law slope below it that is characteristic of gamma-ray bursts (GRBs; F{sub ?} ? const). The formation of a thermal high-energy spectrum is checked using the full kinetic equations. Calculations for a baryon-dominated photosphere reveal a lower spectral peak energy, and a harder low-energy spectrum, unless ion rest mass carries ? 10{sup –5} of the energy flux. We infer that (1) the GRB spectrum is inconsistent with the neutron-rich wind emitted by a young magnetar or neutron torus, and points to an event horizon in the engine; (2) neutrons play a negligible role in prompt gamma-ray emission; (3) the relation between observed peak frequency and burst energy is bounded below by the observed Amati relation if the Lorentz factor ?(opening angle){sup –1} at breakout, and the jet is surrounded by a broader sheath that interacts with a collapsing stellar core; (4) X-ray flashes are consistent with magnetized jets with ion-dominated photospheres; (5) high-frequency Alfvén waves may become charge starved in the dilute pair gas; (6) limitations on magnetic reconnection from plasma collisionality have been overestimated.

  7. The continued optical to mid-infrared evolution of V838 Monocerotis

    SciTech Connect (OSTI)

    Loebman, S. R.; Wisniewski, J. P.; Schmidt, S. J.; Kowalski, A. F.; Barry, R. K.; Bjorkman, K. S.; Hammel, H. B.; Hawley, S. L.; Szkody, P.; Hebb, L.; Kasliwal, M. M.; Lynch, D. K.; Russell, R. W.; Sitko, M. L.

    2015-01-01

    The eruptive variable V838 Monocerotis (V838 Mon) gained notoriety in 2002 when it brightened nine magnitudes in a series of three outbursts and then rapidly evolved into an extremely cool supergiant. We present optical, near-infrared (near-IR), and mid-IR spectroscopic and photometric observations of V838 Mon obtained between 2008 and 2012 at the Apache Point Observatory 3.5 m, NASA IRTF 3 m, and Gemini South 8 m telescopes. We contemporaneously analyze the optical and IR spectroscopic properties of V838 Mon to arrive at a revised spectral type L3 supergiant and effective temperature T{sub eff}?2000–2200 K. Because there are no existing optical observational data for L supergiants, we speculate that V838 Mon may represent the prototype for L supergiants in this wavelength regime. We find a low level of H? emission present in the system, consistent with interaction between V838 Mon and its B3V binary; however, we cannot rule out a stellar collision as the genesis event, which could result in the observed H? activity. Based upon a two-component blackbody fit to all wavelengths of our data, we conclude that, as of 2009, a shell of ejecta surrounded V838 Mon at a radius of R=263±10 AU with a temperature of T=285±2 K. This result is consistent with IR interferometric observations from the same era and predictions from the Lynch et al. model of the expanding system, which provides a simple framework for understanding this complicated system.

  8. The formation of massive primordial stars in the presence of moderate UV backgrounds

    SciTech Connect (OSTI)

    Latif, M. A.; Schleicher, D. R. G.; Bovino, S. [Institut für Astrophysik, Georg-August-Universität, Friedrich-Hund-Platz 1, D-37077 Göttingen (Germany); Grassi, T. [Centre for Star and Planet Formation, Natural History Museum of Denmark, Øster Voldgade 5-7, DK-1350 Copenhagen (Denmark); Spaans, M., E-mail: mlatif@astro.physik.uni-goettingen.de [Kapteyn Astronomical Institute, University of Groningen, 9700-AV Groningen (Netherlands)

    2014-09-01

    Radiative feedback produced by stellar populations played a vital role in early structure formation. In particular, photons below the Lyman limit can escape the star-forming regions and produce a background ultraviolet (UV) flux, which consequently may influence the pristine halos far away from the radiation sources. These photons can quench the formation of molecular hydrogen by photodetachment of H{sup –}. In this study, we explore the impact of such UV radiation on fragmentation in massive primordial halos of a few times 10{sup 7} M {sub ?}. To accomplish this goal, we perform high resolution cosmological simulations for two distinct halos and vary the strength of the impinging background UV field in units of J {sub 21} assuming a blackbody radiation spectrum with a characteristic temperature of T {sub rad} = 10{sup 4} K. We further make use of sink particles to follow the evolution for 10,000 yr after reaching the maximum refinement level. No vigorous fragmentation is observed in UV-illuminated halos while the accretion rate changes according to the thermal properties. Our findings show that a few 10{sup 2}-10{sup 4} solar mass protostars are formed when halos are irradiated by J {sub 21} = 10-500 at z > 10 and suggest a strong relation between the strength of the UV flux and mass of a protostar. This mode of star formation is quite different from minihalos, as higher accretion rates of about 0.01-0.1 M {sub ?} yr{sup –1} are observed by the end of our simulations. The resulting massive stars are potential cradles for the formation of intermediate-mass black holes at earlier cosmic times and contribute to the formation of a global X-ray background.

  9. Structure of pair winds from compact objects with application to emission from hot bare strange stars

    E-Print Network [OSTI]

    A. G. Aksenov; M. Milgrom; V. V. Usov

    2004-03-15

    We consider a stationary, spherically outflowing wind consisting of electron-positron pairs and photons. We do not assume thermal equilibrium, and include the two-body processes that occur in such a wind: Moller and Bhaba scattering of pairs, Compton scattering, two-photon pair annihilation, and two-photon pair production, together with their radiative three-body variants: bremsstrahlung, double Compton scattering, and three-photon pair annihilation, with their inverse processes. In the concrete example described here, the wind injection source is a hot, bare, strange star. Such stars are thought to be powerful sources of pairs created by the Coulomb barrier at the quark surface. We present a new, finite-difference scheme for solving the relativistic kinetic Boltzmann equations for pairs and photons. Using this method we study the kinetics of the wind particles and the emerging emission for total luminosities of L=10^{34}-10^{42} ergs/s. We find the rates of particle number and energy outflows, outflow velocities, number densities, energy spectra, and other parameters for both photons and pairs as functions of the distance. We find that for L>2x10^{35} ergs/s, photons dominate the emerging emission. As L increases from ~ 10^{34} to 10^{42} ergs/s, the mean energy of emergent photons decreases from ~400-500 keV to 40 keV, as the spectrum changes in shape from that of a wide annihilation line to nearly a blackbody spectrum with a high energy (> 100 keV) tail. These results are pertinent to the deduction of the outside appearance of hot bare strange stars, which might help discern them from neutron stars.

  10. Environmental assessment for the satellite power system concept development and evaluation program-electromagnetic systems compatibility

    SciTech Connect (OSTI)

    Davis, K A; Grant, W B; Morrison, E L; Juroshek, J R

    1981-01-01

    The EMC analysis addressed only the direct effects of electromagnetic emissions from the SPS on other technological systems. Emissions were defined quite broadly, including not only those from the microwave system, but also thermal blackbody emission and scattered sunlight from the satellite. The analysis is based on the design for an SPS as described in the Reference System Report and some quantitative conclusions, e.g., ranges from rectenna sites at which effects are expected are specific to that design. The methodology and qualitative conclusions, however, apply to an SPS concept using microwave power transmission. Quantitative conclusions have been obtained parametrically and can be adjusted as SPS designs change. The electromagnetic environment that the Reference System would produce, and in which other systems would have to function, is described. As an early part of the EMC Assessment, the problems expected for a hypothetical rectenna site, in the Mojave Desert of southern California, were analyzed in detail. This effort provided an initial quantitative indication of the scope of potential EMC problems and indicated the importance of EMC considerations in rectenna site selection. The results of this analysis are presented. The effects of SPS microwave emissions on important categories of electronic systems and equipment are summarized, with many examples of test results and demonstrated techniques for mitigation of problems encountered. SPS effects on other satellite systems are presented. Astronomical research frequently involves measurement of extremely low levels of electromagnetic radiation and is thus very susceptible to interference. The concerns of both radio astronomy with microwave emissions from SPS and optical astronomy with sunlight scattered from SPS spacecraft are discussed. Summaries of mitigation techniques, cost estimates, and conclusions are presented. (WHK)

  11. The XMM-Newton view of radio-quiet and X-ray dim isolated neutron stars

    E-Print Network [OSTI]

    F. Haberl

    2004-01-07

    (shortened) As part of the guaranteed time, guest observer and calibration programs, XMM-Newton extensively observed a group of six thermally emitting, isolated neutron stars which are neither connected with a supernova remnant nor show pulsed radio emission. Four of the six sources are now well established as X-ray pulsars: The 11.37 s period of RX J0806.4-4123 was confirmed in a second XMM-Newton observation. In the case of the X-ray faintest of the six stars, RX J0420.0-5022, the period marginally indicated in ROSAT data was not seen in the EPIC data, instead a 3.45 s pulse period was clearly detected. Spectral variations with pulse phase were discovered for the known 8.39 s pulsar RX J0720.4-3125 and also RBS1223. For the latter EPIC data revealed a double-peaked pulse profile for a neutron star spin period of 10.31 s. The X-ray continuum spectra of all six objects are consistent with a Planckian energy distribution with black-body temperatures kT between 40 eV and 100 eV. EPIC data of the pulsars RBS1223 and RX J0720.4-3125 revealed a broad absorption feature in their spectra at energies of 100-300 eV and ~260 eV, respectively. The depth of this feature varies with pulse phase and may be caused by cyclotron resonance scattering of protons or heavy ions in a strong magnetic field. In such a picture the inferred field strength exceeds 10^13 Gauss, in the case of RX J0720.4-3125 consistent with the value estimated from its pulse period derivative. A similar absorption feature in the RGS and EPIC spectra of RX J1605.3+3249 was reported recently.

  12. Probing correlations of early magnetic fields using ?-distortion

    SciTech Connect (OSTI)

    Ganc, Jonathan; Sloth, Martin S. E-mail: sloth@cp3.dias.sdu.dk

    2014-08-01

    The damping of a non-uniform magnetic field between the redshifts of about 10{sup 4} and 10{sup 6} injects energy into the photon-baryon plasma and causes the CMB to deviate from a perfect blackbody spectrum, producing a so-called ?-distortion. We can calculate the correlation (? T) of this distortion with the temperature anisotropy T of the CMB to search for a correlation ( B{sup 2}?) between the magnetic field B and the curvature perturbation ?; knowing the ( B{sup 2}?) correlation would help us distinguish between different models of magnetogenesis. Since the perturbations which produce the ?-distortion will be much smaller scale than the relevant density perturbations, the observation of this correlation is sensitive to the squeezed limit of ( B{sup 2}?), which is naturally parameterized by b{sub NL} (a parameter defined analogously to f{sub NL}). We find that a PIXIE-like CMB experiments has a signal to noise S/N? 1.0 × b{sub NL} ( B-tilde {sub ?}/10nG){sup 2}, where B-tilde {sub ?} is the magnetic field's strength on ?-distortion scales normalized to today's redshift; thus, a 10 nG field would be detectable with b{sub NL}=O(1). However, if the field is of inflationary origin, we generically expect it to be accompanied by a curvature bispectrum (?{sup 3}) induced by the magnetic field. For sufficiently small magnetic fields, the signal ( B{sup 2} ?) will dominate, but for B-tilde {sub ?}?> 1 nG, one would have to consider the specifics of the inflationary magnetogenesis model. We also discuss the potential post-magnetogenesis sources of a ( B{sup 2}?) correlation and explain why there will be no contribution from the evolution of the magnetic field in response to the curvature perturbation.

  13. Quantum logic with molecular ions

    E-Print Network [OSTI]

    Fabian Wolf; Yong Wan; Jan C. Heip; Florian Gebert; Chunyan Shi; Piet O. Schmidt

    2015-07-27

    Laser spectroscopy of cold and trapped molecular ions is a powerful tool for fundamental physics, including the determination of fundamental constants, the laboratory test for their possible variation, and the search for a possible electric dipole moment of the electron. Optical clocks based on molecular ions sensitive to some of these effects are expected to achieve uncertainties approaching the $10^{-18}$ level. While the complexity of molecular structure facilitates these applications, the absence of cycling transitions poses a challenge for direct laser cooling, quantum state control, and detection. Previously employed state detection techniques based on photo-dissociation or chemical reactions are destructive and therefore inefficient. Here we experimentally demonstrate non-destructive state detection of a single trapped molecular ion through its strong Coulomb coupling to a well-controlled co-trapped atomic ion. An algorithm based on a state-dependent optical dipole force(ODF) changes the internal state of the atom conditioned on the internal state of the molecule. We show that individual states in the molecule can be distinguished by their coupling strength to the ODF and observe black-body radiation-induced quantum jumps between rotational states. Using the detuning dependence of the state detection signal, we implement a variant of quantum logic spectroscopy and improve upon a previous measurement of the $\\mathrm{X}^1\\Sigma^+(J=1)\\rightarrow\\mathrm{A}^1\\Sigma^+(J=0)$ transition in MgH, finding a frequency of 1067.74752(53)THz. We estimate that non-destructive state detection with near 100% efficiency could take less than 10 ms. The technique we demonstrate is applicable to a wide range of molecular ions, enabling further applications in state-controlled quantum chemistry and spectroscopic investigations of molecules serving as probes for interstellar clouds.

  14. EVOLUTION OF X-RAY SPECTRA AND LIGHT CURVES OF V1494 AQUILAE

    SciTech Connect (OSTI)

    Rohrbach, J. G.; Ness, J.-U.; Starrfield, S. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287-1404 (United States)], E-mail: Jonathan.Rohrbach@asu.edu, E-mail: Jan-Uwe.Ness@asu.edu, E-mail: Sumner.Starrfield@asu.edu, E-mail: juness@sciops.esa.int

    2009-06-15

    We present six Chandra X-ray spectra and light curves obtained for the nova V1494 Aql (1999 No. 2) in outburst. The first three observations were taken with the Advanced CCD Imaging Spectrometer (ACIS-I) on days 134, 187, and 248 after outburst. The count rates were 1.00, 0.69, and 0.53 counts s{sup -1}, respectively. We found no significant periodicity in the ACIS light curves. The X-ray spectra show continuum emission and lines originating from N and O. We found acceptable spectral fits using isothermal APEC models with significantly increased elemental abundances of O and N for all observations. On day 248 after outburst a bright soft component appeared in addition to the fading emission lines. The Chandra observations on days 300, 304, and 727 were carried out with the High Resolution Camera/Low Energy Transmission Grating Spectrometer (LETGS). The spectra consist of continuum emission plus strong emission lines of O and N, implying a high abundance of these elements. On day 300, a flare occurred and periodic oscillations were detected in the light curves taken on days 300 and 304. This flare must have originated deep in the outflowing material since it was variable on short timescales. The spectra extracted immediately before and after the flare are remarkably similar, implying that the flare was an extremely isolated event. Our attempts to fit blackbody, cloudy, or APEC models to the LETGS spectra failed, owing to the difficulty in disentangling continuum and emission-line components. The spectrum extracted during the flare shows a significant increase in the strengths of many of the lines and the appearance of several previously undetected lines. In addition, some of the lines seen before and after the flare are not present during the flare. On day 727 only the count rate from the zeroth order could be derived, and the source was too faint for the extraction of a light curve or spectrum.

  15. Discovery of slow X-ray pulsations in the high-mass X-ray binary 4U 2206+54

    E-Print Network [OSTI]

    P. Reig; J. M Torrejon; I. Negueruela; P. Blay; M. Ribo; J. Wilms

    2008-12-12

    The source 4U 2206+54 is one of the most enigmatic high-mass X-ray binaries. In spite of intensive searches, X-ray pulsations have not been detected in the time range 0.001-1000 s. A cyclotron line at ~30 keV has been suggested by various authors but never detected with significance. The stellar wind of the optical companion is abnormally slow. The orbital period, initially reported to be 9.6 days, disappeared and a new periodicity of 19.25 days emerged. Our new long and uninterrupted RXTE observations allow us to search for long (~1 hr) pulsations for the first time. We have discovered 5560-s pulsations in the light curve of 4U 2206+54. Initially detected in RXTE data, these pulsations are also present in INTEGRAL and EXOSAT observations. The average X-ray luminosity in the energy range 2-10 keV is 1.5 x 10^{35} erg s^{-1} with a ratio Fmax/Fmin ~ 5. This ratio implies an eccentricity of ~0.4, somewhat higher than previously suggested. The source also shows a soft excess at low energies. If the soft excess is modelled with a blackbody component, then the size and temperature of the emitting region agrees with its interpretation in terms of a hot spot on the neutron star surface. The source displays variability on time scales of days, presumably due to changes in the mass accretion rate as the neutron star moves around the optical companion in a moderately eccentric orbit.

  16. DUST AROUND R CORONAE BOREALIS STARS. II. INFRARED EMISSION FEATURES IN AN H-POOR ENVIRONMENT

    SciTech Connect (OSTI)

    Garcia-Hernandez, D. A. [Instituto de Astrofisica de Canarias, C/Via Lactea s/n, E-38200 La Laguna (Spain); Rao, N. Kameswara [543, 17th Main, IV Sector, HSR Layout, Bangalore 560102 and Indian Institute of Astrophysics, Bangalore 560034 (India); Lambert, D. L., E-mail: agarcia@iac.es, E-mail: nkrao@iiap.res.in, E-mail: dll@astro.as.utexas.edu [W. J. McDonald Observatory, University of Texas at Austin, 1 University Station, C1400, Austin, TX 78712-0259 (United States)

    2013-08-20

    Residual Spitzer/Infrared Spectrograph spectra for a sample of 31 R Coronae Borealis (RCB) stars are presented and discussed in terms of narrow emission features superimposed on the quasi-blackbody continuous infrared emission. A broad {approx}6-10 {mu}m dust emission complex is seen in the RCBs showing an extreme H-deficiency. A secondary and much weaker {approx}11.5-15 {mu}m broad emission feature is detected in a few RCBs with the strongest {approx}6-10 {mu}m dust complex. The Spitzer infrared spectra reveal for the first time the structure within the {approx}6-10 {mu}m dust complex, showing the presence of strong C-C stretching modes at {approx}6.3 and 8.1 {mu}m as well as of other dust features at {approx}5.9, 6.9, and 7.3 {mu}m, which are attributable to amorphous carbonaceous solids with little or no hydrogen. The few RCBs with only moderate H-deficiencies display the classical ''unidentified infrared bands (UIRs)'' and mid-infrared features from fullerene-related molecules. In general, the characteristics of the RCB infrared emission features are not correlated with the stellar and circumstellar properties, suggesting that the RCB dust features may not be dependent on the present physical conditions around RCB stars. The only exception seems to be the central wavelength of the 6.3 {mu}m feature, which is blueshifted in those RCBs showing also the UIRs, i.e., the RCBs with the smallest H deficiency.

  17. HERSCHEL-RESOLVED OUTER BELTS OF TWO-BELT DEBRIS DISKS AROUND A-TYPE STARS: HD 70313, HD 71722, HD 159492, AND F-TYPE: HD 104860

    SciTech Connect (OSTI)

    Morales, F. Y.; Bryden, G.; Werner, M. W. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Stapelfeldt, K. R., E-mail: Farisa@jpl.nasa.gov [NASA Goddard Space Flight Center, Exoplanets and Stellar Astrophysics Laboratory, Code 667, Greenbelt, MD 20771 (United States)

    2013-10-20

    We present dual-band Herschel/Photodetector Array Camera and Spectrometer imaging for four stars whose spectral energy distributions (SEDs) suggest two-ring disk architectures that mirror that of the asteroid-Kuiper Belt geometry of our own solar system. The Herschel observations at 100 ?m spatially resolve the cold/outer-dust component for each star-disk system for the first time, finding evidence of planetesimals at >100 AU, i.e., a larger size than assumed from a simple blackbody fit to the SED. By breaking the degeneracy between the grain properties and the dust's radial location, the resolved images help constrain the dust grain-size distribution for each system. Three of the observed stars are A-type and one solar-type. On the basis of the combined Spitzer/IRS+MIPS (5-70 ?m), the Herschel/PACS (100 and 160 ?m) dataset, and under the assumption of idealized spherical grains, we find that the cold/outer belts of the three A-type stars are well fit with a mixed ice/rock composition rather than pure rocky grains, while the debris around the solar-type star is consistent with either rock or ice/rock grains. For the solar-type star HD 104860, we find that the minimum grain size is larger than expected from the threshold set by radiative blowout. The A-type stars HD 71722 and HD 159492, on the other hand, require minimum grain sizes that are smaller than blowout for inner- and outer-ring populations. In the absence of spectral features for ice, we find that the behavior of the continuum can help constrain the composition of the grains (of icy nature and not pure rocky material) given the Herschel-resolved locations of the cold/outer-dust belts.

  18. A Chandra X-ray Study of NGC 1068: II. The Luminous X-ray Source Population

    E-Print Network [OSTI]

    David A. Smith; Andrew S. Wilson

    2003-03-17

    We present an analysis of the compact X-ray source population in the Seyfert~2 galaxy NGC 1068, imaged with Chandra. We find a total of 84 compact sources, of which 66 are projected onto the galactic disk of NGC 1068. Spectra of the brightest sources have been modeled with both multi-color disk blackbody and power-law models. The power-law model provides the better description of the spectrum for most of these sources. Five sources have 0.4-8 keV intrinsic luminosities greater than 10^{39} erg/s, assuming that their emission is isotropic and that they are associated with NGC 1068. We refer to these sources as Intermediate Luminosity X-ray Objects (IXOs). If these five sources are X-ray binaries accreting with luminosities that are both sub-Eddington and isotropic, then the implied source masses are >7 solar masses, and so they are inferred to be black holes. The brightest source has a much harder spectrum (Gamma = 0.9\\pm0.1) than that found in Galactic black hole candidates and other IXOs. It also shows large-amplitude variability on both short-term and long-term timescales. The ratio of the number of sources with luminosities greater than 2.1 x 10^{38} erg/s in the 0.4-8 keV band to the rate of massive star formation is the same, to within a factor of two, for NGC 1068, the Antennae, NGC 5194 (the main galaxy in M51), and the Circinus galaxy. This suggests that the rate of production of X-ray binaries per massive star is approximately the same for galaxies with currently active star formation, including ``starbursts''.

  19. Detection of a Rare Supersoft Outburst Event during a Suzaku Observation of 1E0102.2-7219

    E-Print Network [OSTI]

    D. Takei; M. Tsujimoto; S. Kitamoto; M. Morii; K. Ebisawa; Y. Maeda; E. D. Miller

    2007-06-02

    We report the detection of a transient X-ray source toward the Small Magellanic Cloud (SMC) using the X-ray Imaging Spectrometer (XIS) onboard the Suzaku telescope. The source was detected at the edge of the XIS image during a routine observation of the calibration source 1E 0102.2-7219, a supernova remnant in the SMC. We constrained the source position using ray-tracing simulations. No such transient source was found at the position in the other Suzaku observations nor in all the available archived images of other X-ray missions for the last ~28 years. The XIS spectrum can be explained by a single blackbody with a temperature of ~72 eV, and an interstellar extinction of ~4.9x10^{20} H atoms cm^{-2} consistent with the value to the SMC. An additional absorption edge at ~0.74 keV was also confirmed, which is presumably due to the absorption by helium-like oxygen ions. Assuming that the source is at the distance of the SMC, the X-ray luminosity in the 0.2-2.0 keV band is ~10^{37} erg s^{-1} and the radius of the source is ~10^{8} cm. The XIS light curve shows about a two-fold decline in X-ray flux during the 24 ks observation. Together with the archived data, the X-ray flux in the burst is at least three orders of magnitude brighter than the undetected quiescent level. All these properties are often seen among supersoft sources (SSSs). We conclude that the transient source is another example of SSS in the SMC.

  20. Chandra observations of the pulsar PSR B1929+10 and its environment

    E-Print Network [OSTI]

    Zdenka Misanovic; George Pavlov; Gordon Garmire

    2008-09-12

    We report on two Chandra observations of the 3-Myr pulsar B1929+10, which reveal a faint compact (~9"x5") nebula elongated in the direction perpendicular to the pulsar's proper motion, two patchy wings, and a possible short (~3") jet emerging from the pulsar. In addition, we detect a tail extending up to at least 4' in the direction opposite to the pulsar's proper motion, aligned with the 15'-long tail detected in ROSAT and XMM-Newton observations. The overall morphology of the nebula suggests that the shocked pulsar wind is confined by the ram pressure due to the pulsar's supersonic speed. The shape of the compact nebula in the immediate vicinity of the pulsar seems to be consistent with the current MHD models. However, since these models do not account yet for the change of the flow velocity at larger distances from the pulsar, they are not able to constrain the extent of the long pulsar tail. The luminosity of the whole nebula as seen by Chandra is ~10^30 ergs/s in the 0.3-8 keV band, for the distance of 361 pc. Using the Chandra and XMM-Newton data, we found that the pulsar spectrum is comprised of non-thermal (magnetospheric) and thermal components. The non-thermal component can be described by a power-law model with photon index ~1.7 and luminosity 1.7x10^30 ergs/s in the 0.3-10 keV band. The blackbody fit for the thermal component, which presumably emerges from hot polar caps, gives the temperature kT~0.3 keV and projected emitting area 3x10^3 m^2, corresponding to the bolometric luminosity ~(1-2)x10^30 ergs/s.

  1. A reconsideration of the noise equivalent power and the data analysis procedure for the infrared imaging video bolometers

    SciTech Connect (OSTI)

    Pandya, Shwetang N. Sano, Ryuichi; Peterson, Byron J.; Kobayashi, Masahiro; Mukai, Kiyofumi; Pandya, Santosh P.

    2014-12-15

    The infrared imaging video bolometer (IRVB) used for measurement of the two-dimensional (2D) radiation profiles from the Large Helical Device has been significantly upgraded recently to improve its signal to noise ratio, sensitivity, and calibration, which ultimately provides quantitative measurements of the radiation from the plasma. The reliability of the quantified data needs to be established by various checks. The noise estimates also need to be revised and more realistic values need to be established. It is shown that the 2D heat diffusion equation can be used for estimating the power falling on the IRVB foil, even with a significant amount of spatial variation in the thermal diffusivity across the area of the platinum foil found experimentally during foil calibration. The equation for the noise equivalent power density (NEPD) is re-derived to include the errors in the measurement of the thermophysical and the optical properties of the IRVB foil. The theoretical value estimated using this newly derived equation matches closely, within 5.5%, with the mean experimental value. The change in the contribution of each error term of the NEPD equation with rising foil temperature is also studied and the blackbody term is found to dominate the other terms at elevated operating temperatures. The IRVB foil is also sensitive to the charge exchange (CX) neutrals escaping from the plasma. The CX neutral contribution is estimated to be marginally higher than the noise equivalent power (NEP) of the IRVB. It is also established that the radiation measured by the IRVB originates from the impurity line radiation from the plasma and not from the heated divertor tiles. The change in the power density due to noise reduction measures such as data smoothing and averaging is found to be comparable to the IRVB NEPD. The precautions that need to be considered during background subtraction are also discussed with experimental illustrations. Finally, the analysis algorithm with all the improvements is validated and found to reproduce the input power well within 10% accuracy. This article answers many fundamental questions relevant to the IRVB and illustrates the care to be exercised while processing the IRVB data.

  2. Two superluminous supernovae from the early universe discovered by the supernova legacy survey

    SciTech Connect (OSTI)

    Howell, D. A. [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Goleta, CA 93117 (United States); Kasen, D. [Departments of Physics and Astronomy, University of California, Berkeley, Berkeley, CA 94720-7300 (United States); Lidman, C. [Australian Astronomical Observatory, P.O. Box 915, North Ryde, NSW 1670 (Australia); Sullivan, M. [School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ (United Kingdom); Conley, A. [Center for Astrophysics and Space Astronomy, University of Colorado, 389 UCB, Boulder, CO 80309-389 (United States); Astier, P.; Balland, C.; Guy, J.; Hardin, D.; Pain, R.; Regnault, N. [LPNHE, CNRS-IN2P3 and University of Paris VI and VII, F-75005 Paris (France); Carlberg, R. G. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H8 (Canada); Fouchez, D. [CPPM, CNRS-IN2P3 and University Aix Marseille II, Case 907, F-13288 Marseille Cedex 9 (France); Palanque-Delabrouille, N.; Rich, J.; Ruhlmann-Kleider, V. [DSM/IRFU/SPP, CEA-Saclay, F-91191 Gif-sur-Yvette (France); Perrett, K. [DRDC Ottawa, 3701 Carling Avenue, Ottawa, ON K1A 0Z4 (Canada); Pritchet, C. J. [Department of Physics and Astronomy, University of Victoria, P.O. Box 3055, Victoria, BC V8W 3P6 (Canada)

    2013-12-20

    We present spectra and light curves of SNLS 06D4eu and SNLS 07D2bv, two hydrogen-free superluminous supernovae (SNe) discovered by the Supernova Legacy Survey. At z = 1.588, SNLS 06D4eu is the highest redshift superluminous SN with a spectrum, at M{sub U} = –22.7 it is one of the most luminous SNe ever observed, and it gives a rare glimpse into the rest-frame ultraviolet where these SNe put out their peak energy. SNLS 07D2bv does not have a host galaxy redshift, but on the basis of the SN spectrum, we estimate it to be at z ? 1.5. Both SNe have similar observer-frame griz light curves, which map to rest-frame light curves in the U band and UV, rising in ?20 rest-frame days or longer and declining over a similar timescale. The light curves peak in the shortest wavelengths first, consistent with an expanding blackbody starting near 15,000 K and steadily declining in temperature. We compare the spectra with theoretical models, and we identify lines of C II, C III, Fe III, and Mg II in the spectra of SNLS 06D4eu and SCP 06F6 and find that they are consistent with an expanding explosion of only a few solar masses of carbon, oxygen, and other trace metals. Thus, the progenitors appear to be related to those suspected for SNe Ic. A high kinetic energy, 10{sup 52} erg, is also favored. Normal mechanisms of powering core-collapse or thermonuclear SNe do not seem to work for these SNe. We consider models powered by {sup 56}Ni decay and interaction with circumstellar material, but we find that the creation and spin-down of a magnetar with a period of 2 ms, a magnetic field of 2 × 10{sup 14} G, and a 3 M {sub ?} progenitor provides the best fit to the data.

  3. OPTICAL DISCOVERY OF PROBABLE STELLAR TIDAL DISRUPTION FLARES

    SciTech Connect (OSTI)

    Van Velzen, Sjoert; Farrar, Glennys R. [Center for Cosmology and Particle Physics, New York University, NY 10003 (United States); Gezari, Suvi [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Morrell, Nidia [Carnegie Observatories, Las Campanas Observatory, Casillas 601, La Serena (Chile); Zaritsky, Dennis [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Oestman, Linda [Institut de Fisica d'Altes Energies, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Barcelona) (Spain); Smith, Mathew [Department of Mathematics and Applied Mathematics, University of Cape Town, Rondebosch, 7701 (South Africa); Gelfand, Joseph [New York University-Abu Dhabi, Abu Dhabi (United Arab Emirates); Drake, Andrew J., E-mail: s.vanvelzen@astro.ru.nl [Center for Advance Computing Research, California Institute of Technology, Pasadena, CA 91225 (United States)

    2011-11-10

    Using archival Sloan Digital Sky Survey (SDSS) multi-epoch imaging data (Stripe 82), we have searched for the tidal disruption of stars by supermassive black holes in non-active galaxies. Two candidate tidal disruption events (TDEs) are identified. The TDE flares have optical blackbody temperatures of 2 Multiplication-Sign 10{sup 4} K and observed peak luminosities of M{sub g} = -18.3 and -20.4 ({nu}L{sub {nu}} = 5 Multiplication-Sign 10{sup 42}, 4 Multiplication-Sign 10{sup 43} erg s{sup -1}, in the rest frame); their cooling rates are very low, qualitatively consistent with expectations for tidal disruption flares. The properties of the TDE candidates are examined using (1) SDSS imaging to compare them to other flares observed in the search, (2) UV emission measured by GALEX, and (3) spectra of the hosts and of one of the flares. Our pipeline excludes optically identifiable AGN hosts, and our variability monitoring over nine years provides strong evidence that these are not flares in hidden AGNs. The spectra and color evolution of the flares are unlike any SN observed to date, their strong late-time UV emission is particularly distinctive, and they are nuclear at high resolution arguing against these being first cases of a previously unobserved class of SNe or more extreme examples of known SN types. Taken together, the observed properties are difficult to reconcile with an SN or an AGN-flare explanation, although an entirely new process specific to the inner few hundred parsecs of non-active galaxies cannot be excluded. Based on our observed rate, we infer that hundreds or thousands of TDEs will be present in current and next-generation optical synoptic surveys. Using the approach outlined here, a TDE candidate sample with O(1) purity can be selected using geometric resolution and host and flare color alone, demonstrating that a campaign to create a large sample of TDEs, with immediate and detailed multi-wavelength follow-up, is feasible. A by-product of this work is quantification of the power spectrum of extreme flares in AGNs.

  4. FHR Process Instruments

    SciTech Connect (OSTI)

    Holcomb, David Eugene

    2015-01-01

    Fluoride salt-cooled High temperature Reactors (FHRs) are entering into early phase engineering development. Initial candidate technologies have been identified to measure all of the required process variables. The purpose of this paper is to describe the proposed measurement techniques in sufficient detail to enable assessment of the proposed instrumentation suite and to support development of the component technologies. This paper builds upon the instrumentation chapter of the recently published FHR technology development roadmap. Locating instruments outside of the intense core radiation and high-temperature fluoride salt environment significantly decreases their environmental tolerance requirements. Under operating conditions, FHR primary coolant salt is a transparent, low-vapor-pressure liquid. Consequently, FHRs can employ standoff optical measurements from above the salt pool to assess in-vessel conditions. For example, the core outlet temperature can be measured by observing the fuel s blackbody emission. Similarly, the intensity of the core s Cerenkov glow indicates the fission power level. Short-lived activation of the primary coolant provides another means for standoff measurements of process variables. The primary coolant flow and neutron flux can be measured using gamma spectroscopy along the primary coolant piping. FHR operation entails a number of process measurements. Reactor thermal power and core reactivity are the most significant variables for process control. Thermal power can be determined by measuring the primary coolant mass flow rate and temperature rise across the core. The leading candidate technologies for primary coolant temperature measurement are Au-Pt thermocouples and Johnson noise thermometry. Clamp-on ultrasonic flow measurement, that includes high-temperature tolerant standoffs, is a potential coolant flow measurement technique. Also, the salt redox condition will be monitored as an indicator of its corrosiveness. Both electrochemical techniques and optical spectroscopy are candidate fluoride salt redox measurement methods. Coolant level measurement can be performed using radar-level gauges located in standpipes above the reactor vessel. While substantial technical development remains for most of the instruments, industrially compatible instruments based upon proven technology can be reasonably extrapolated from the current state of the art.

  5. HERSCHEL's ''COLD DEBRIS DISKS'': BACKGROUND GALAXIES OR QUIESCENT RIMS OF PLANETARY SYSTEMS?

    SciTech Connect (OSTI)

    Krivov, A. V.; Loehne, T.; Mutschke, H.; Neuhaeuser, R. [Astrophysikalisches Institut und Universitaetssternwarte, Friedrich-Schiller-Universitaet Jena, Schillergaesschen 2-3, D-07745 Jena (Germany); Eiroa, C.; Marshall, J. P.; Mustill, A. J. [Departamento de Fisica Teorica, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco, E-28049 Madrid (Spain); Montesinos, B. [Departamento de Astrofisica, Centro de Astrobiologia (CAB, CSIC-INTA), ESAC Campus, P.O. Box 78, E-28691 Villanueva de la Canada, Madrid (Spain); Del Burgo, C. [Instituto Nacional de Astrofisica, Optica y Electronica (INAOE), Apartado Postal 51 y 216, 72000 Puebla, Pue. (Mexico); Absil, O. [Institut d'Astrophysique et de Geophysique, Universite de Liege, Allee du 6 Aout 17, B-4000 Liege (Belgium); Ardila, D. [NASA Herschel Science Center, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Augereau, J.-C.; Ertel, S.; Lebreton, J. [UJF-Grenoble 1/CNRS-INSU, Institut de Planetologie et d'Astrophysique de Grenoble (IPAG), UMR 5274, F-38041 Grenoble (France); Bayo, A. [European Southern Observatory, Alonso de Cordova 3107, Vitacura, Santiago (Chile); Bryden, G. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Danchi, W. [NASA Goddard Space Flight Center, Exoplanets and Stellar Astrophysics, Code 667, Greenbelt, MD 20771 (United States); Liseau, R. [Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE-43992, Onsala (Sweden); Mora, A. [ESA-ESAC Gaia SOC, P.O. Box 78, E-28691 Villanueva de la Canada, Madrid (Spain); Pilbratt, G. L., E-mail: krivov@astro.uni-jena.de [ESA Astrophysics and Fundamental Physics Missions Division, ESTEC/SRE-SA, Keplerlaan 1, 2201 AZ Noordwijk (Netherlands); and others

    2013-07-20

    Infrared excesses associated with debris disk host stars detected so far peak at wavelengths around {approx}100 {mu}m or shorter. However, 6 out of 31 excess sources studied in the Herschel Open Time Key Programme, DUNES, have been seen to show significant-and in some cases extended-excess emission at 160 {mu}m, which is larger than the 100 {mu}m excess. This excess emission has been attributed to circumstellar dust and has been suggested to stem from debris disks colder than those known previously. Since the excess emission of the cold disk candidates is extremely weak, challenging even the unrivaled sensitivity of Herschel, it is prudent to carefully consider whether some or even all of them may represent unrelated galactic or extragalactic emission, or even instrumental noise. We re-address these issues using several distinct methods and conclude that it is highly unlikely that none of the candidates represents a true circumstellar disk. For true disks, both the dust temperatures inferred from the spectral energy distributions and the disk radii estimated from the images suggest that the dust is nearly as cold as a blackbody. This requires the grains to be larger than {approx}100 {mu}m, even if they are rich in ices or are composed of any other material with a low absorption in the visible. The dearth of small grains is puzzling, since collisional models of debris disks predict that grains of all sizes down to several times the radiation pressure blowout limit should be present. We explore several conceivable scenarios: transport-dominated disks, disks of low dynamical excitation, and disks of unstirred primordial macroscopic grains. Our qualitative analysis and collisional simulations rule out the first two of these scenarios, but show the feasibility of the third one. We show that such disks can indeed survive for gigayears, largely preserving the primordial size distribution. They should be composed of macroscopic solids larger than millimeters, but smaller than a few kilometers in size. If larger planetesimals were present, then they would stir the disk, triggering a collisional cascade and thus causing production of small debris, which is not seen. Thus, planetesimal formation, at least in the outer regions of the systems, has stopped before 'cometary' or 'asteroidal' sizes were reached.

  6. Rapidly evolving and luminous transients from Pan-STARRS1

    SciTech Connect (OSTI)

    Drout, M. R.; Chornock, R.; Soderberg, A. M.; Sanders, N. E.; McKinnon, R.; Milisavljevic, D.; Margutti, R.; Berger, E.; Calkins, M.; Fong, W.; Kirshner, R. P.; Lunnan, R. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Rest, A. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Foley, R. J. [Astronomy Department, University of Illinois at Urbana-Champaign, 1002 West Green Street, Urbana, IL 61801 (United States); Gezari, S. [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Huber, M. E. [Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI 96822 (United States); Kankare, E.; Mattila, S. [Finnish Centre for Astronomy with ESO (FINCA), University of Turku, Väisäläntie 20, FI-21500 Piikkiö (Finland); Leibler, C. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95060 (United States); Marion, G. H., E-mail: mdrout@cfa.harvard.edu [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States); and others

    2014-10-10

    In the past decade, several rapidly evolving transients have been discovered whose timescales and luminosities are not easily explained by traditional supernovae (SNe) models. The sample size of these objects has remained small due, at least in part, to the challenges of detecting short timescale transients with traditional survey cadences. Here we present the results from a search within the Pan-STARRS1 Medium Deep Survey (PS1-MDS) for rapidly evolving and luminous transients. We identify 10 new transients with a time above half-maximum (t {sub 1/2}) of less than 12 days and –16.5 > M > –20 mag. This increases the number of known events in this region of SN phase space by roughly a factor of three. The median redshift of the PS1-MDS sample is z = 0.275 and they all exploded in star-forming galaxies. In general, the transients possess faster rise than decline timescale and blue colors at maximum light (g {sub P1} – r {sub P1} ? –0.2). Best-fit blackbodies reveal photospheric temperatures/radii that expand/cool with time and explosion spectra taken near maximum light are dominated by a blue continuum, consistent with a hot, optically thick, ejecta. We find it difficult to reconcile the short timescale, high peak luminosity (L > 10{sup 43} erg s{sup –1}), and lack of UV line blanketing observed in many of these transients with an explosion powered mainly by the radioactive decay of {sup 56}Ni. Rather, we find that many are consistent with either (1) cooling envelope emission from the explosion of a star with a low-mass extended envelope that ejected very little (<0.03 M {sub ?}) radioactive material, or (2) a shock breakout within a dense, optically thick, wind surrounding the progenitor star. After calculating the detection efficiency for objects with rapid timescales in the PS1-MDS we find a volumetric rate of 4800-8000 events yr{sup –1} Gpc{sup –3} (4%-7% of the core-collapse SN rate at z = 0.2).

  7. Time resolved spectroscopy of SGR J1550–5418 bursts detected with Fermi/gamma-ray burst monitor

    SciTech Connect (OSTI)

    Younes, G. [Universities Space Research Association, 6767 Old Madison Pike, Suite 450, Huntsville, AL 35806 (United States); Kouveliotou, C.; Collazzi, A. [Astrophysics Office, ZP 12, NASA-Marshall Space Flight Center, Huntsville, AL 35812 (United States); Van der Horst, A. J.; Watts, A. L.; Huppenkothen, D.; Van der Klis, M.; Van Putten, T. [Astronomical Institute "Anton Pannekoek," University of Amsterdam, Postbus 94249, 1090 GE Amsterdam (Netherlands); Baring, M. G. [Department of Physics and Astronomy, Rice University, MS-108, P.O. Box 1892, Houston, TX 77251 (United States); Granot, J. [Department of Natural Sciences, The Open University of Israel, 1 University Road, P.O. Box 808, Raánana 43537 (Israel); Bhat, P. N.; Gorgone, N. [University of Alabama in Huntsville CSPAR, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Gehrels, N.; Mcenery, J. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Gö?ü?, E.; Kaneko, Y.; Lin, L. [Sabanc? University, Orhanl?-Tuzla, ?stanbul 34956 (Turkey); Gruber, D.; Von Kienlin, A. [Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, Postfach 1312, D-85748 Garching (Germany); Grunblatt, S. [University of Hawaii at Manoa, 2500 Campus Road, Honolulu, HI 96822 (United States); and others

    2014-04-10

    We report on a time-resolved spectroscopy of the 63 brightest bursts of SGR J1550–5418, detected with the Fermi/Gamma-ray Burst Monitor during its 2008-2009 intense bursting episode. We performed spectral analysis down to 4 ms timescales to characterize the spectral evolution of the bursts. Using a Comptonized model, we find that the peak energy, E {sub peak}, anti-correlates with flux, while the low-energy photon index remains constant at ? – 0.8 up to a flux limit F ? 10{sup –5} erg s{sup –1} cm{sup –2}. Above this flux value, the E {sub peak}–flux correlation changes sign, and the index positively correlates with the flux reaching ?1 at the highest fluxes. Using a two blackbody model, we find that the areas and fluxes of the two emitting regions correlate positively. Further, we study here for the first time the evolution of the temperatures and areas as a function of flux. We find that the area–kT relation follows the lines of constant luminosity at the lowest fluxes, R {sup 2}?kT {sup –4}, with a break at the higher fluxes (F > 10{sup –5.5} erg s{sup –1} cm{sup –2}). The area of the high-kT component increases with the flux while its temperature decreases, which we interpret as being due to an adiabatic cooling process. The area of the low-kT component, on the other hand, appears to saturate at the highest fluxes, toward R {sub max} ? 30 km. Assuming that crust quakes are responsible for soft gamma repeater (SGR) bursts and considering R {sub max} as the maximum radius of the emitting photon-pair plasma fireball, we relate this saturation radius to a minimum excitation radius of the magnetosphere, and we put a lower limit on the internal magnetic field of SGR J1550–5418, B {sub int} ? 4.5 × 10{sup 15} G.

  8. THE 2011 ERUPTION OF THE RECURRENT NOVA T PYXIDIS: THE DISCOVERY, THE PRE-ERUPTION RISE, THE PRE-ERUPTION ORBITAL PERIOD, AND THE REASON FOR THE LONG DELAY

    SciTech Connect (OSTI)

    Schaefer, Bradley E.; Landolt, Arlo U. [Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803 (United States); Linnolt, Michael [American Association of Variable Star Observers, 49 Bay State Road, Cambridge, MA 02138 (United States); Stubbings, Rod [Tetoora Observatory, Tetoora Road, Victoria (Australia); Pojmanski, Grzegorz [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Plummer, Alan [Variable Stars South, Linden Observatory, 105 Glossop Road, Linden, NSW (Australia); Kerr, Stephen [American Association of Variable Star Observers, Variable Stars South, Astronomical Association of Queensland, 22 Green Avenue, Glenlee, Queensland (Australia); Nelson, Peter [Ellinbank Observatory, 1105 Hazeldean Road, Ellinbank 3821, Victoria (Australia); Carstens, Rolf [American Association of Variable Star Observers, Variable Stars South, CBA, Geyserland Observatory, 120 Homedale Street, Rotorua 3015 (New Zealand); Streamer, Margaret [Lexy's Palace Observatory, 3 Lupin Place, Murrumbateman, NSW (Australia); Richards, Tom [Variable Stars South, Pretty Hill Observatory, P.O. Box 323, Kangaroo Ground 3097, Victoria (Australia); Myers, Gordon [Center for Backyard Astrophysics, Columbia University, 538 West 120th Street, New York, NY 10027 (United States); Dillon, William G. [American Association of Variable Star Observers, 4703 Birkenhead Circle, Missouri City, TX 77459 (United States)

    2013-08-10

    We report the discovery by M. Linnolt on JD 2,455,665.7931 (UT 2011 April 14.29) of the sixth eruption of the recurrent nova T Pyxidis. This discovery was made just as the initial fast rise was starting, so with fast notification and response by observers worldwide, the entire initial rise was covered (the first for any nova), and with high time resolution in three filters. The speed of the rise peaked at 9 mag day{sup -1}, while the light curve is well fit over only the first two days by a model with a uniformly expanding sphere. We also report the discovery by R. Stubbings of a pre-eruption rise starting 18 days before the eruption, peaking 1.1 mag brighter than its long-time average, and then fading back toward quiescence 4 days before the eruption. This unique and mysterious behavior is only the fourth known (with V1500 Cyg, V533 Her, and T CrB) anticipatory rise closely spaced before a nova eruption. We present 19 timings of photometric minima from 1986 to 2011 February, where the orbital period is fast increasing with P/ P-dot =+313,000 yr. From 2008 to 2011, T Pyx had a small change in this rate of increase, so that the orbital period at the time of eruption was 0.07622950 {+-} 0.00000008 days. This strong and steady increase of the orbital period can only come from mass transfer, for which we calculate a rate of (1.7-3.5) Multiplication-Sign 10{sup -7} M{sub Sun} yr{sup -1}. We report 6116 magnitudes between 1890 and 2011, for an average B = 15.59 {+-} 0.01 from 1967 to 2011, which allows for an eruption in 2011 if the blue flux is nearly proportional to the accretion rate. The ultraviolet-optical-infrared spectral energy distribution is well fit by a power law with f{sub {nu}}{proportional_to}{nu}{sup 1.0}, although the narrow ultraviolet region has a tilt with a fit of f{sub {nu}}{proportional_to}{nu}{sup 1/3}. We prove that most of the T Pyx light is not coming from a disk, or any superposition of blackbodies, but rather is coming from some nonthermal source. We confirm the extinction measure from IUE with E(B - V) = 0.25 {+-} 0.02 mag.

  9. Disk radii and grain sizes in Herschel-resolved debris disks

    SciTech Connect (OSTI)

    Pawellek, Nicole; Krivov, Alexander V. [Astrophysikalisches Institut und Universitätssternwarte, Friedrich-Schiller-Universität Jena, Schillergäßchen 2-3, 07745 Jena (Germany); Marshall, Jonathan P. [School of Physics, University of New South Wales, Sydney NSW 2052 (Australia); Montesinos, Benjamin [Departmento de Astrofísica, Centro de Astrobiología (CAB, CSIC-INTA), ESAC Campus, P.O. Box 78, E-28691 Villanueva de la Cañada, Madrid (Spain); Ábrahám, Péter; Moór, Attila [Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, P.O. Box 67, H-1525 Budapest (Hungary); Bryden, Geoffrey [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Eiroa, Carlos [Departamento de Física Teórica, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid (Spain)

    2014-09-01

    The radii of debris disks and the sizes of their dust grains are important tracers of the planetesimal formation mechanisms and physical processes operating in these systems. Here we use a representative sample of 34 debris disks resolved in various Herschel Space Observatory (Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA) programs to constrain the disk radii and the size distribution of their dust. While we modeled disks with both warm and cold components, and identified warm inner disks around about two-thirds of the stars, we focus our analysis only on the cold outer disks, i.e., Kuiper-belt analogs. We derive the disk radii from the resolved images and find a large dispersion for host stars of any spectral class, but no significant trend with the stellar luminosity. This argues against ice lines as a dominant player in setting the debris disk sizes, since the ice line location varies with the luminosity of the central star. Fixing the disk radii to those inferred from the resolved images, we model the spectral energy distribution to determine the dust temperature and the grain size distribution for each target. While the dust temperature systematically increases toward earlier spectral types, the ratio of the dust temperature to the blackbody temperature at the disk radius decreases with the stellar luminosity. This is explained by a clear trend of typical sizes increasing toward more luminous stars. The typical grain sizes are compared to the radiation pressure blowout limit s {sub blow} that is proportional to the stellar luminosity-to-mass ratio and thus also increases toward earlier spectral classes. The grain sizes in the disks of G- to A-stars are inferred to be several times s {sub blow} at all stellar luminosities, in agreement with collisional models of debris disks. The sizes, measured in the units of s {sub blow}, appear to decrease with the luminosity, which may be suggestive of the disk's stirring level increasing toward earlier-type stars. The dust opacity index ? ranges between zero and two, and the size distribution index q varies between three and five for all the disks in the sample.

  10. On the efficacy of imploding plasma liners for magnetized fusion target compression

    SciTech Connect (OSTI)

    Parks, P. B.

    2008-06-15

    A new theoretical model is formulated to study the idea of merging a spherical array of converging plasma jets to form a 'plasma liner' that further converges to compress a magnetized plasma target to fusion conditions [Y. C. F. Thio et al., 'Magnetized target fusion in a spheroidal geometry with standoff drivers', Current Trends in International Fusion Research II, edited by E. Panarella (National Research Council Canada, Ottawa, Canada, 1999)]. For a spherically imploding plasma liner shell with high initial Mach number (M=liner speed/sound speed) the rise in liner density with decreasing radius r goes as {rho}{approx}1/r{sup 2}, for any constant adiabatic index {gamma}=d ln p/d ln {rho}. Accordingly, spherical convergence amplifies the ram pressure of the liner on target by the factor A{approx}C{sup 2}, indicating strong coupling to its radial convergence C=r{sub m}/R, where r{sub m}(R)=jet merging radius (compressed target radius), and A=compressed target pressure/initial liner ram pressure. Deuterium-tritium (DT) plasma liners with initial velocity {approx}100 km/s and {gamma}=5/3, need to be hypersonic M{approx}60 and thus cold in order to realize values of A{approx}10{sup 4} necessary for target ignition. For optically thick DT liners, T<2 eV, n>10{sup 19}-10{sup 20} cm{sup -3}, blackbody radiative cooling is appreciable and may counteract compressional heating during the later stages of the implosion. The fluid then behaves as if the adiabatic index were depressed below 5/3, which in turn means that the same amplification A=1.6x10{sup 4} can be accomplished with a reduced initial Mach number M{approx_equal}12.7({gamma}-0.3){sup 4.86}, valid in the range (10

  11. SWIFT X-RAY AND ULTRAVIOLET MONITORING OF THE CLASSICAL NOVA V458 VUL (NOVA VUL 2007)

    SciTech Connect (OSTI)

    Ness, J.-U. [European Space Astronomy Centre, P.O. Box 78, 28691 Villanueva de la Canada, Madrid (Spain); Drake, J. J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Beardmore, A. P.; Evans, P. A.; Osborne, J. P.; Page, K. L. [Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom); Boyd, D. [BAA VSS, 5 Silver Lane, West Challow, Wantage, OX12 9TX (United Kingdom); Bode, M. F. [Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead CH41 1LD (United Kingdom); Brady, S. [AAVSO, 5 Melba Drive, Hudson, NH 03051 (United States); Gaensicke, B. T.; Steeghs, D. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Kitamoto, S.; Takei, D. [Department of Physics, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo 171-8501 (Japan); Knigge, C. [School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ (United Kingdom); Miller, I. [BAA VSS, Furzehill House, Ilston, Swansea SA2 7LE (United Kingdom); Rodriguez-Gil, P. [Isaac Newton Group, PO Ap. de Correos 321, 38700 Sta. Cruz de la Palma (Spain); Schwarz, G. [Department of Geology and Astronomy, West Chester University, West Chester, PA 19383 (United States); Staels, B. [CBA Flanders, Alan Guth Observatory, Koningshofbaan 51, Hofstade, Aalst (Belgium); Tsujimoto, M. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Wesson, R. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom)], E-mail: juness@sciops.esa.int (and others)

    2009-05-15

    We describe the highly variable X-ray and UV emission of V458 Vul (Nova Vul 2007), observed by Swift between 1 and 422 days after outburst. Initially bright only in the UV, V458 Vul became a variable hard X-ray source due to optically thin thermal emission at kT = 0.64 keV with an X-ray band unabsorbed luminosity of 2.3 x 10{sup 34} erg s{sup -1} during days 71-140. The X-ray spectrum at this time requires a low Fe abundance (0.2{sup +0.3} {sub -0.1} solar), consistent with a Suzaku measurement around the same time. On day 315 we find a new X-ray spectral component which can be described by a blackbody with temperature of kT = 23{sup +9} {sub -5} eV, while the previous hard X-ray component has declined by a factor of 3.8. The spectrum of this soft X-ray component resembles those typically seen in the class of supersoft sources (SSS) which suggests that the nova ejecta were starting to clear and/or that the white dwarf photosphere is shrinking to the point at which its thermal emission reaches into the X-ray band. We find a high degree of variability in the soft component with a flare rising by an order of magnitude in count rate in 0.2 days. In the following observations on days 342.4-383.6, the soft component was not seen, only to emerge again on day 397. The hard component continued to evolve, and we found an anticorrelation between the hard X-ray emission and the UV emission, yielding a Spearman rank probability of 97%. After day 397, the hard component was still present, was variable, and continued to fade at an extremely slow rate but could not be analyzed owing to pile-up contamination from the bright SSS component.

  12. LONG-TERM SPECTRAL VARIATIONS OF ULTRALUMINOUS X-RAY SOURCES IN THE INTERACTING GALAXY SYSTEMS M 51 AND NGC 4490/85

    SciTech Connect (OSTI)

    Yoshida, Tessei; Ebisawa, Ken; Tsujimoto, Masahiro [Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, 3-1-1 Yoshinodai, Chuo, Sagamihara, Kanagawa 252-5210 (Japan); Matsushita, Kyoko [Department of Physics, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku, Tokyo 162-8601 (Japan); Kawaguchi, Toshihiro, E-mail: yoshida.tessei@ac.jaxa.j [Center for Computational Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan)

    2010-10-10

    Variable ultraluminous X-ray sources (ULXs), which are considered to be black hole binaries (BHBs), are known to show state transitions similar to Galactic BHBs. However, the relation between the ULX states and the Galactic BHB states is still unclear, primarily due to the less well-understood behaviors of ULXs in contrast to the Galactic BHBs. Here, we report a statistical X-ray spectral study of 34 energy spectra from seven bright ULXs in the interacting galaxy systems M 51 and NGC 4490/85, using archive data from multiple Chandra and XMM-Newton observations spanning a few years. In order to compare them with Galactic BHB states, we applied representative spectral models of BHBs-a power-law (PL), a multi-color disk blackbody (MCD), and a slim-disk model-to all the ULX spectra. We found a hint of a bimodal structure in the luminosity distribution of the samples, suggesting that ULXs have two states that respectively have typical luminosities of (3-6)x 10{sup 39} and (1.5-3)x 10{sup 39} ergs s{sup -1}. Most spectra in the brighter state are explained by the MCD or the slim-disk model, whereas those in the fainter state are explained by the PL model. In particular, the slim-disk model successfully explains the observed spectral variations of NGC 4490/85 ULX-6 and ULX-8 by changes of the mass accretion rate to a black hole of an estimated mass of <40 M{sub sun}. From the best-fit model parameters of each state, we speculate that the brighter state in these two ULXs corresponds to the brightest state of Galactic BHBs, which is often called the 'apparently standard state'. The fainter state of the ULXs has a PL-shaped spectrum, but the photon index range is much wider than that seen in any single state of Galactic BHBs. We thus speculate that it is a state unique to ULXs. Some sources show much fainter and steeper spectra than the faint state, which we identified as yet another state.

  13. High-Efficiency Nitride-Based Solid-State Lighting

    SciTech Connect (OSTI)

    Paul T. Fini; Shuji Nakamura

    2005-07-30

    In this final technical progress report we summarize research accomplished during Department of Energy contract DE-FC26-01NT41203, entitled ''High-Efficiency Nitride-Based Solid-State Lighting''. Two teams, from the University of California at Santa Barbara (Principle Investigator: Dr. Shuji Nakamura) and the Lighting Research Center at Rensselaer Polytechnic Institute (led by Dr. N. Narendran), pursued the goals of this contract from thin film growth, characterization, and packaging/luminaire design standpoints. The UCSB team initially pursued the development of blue gallium nitride (GaN)-based vertical-cavity surface-emitting lasers, as well as ultraviolet GaN-based light emitting diodes (LEDs). In Year 2, the emphasis shifted to resonant-cavity light emitting diodes, also known as micro-cavity LEDs when extremely thin device cavities are fabricated. These devices have very directional emission and higher light extraction efficiency than conventional LEDs. Via the optimization of thin-film growth and refinement of device processing, we decreased the total cavity thickness to less than 1 {micro}m, such that micro-cavity effects were clearly observed and a light extraction efficiency of over 10% was reached. We also began the development of photonic crystals for increased light extraction, in particular for so-called ''guided modes'' which would otherwise propagate laterally in the device and be re-absorbed. Finally, we pursued the growth of smooth, high-quality nonpolar a-plane and m-plane GaN films, as well as blue light emitting diodes on these novel films. Initial nonpolar LEDs showed the expected behavior of negligible peak wavelength shift with increasing drive current. M-plane LEDs in particular show promise, as unpackaged devices had unsaturated optical output power of {approx} 3 mW at 200 mA drive current. The LRC's tasks were aimed at developing the subcomponents necessary for packaging UCSB's light emitting diodes, and packaging them to produce a white light fixture. During the third and final year of the project, the LRC team investigated alternate packaging methods for the white LED device to achieve at least 25 percent more luminous efficacy than traditional white LEDs; conducted optical ray-tracing analyses and human factors studies to determine the best form factor for the white light source under development, in terms of high luminous efficacy and greater acceptance by subjects; and developed a new die encapsulant using silicone-epoxy resins that showed less yellowing and slower degradation. At the conclusion of this project, the LRC demonstrated a new packaging method, called scattered photon extraction (SPE), that produced an average luminous flux and corresponding average efficacy of 90.7 lm and 36.3 lm/W, respectively, compared with 56.5 lm and 22.6 lm/W for a similar commercial white LED package. At low currents, the SPE package emitted white light with an efficacy of over 80 lm/W and had chromaticity values very close to the blackbody locus. The SPE package showed an overall improvement of 61% for this particular comparison, exceeding the LRC's third-year goal of 25% improvement.

  14. TEMPORAL AND SPECTRAL EVOLUTION IN X- AND {gamma}-RAYS OF MAGNETAR 1E 1547.0-5408 SINCE ITS 2008 OCTOBER OUTBURST: THE DISCOVERY OF A TRANSIENT HARD PULSED COMPONENT AFTER ITS 2009 JANUARY OUTBURST

    SciTech Connect (OSTI)

    Kuiper, L.; Hermsen, W. [SRON-National Institute for Space Research, Sorbonnelaan 2, 3584 CA, Utrecht (Netherlands); Den Hartog, P. R. [Stanford University HEPL/KIPAC Physics, 382 via Pueblo Mall Stanford, CA 94305 (United States); Urama, J. O., E-mail: L.M.Kuiper@sron.nl [Department of Physics and Astronomy, University of Nigeria, Nsukka (Nigeria)

    2012-04-01

    The magnetar 1E 1547.0-5408 exhibited outbursts in 2008 October and 2009 January. In this paper, we present in great detail the evolution of the temporal and spectral characteristics of the persistent total and pulsed emission of 1E 1547.0-5408 between {approx}1 and 300 keV starting on 2008 October 3 and ending in 2011 January. We analyzed data collected with the Rossi X-ray Timing Explorer (RXTE) the International Gamma-Ray Astrophysics Laboratory (INTEGRAL), and the Swift satellite. We report the evolution of the pulse frequency, and the measurement at the time of the onset of the 2009 January outburst of an insignificant jump in frequency, but a major frequency derivative jump {Delta}{nu}-dot of +(1.30 {+-} 0.14) Multiplication-Sign 10{sup -11} Hz s{sup -1} ({Delta}{nu}-dot/{nu}-dot of -0.69 {+-} 0.07). Before this {nu}-dot glitch, a single broad pulse is detected, mainly for energies below {approx}10 keV. Surprisingly, {approx}11 days after the glitch a new transient high-energy (up to {approx}150 keV) pulse appears with a Gaussian shape and width 0.23, shifted in phase by {approx}0.31 compared to the low-energy pulse, which smoothly fades to undetectable levels in {approx}350 days. We report the evolution of the pulsed-emission spectra. For energies 2.5-10 keV all pulsed spectra are very soft with photon indices {Gamma} between -4.6 and -3.9. For {approx}10-150 keV, after the {nu}-dot glitch, we report hard non-thermal pulsed spectra, similar to what has been reported for the persistent pulsed emission of some anomalous X-ray pulsars. This pulsed hard X-ray emission reached maximal luminosity 70 {+-} 30 days after the glitch epoch, followed by a gradual decrease by more than a factor of 10 over {approx}300 days. These characteristics differ from those of the total emission. Both, the total soft X-ray (1-10 keV) and hard X-ray (10-150 keV) fluxes, were maximal already 2 days after the 2009 January outburst, and decayed by a factor of {approx}>3 over {approx}400 days. The total spectra can be described with a blackbody (kT values varying in the range 0.57-0.74 keV) plus a single power-law model. The photon index exhibited a hardening ({approx} - 1.4 to {approx} - 0.9) with time, correlated with a decrease in flux in the 20-300 keV band. We discuss these findings in the framework of the magnetar model.

  15. High Efficiency, Illumination Quality OLEDs for Lighting

    SciTech Connect (OSTI)

    Joseph Shiang; James Cella; Kelly Chichak; Anil Duggal; Kevin Janora; Chris Heller; Gautam Parthasarathy; Jeffery Youmans; Joseph Shiang

    2008-03-31

    The goal of the program was to demonstrate a 45 lumen per watt white light device based upon the use of multiple emission colors through the use of solution processing. This performance level is a dramatic extension of the team's previous 15 LPW large area illumination device. The fundamental material system was based upon commercial polymer materials. The team was largely able to achieve these goals, and was able to deliver to DOE a 90 lumen illumination source that had an average performance of 34 LPW a 1000 cd/m{sup 2} with peak performances near 40LPW. The average color temperature is 3200K and the calculated CRI 85. The device operated at a brightness of approximately 1000cd/m{sup 2}. The use of multiple emission colors particularly red and blue, provided additional degrees of design flexibility in achieving white light, but also required the use of a multilayered structure to separate the different recombination zones and prevent interconversion of blue emission to red emission. The use of commercial materials had the advantage that improvements by the chemical manufacturers in charge transport efficiency, operating life and material purity could be rapidly incorporated without the expenditure of additional effort. The program was designed to take maximum advantage of the known characteristics of these material and proceeded in seven steps. (1) Identify the most promising materials, (2) assemble them into multi-layer structures to control excitation and transport within the OLED, (3) identify materials development needs that would optimize performance within multilayer structures, (4) build a prototype that demonstrates the potential entitlement of the novel multilayer OLED architecture (5) integrate all of the developments to find the single best materials set to implement the novel multilayer architecture, (6) further optimize the best materials set, (7) make a large area high illumination quality white OLED. A photo of the final deliverable is shown. In 2003, a large area, OLED based illumination source was demonstrated that could provide light with a quality, quantity, and efficiency on par with what can be achieved with traditional light sources. The demonstration source was made by tiling together 16 separate 6-inch x 6-inch blue-emitting OLEDs. The efficiency, total lumen output, and lifetime of the OLED based illumination source were the same as what would be achieved with an 80 watt incandescent bulb. The devices had an average efficacy of 15 LPW and used solution-processed OLEDs. The individual 6-inch x 6-inch devices incorporated three technology strategies developed specifically for OLED lighting -- downconversion for white light generation, scattering for outcoupling efficiency enhancement, and a scalable monolithic series architecture to enable large area devices. The downconversion approach consists of optically coupling a blue-emitting OLED to a set of luminescent layers. The layers are chosen to absorb the blue OLED emission and then luminescence with high efficiency at longer wavelengths. The composition and number of layers are chosen so that the unabsorbed blue emission and the longer wavelength re-emission combine to make white light. A downconversion approach has the advantage of allowing a wide variety of colors to be made from a limited set of blue emitters. In addition, one does not have to carefully tune the emission wavelength of the individual electro-luminescent species within the OLED device in order to achieve white light. The downconversion architecture used to develop the 15LPW large area light source consisted of a polymer-based blue-emitting OLED and three downconversion layers. Two of the layers utilized perylene based dyes from BASF AG of Germany with high quantum efficiency (>98%) and one of the layers consisted of inorganic phosphor particles (Y(Gd)AG:Ce) with a quantum efficiency of {approx}85%. By independently varying the optical density of the downconversion layers, the overall emission spectrum could be adjusted to maximize performance for lighting (e.g. blackbody temp