National Library of Energy BETA

Sample records for lone star gas

  1. Lone Star Transmission LLC | Open Energy Information

    Open Energy Info (EERE)

    Transmission LLC Jump to: navigation, search Name: Lone Star Transmission LLC Place: Juno Beach, Florida Zip: 33408 Product: Wholly owned subsidiary of FPL Energy, developing...

  2. Clean Cities: Lone Star Clean Fuels Alliance (Central Texas)...

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

    Lone Star Clean Fuels Alliance (Central Texas) Coalition The Lone Star Clean Fuels Alliance (Central Texas) coalition works with vehicle fleets, fuel providers, community leaders,...

  3. Lone Star I (Q2) Wind Farm | Open Energy Information

    Open Energy Info (EERE)

    Q2) Wind Farm Jump to: navigation, search Name Lone Star I (Q2) Wind Farm Facility Lone Star I (Q2) Sector Wind energy Facility Type Commercial Scale Wind Facility Status In...

  4. Lone Star I (Q3) Wind Farm | Open Energy Information

    Open Energy Info (EERE)

    Q3) Wind Farm Jump to: navigation, search Name Lone Star I (Q3) Wind Farm Facility Lone Star I (Q3) Sector Wind energy Facility Type Commercial Scale Wind Facility Status In...

  5. Lone Star Wind Alliance LSWA | Open Energy Information

    Open Energy Info (EERE)

    Wind Alliance LSWA Jump to: navigation, search Name: Lone Star Wind Alliance (LSWA) Place: Houston, Texas Sector: Wind energy Product: Texas-based research centres, focusing on...

  6. Lone Star II (1Q08) Wind Farm | Open Energy Information

    Open Energy Info (EERE)

    Wind Farm Jump to: navigation, search Name Lone Star II (1Q08) Wind Farm Facility Lone Star II (1Q08) Sector Wind energy Facility Type Commercial Scale Wind Facility Status In...

  7. Lone Star II (4Q07) Wind Farm | Open Energy Information

    Open Energy Info (EERE)

    Wind Farm Jump to: navigation, search Name Lone Star II (4Q07) Wind Farm Facility Lone Star II (4Q07) Sector Wind energy Facility Type Commercial Scale Wind Facility Status In...

  8. Lone Star I (4Q07) Wind Farm | Open Energy Information

    Open Energy Info (EERE)

    Wind Farm Jump to: navigation, search Name Lone Star I (4Q07) Wind Farm Facility Lone Star I (4Q07) Sector Wind energy Facility Type Commercial Scale Wind Facility Status In...

  9. Lone Star II (2Q08) Wind Farm | Open Energy Information

    Open Energy Info (EERE)

    Wind Farm Jump to: navigation, search Name Lone Star II (2Q08) Wind Farm Facility Lone Star II (2Q08) Sector Wind energy Facility Type Commercial Scale Wind Facility Status In...

  10. HOT GAS LINES IN T TAURI STARS

    SciTech Connect (OSTI)

    Ardila, David R.; Herczeg, Gregory J.; Gregory, Scott G.; Hillenbrand, Lynne A.; Ingleby, Laura; Bergin, Edwin; Bethell, Thomas; Calvet, Nuria; France, Kevin; Brown, Alexander; Edwards, Suzan; Johns-Krull, Christopher; Linsky, Jeffrey L.; Yang, Hao; Valenti, Jeff A.; Abgrall, Herve; Alexander, Richard D.; Brown, Joanna M.; Espaillat, Catherine; Hussain, Gaitee; and others

    2013-07-01

    For Classical T Tauri Stars (CTTSs), the resonance doublets of N V, Si IV, and C IV, as well as the He II 1640 A line, trace hot gas flows and act as diagnostics of the accretion process. In this paper we assemble a large high-resolution, high-sensitivity data set of these lines in CTTSs and Weak T Tauri Stars (WTTSs). The sample comprises 35 stars: 1 Herbig Ae star, 28 CTTSs, and 6 WTTSs. We find that the C IV, Si IV, and N V lines in CTTSs all have similar shapes. We decompose the C IV and He II lines into broad and narrow Gaussian components (BC and NC). The most common (50%) C IV line morphology in CTTSs is that of a low-velocity NC together with a redshifted BC. For CTTSs, a strong BC is the result of the accretion process. The contribution fraction of the NC to the C IV line flux in CTTSs increases with accretion rate, from {approx}20% to up to {approx}80%. The velocity centroids of the BCs and NCs are such that V{sub BC} {approx}> 4 V{sub NC}, consistent with the predictions of the accretion shock model, in at most 12 out of 22 CTTSs. We do not find evidence of the post-shock becoming buried in the stellar photosphere due to the pressure of the accretion flow. The He II CTTSs lines are generally symmetric and narrow, with FWHM and redshifts comparable to those of WTTSs. They are less redshifted than the CTTSs C IV lines, by {approx}10 km s{sup -1}. The amount of flux in the BC of the He II line is small compared to that of the C IV line, and we show that this is consistent with models of the pre-shock column emission. Overall, the observations are consistent with the presence of multiple accretion columns with different densities or with accretion models that predict a slow-moving, low-density region in the periphery of the accretion column. For HN Tau A and RW Aur A, most of the C IV line is blueshifted suggesting that the C IV emission is produced by shocks within outflow jets. In our sample, the Herbig Ae star DX Cha is the only object for which we find a

  11. Missouri Gas Energy (MGE)- Home Performance with ENERGY STAR

    Broader source: Energy.gov [DOE]

    Missouri Gas Energy (MGE) offers rebates to its residential customers towards the cost of an ENERGY STAR Home Energy Assessment and a portion of the installed efficiency improvements. Home...

  12. GAS EMISSION FROM DEBRIS DISKS AROUND A AND F STARS

    SciTech Connect (OSTI)

    Zagorovsky, Kyryl; Brandeker, Alexis; Wu Yanqin E-mail: alexis@astro.su.s

    2010-09-01

    Gas has been detected in a number of debris disk systems. This gas may have arisen from grain sublimation or grain photodesorption. It interacts with the surrounding dust grains through a number of charge and heat exchanges. Studying the chemical composition and physical state of this gas can therefore reveal much about the dust component in these debris disks. We have produced a new code, ONTARIO, to address gas emission from dusty gas-poor disks around A-F stars. This code computes the gas ionization and thermal balance self-consistently, with particular care taken of heating/cooling mechanisms. Line emission spectra are then produced for each species (up to zinc) by statistical equilibrium calculations of the atomic/ionic energy levels. For parameters that resemble the observed {beta} Pictoris gas disk, we find that the gas is primarily heated by photoelectric emission from dust grains, and primarily cooled through the C II 157.7 {mu}m line emission. The gas can be heated to a temperature that is warmer than that of the dust and may in some cases reach temperature for thermal escape. The dominant cooling line, C II 157.7 {mu}m, should be detectable by Herschel in these disks, while the O I 63.2 {mu}m line will be too faint. We also study the dependence of the cooling line fluxes on a variety of disk parameters, in light of the much improved sensitivity to thermal line emission in the mid/far-infrared and at submillimeter wavelengths provided by, in particular, Herschel, SOFIA, and ALMA. These new instruments will yield much new information about dusty debris disks.

  13. STAR

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

    STAR Basics The basics of STAR computing at PDSF. Read More » Local STAR Libraries These are the STAR libraries built locally at PDSF. Read More » STAR Test Environment The instructions describe how to set up the STAR environment independent of the production environment. Read More » Data Management STAR data transfer, HPSS usage, databases and job scheduler. Read More » File Systems STAR has space on 7 elizas... Read More » Shifter image of STAR SL13a WORK-IN PROGRESS A demonstrator STAR

  14. THE EGNoG SURVEY: MOLECULAR GAS IN INTERMEDIATE-REDSHIFT STAR-FORMING GALAXIES

    SciTech Connect (OSTI)

    Bauermeister, A.; Blitz, L.; Wright, M.; Bolatto, A.; Teuben, P.; Bureau, M.; Leroy, A.; Ostriker, E.; Wong, T.

    2013-05-10

    We present the Evolution of molecular Gas in Normal Galaxies (EGNoG) survey, an observational study of molecular gas in 31 star-forming galaxies from z = 0.05 to z = 0.5, with stellar masses of (4-30) Multiplication-Sign 10{sup 10} M{sub Sun} and star formation rates of 4-100 M{sub Sun} yr{sup -1}. This survey probes a relatively un-observed redshift range in which the molecular gas content of galaxies is expected to have evolved significantly. To trace the molecular gas in the EGNoG galaxies, we observe the CO(J = 1 {yields} 0) and CO(J = 3 {yields} 2) rotational lines using the Combined Array for Research in Millimeter-wave Astronomy (CARMA). We detect 24 of 31 galaxies and present resolved maps of 10 galaxies in the lower redshift portion of the survey. We use a bimodal prescription for the CO to molecular gas conversion factor, based on specific star formation rate, and compare the EGNoG galaxies to a large sample of galaxies assembled from the literature. We find an average molecular gas depletion time of 0.76 {+-} 0.54 Gyr for normal galaxies and 0.06 {+-} 0.04 Gyr for starburst galaxies. We calculate an average molecular gas fraction of 7%-20% at the intermediate redshifts probed by the EGNoG survey. By expressing the molecular gas fraction in terms of the specific star formation rate and molecular gas depletion time (using typical values), we also calculate the expected evolution of the molecular gas fraction with redshift. The predicted behavior agrees well with the significant evolution observed from z {approx} 2.5 to today.

  15. From gas to stars in energetic environments: dense gas clumps in the 30 Doradus region within the Large Magellanic Cloud

    SciTech Connect (OSTI)

    Anderson, Crystal N.; Meier, David S.; Ott, Jrgen; Hughes, Annie; Wong, Tony; Looney, Leslie; Henkel, Christian; Chen, Rosie; Indebetouw, Remy; Muller, Erik; Pineda, Jorge L.; Seale, Jonathan

    2014-09-20

    We present parsec-scale interferometric maps of HCN(1-0) and HCO{sup +}(1-0) emission from dense gas in the star-forming region 30 Doradus, obtained using the Australia Telescope Compact Array. This extreme star-forming region, located in the Large Magellanic Cloud (LMC), is characterized by a very intense ultraviolet ionizing radiation field and sub-solar metallicity, both of which are expected to impact molecular cloud structure. We detect 13 bright, dense clumps within the 30 Doradus-10 giant molecular cloud. Some of the clumps are aligned along a filamentary structure with a characteristic spacing that is consistent with formation via varicose fluid instability. Our analysis shows that the filament is gravitationally unstable and collapsing to form stars. There is a good correlation between HCO{sup +} emission in the filament and signatures of recent star formation activity including H{sub 2}O masers and young stellar objects (YSOs). YSOs seem to continue along the same direction of the filament toward the massive compact star cluster R136 in the southwest. We present detailed comparisons of clump properties (masses, linewidths, and sizes) in 30Dor-10 to those in other star forming regions of the LMC (N159, N113, N105, and N44). Our analysis shows that the 30Dor-10 clumps have similar masses but wider linewidths and similar HCN/HCO{sup +} (1-0) line ratios as clumps detected in other LMC star-forming regions. Our results suggest that the dense molecular gas clumps in the interior of 30Dor-10 are well shielded against the intense ionizing field that is present in the 30 Doradus region.

  16. THE GAS INFLOW AND OUTFLOW RATE IN STAR-FORMING GALAXIES AT z ? 1.4

    SciTech Connect (OSTI)

    Yabe, Kiyoto; Ohta, Kouji; Iwamuro, Fumihide; Akiyama, Masayuki; Tamura, Naoyuki; Yuma, Suraphong; Dalton, Gavin; Lewis, Ian

    2015-01-01

    We try to constrain the gas inflow and outflow rate of star-forming galaxies at z ? 1.4 by employing a simple analytic model for the chemical evolution of galaxies. The sample is constructed based on a large near-infrared spectroscopic sample observed with Subaru/FMOS. The gas-phase metallicity is measured from the [N II]?6584/H? emission line ratio and the gas mass is derived from the extinction corrected H? luminosity by assuming the Kennicutt-Schmidt law. We constrain the inflow and outflow rate from the least-?{sup 2} fittings of the observed gas-mass fraction, stellar mass, and metallicity with the analytic model. The joint ?{sup 2} fitting shows that the best-fit inflow rate is ?1.8 and the outflow rate is ?0.6 in units of star-formation rate. By applying the same analysis to the previous studies at z ? 0 and z ? 2.2, it is shown that both the inflow and outflow rates decrease with decreasing redshift, which implies the higher activity of gas flow process at higher redshift. The decreasing trend of the inflow rate from z ? 2.2 to z ? 0 agrees with that seen in previous observational works with different methods, though the absolute value is generally larger than in previous works. The outflow rate and its evolution from z ? 2.2 to z ? 0 obtained in this work agree well with the independent estimations in previous observational works.

  17. CARMA LARGE AREA STAR FORMATION SURVEY: STRUCTURE AND KINEMATICS OF DENSE GAS IN SERPENS MAIN

    SciTech Connect (OSTI)

    Lee, Katherine I.; Storm, Shaye; Mundy, Lee G.; Teuben, Peter; Pound, Marc W.; Salter, Demerese M.; Chen, Che-Yu; Fernndez-Lpez, Manuel; Looney, Leslie W.; Segura-Cox, Dominique; Rosolowsky, Erik; Arce, Hctor G.; Plunkett, Adele L.; Ostriker, Eve C.; Shirley, Yancy L.; Kwon, Woojin; Kauffmann, Jens; Tobin, John J.; Volgenau, N. H.; Tassis, Konstantinos; and others

    2014-12-20

    We present observations of N{sub 2}H{sup +} (J = 1 ? 0), HCO{sup +} (J = 1 ? 0), and HCN (J = 1 ? 0) toward the Serpens Main molecular cloud from the CARMA Large Area Star Formation Survey (CLASSy). We mapped 150 arcmin{sup 2} of Serpens Main with an angular resolution of ?7''. The gas emission is concentrated in two subclusters (the NW and SE subclusters). The SE subcluster has more prominent filamentary structures and more complicated kinematics compared to the NW subcluster. The majority of gas in the two subclusters has subsonic to sonic velocity dispersions. We applied a dendrogram technique with N{sub 2}H{sup +}(1-0) to study the gas structures; the SE subcluster has a higher degree of hierarchy than the NW subcluster. Combining the dendrogram and line fitting analyses reveals two distinct relations: a flat relation between nonthermal velocity dispersion and size, and a positive correlation between variation in velocity centroids and size. The two relations imply a characteristic depth of 0.15 pc for the cloud. Furthermore, we have identified six filaments in the SE subcluster. These filaments have lengths of ?0.2 pc and widths of ?0.03 pc, which is smaller than a characteristic width of 0.1 pc suggested by Herschel observations. The filaments can be classified into two types based on their properties. The first type, located in the northeast of the SE subcluster, has larger velocity gradients, smaller masses, and nearly critical mass-per-unit-length ratios. The other type, located in the southwest of the SE subcluster, has the opposite properties. Several YSOs are formed along two filaments which have supercritical mass per unit length ratios, while filaments with nearly critical mass-per-unit-length ratios are not associated with YSOs, suggesting that stars are formed on gravitationally unstable filaments.

  18. CORRELATION BETWEEN ENVIRONMENT AND GAS METALLICITY FOR STAR-FORMING GALAXIES IN THE MAIN GALAXY SAMPLE OF SDSS DR7

    SciTech Connect (OSTI)

    Deng Xinfa

    2011-05-15

    Using two volume-limited samples of the Main Galaxy sample of the Sloan Digital Sky Survey Data Release 7 with luminosities of -20.5 {<=} M{sub r} {<=} -18.5 and -22.5 {<=} M{sub r} {<=} -20.5, respectively, I explore the correlation between environment and gas metallicity for star-forming galaxies. Overall, results indicate that galaxies in the lowest density regime preferentially have lower gas metallicity than galaxies in the densest regimes, and that the correlation between environment and gas metallicity is fundamental.

  19. Connecting CO intensity mapping to molecular gas and star formation in the epoch of galaxy assembly

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

    Li, Tony Y.; Wechsler, Risa H.; Devaraj, Kiruthika; Church, Sarah E.

    2016-01-29

    Intensity mapping, which images a single spectral line from unresolved galaxies across cosmological volumes, is a promising technique for probing the early universe. Here we present predictions for the intensity map and power spectrum of the CO(1–0) line from galaxies atmore » $$z\\sim 2.4$$–2.8, based on a parameterized model for the galaxy–halo connection, and demonstrate the extent to which properties of high-redshift galaxies can be directly inferred from such observations. We find that our fiducial prediction should be detectable by a realistic experiment. Motivated by significant modeling uncertainties, we demonstrate the effect on the power spectrum of varying each parameter in our model. Using simulated observations, we infer constraints on our model parameter space with an MCMC procedure, and show corresponding constraints on the $${L}_{\\mathrm{IR}}$$–$${L}_{\\mathrm{CO}}$$ relation and the CO luminosity function. These constraints would be complementary to current high-redshift galaxy observations, which can detect the brightest galaxies but not complete samples from the faint end of the luminosity function. Furthermore, by probing these populations in aggregate, CO intensity mapping could be a valuable tool for probing molecular gas and its relation to star formation in high-redshift galaxies.« less

  20. MOLECULAR GAS, CO, AND STAR FORMATION IN GALAXIES: EMERGENT EMPIRICAL RELATIONS, FEEDBACK, AND THE EVOLUTION OF VERY GAS-RICH SYSTEMS

    SciTech Connect (OSTI)

    Pelupessy, Federico I. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Papadopoulos, Padelis P. [Argelander Institut fuer Astronomie, Auf dem Huegel 71, D-53121 Bonn (Germany)

    2009-12-20

    We use time-varying models of the coupled evolution of the H I, H{sub 2} gas phases and stars in galaxy-sized numerical simulations to (1) test for the emergence of the Kennicutt-Schmidt (K-S) and the H{sub 2}-pressure relation, (2) explore a realistic H{sub 2}-regulated star formation recipe which brings forth a neglected and potentially significant SF-regulating factor, and (3) go beyond typical galactic environments (for which these galactic empirical relations are deduced) to explore the early evolution of very gas-rich galaxies. In this work, we model low-mass galaxies (M{sub baryon} <= 10{sup 9} M{sub sun}), while incorporating an independent treatment of CO formation and destruction, the most important tracer molecule of H{sub 2} in galaxies, along with that for the H{sub 2} gas itself. We find that both the K-S and the H{sub 2}-pressure empirical relations can robustly emerge in galaxies after a dynamic equilibrium sets in between the various interstellar medium (ISM) states, the stellar component and its feedback (T approx> 1 Gyr). The only significant dependence of these relations seems to be for the CO-derived (and thus directly observable) ones, which show a strong dependence on the ISM metallicity. The H{sub 2}-regulated star formation recipe successfully reproduces the morphological and quantitative aspects of previous numerical models while doing away with the star formation efficiency parameter. Most of the H I -> H{sub 2} mass exchange is found taking place under highly non-equilibrium conditions necessitating a time-dependent treatment even in typical ISM environments. Our dynamic models indicate that the CO molecule can be a poor, nonlinear, H{sub 2} gas tracer. Finally, for early evolutionary stages (T approx< 0.4 Gyr), we find significant and systematic deviations of the true star formation from that expected from the K-S relation, which are especially pronounced and prolonged for metal-poor systems. The largest such deviations occur for the

  1. HST-COS SPECTROSCOPY OF THE COOLING FLOW IN A1795EVIDENCE FOR INEFFICIENT STAR FORMATION IN CONDENSING INTRACLUSTER GAS

    SciTech Connect (OSTI)

    McDonald, Michael; Ehlert, Steven; Roediger, Joel; Veilleux, Sylvain

    2014-08-20

    We present far-UV spectroscopy from the Cosmic Origins Spectrograph on the Hubble Space Telescope of a cool, star-forming filament in the core of A1795. These data, which span 1025 < ?{sub rest} < 1700, allow for the simultaneous modeling of the young stellar populations and the intermediate-temperature (10{sup 5.5}K) gas in this filament, which is far removed (?30kpc) from the direct influence of the central active galactic nucleus. Using a combination of UV absorption line indices and stellar population synthesis modeling, we find evidence for ongoing star formation, with the youngest stars having ages of 7.5{sub ?2.0}{sup +2.5}Myr and metallicities of 0.4{sub ?0.1}{sup +0.2} Z {sub ?}. The latter is consistent with the local metallicity of the intracluster medium. We detect the O VI?1038 line, measuring a flux of f {sub O} {sub VI,} {sub 1038} = 4.0 0.9 10{sup 17} erg s{sup 1} cm{sup 2}. The O VI?1032 line is redshifted such that it is coincident with a strong Galactic H{sub 2} absorption feature, and is not detected. The measured O VI?1038 flux corresponds to a cooling rate of 0.85 0.2 (stat) 0.15 (sys) M {sub ?} yr{sup 1} at ?10{sup 5.5}K, assuming that the cooling proceeds isochorically, which is consistent with the classical X-ray luminosity-derived cooling rate in the same region. We measure a star formation rate of 0.11 0.02 M {sub ?} yr{sup 1} from the UV continuum, suggesting that star formation is proceeding at 13{sub ?2}{sup +3}% efficiency in this filament. We propose that this inefficient star formation represents a significant contribution to the larger-scale cooling flow problem.

  2. Molecular gas heating mechanisms, and star formation feedback in merger/starbursts: NGC 6240 and Arp 193 as case studies

    SciTech Connect (OSTI)

    Papadopoulos, Padelis P.; Zhang, Zhi-Yu; Weiss, Axel; Van der Werf, Paul; Israel, F. P.; Greve, T. R.; Isaak, Kate G.; Gao, Y. E-mail: zyzhang@pmo.ac.cn E-mail: aweiss@mpifr-bonn.mpg.de E-mail: israel@strw.leidenuniv.nl E-mail: kisaak@rssd.esa.int

    2014-06-20

    We used the SPIRE/FTS instrument aboard the Herschel Space Observatory to obtain the Spectral Line Energy Distributions (SLEDs) of CO from J = 4-3 to J = 13-12 of Arp 193 and NGC 6240, two classical merger/starbursts selected from our molecular line survey of local Luminous Infrared Galaxies (L {sub IR} ≥ 10{sup 11} L {sub ☉}). The high-J CO SLEDs are then combined with ground-based low-J CO, {sup 13}CO, HCN, HCO{sup +}, CS line data and used to probe the thermal and dynamical states of their large molecular gas reservoirs. We find the two CO SLEDs strongly diverging from J = 4-3 onward, with NGC 6240 having a much higher CO line excitation than Arp 193, despite their similar low-J CO SLEDs and L {sub FIR}/L {sub CO,} {sub 1} {sub –0}, L {sub HCN}/L {sub CO} (J = 1-0) ratios (proxies of star formation efficiency and dense gas mass fraction). In Arp 193, one of the three most extreme starbursts in the local universe, the molecular SLEDs indicate a small amount (∼5%-15%) of dense gas (n ≥ 10{sup 4} cm{sup –3}) unlike NGC 6240 where most of the molecular gas (∼60%-70%) is dense (n ∼ (10{sup 4}-10{sup 5}) cm{sup –3}). Strong star-formation feedback can drive this disparity in their dense gas mass fractions, and also induce extreme thermal and dynamical states for the molecular gas. In NGC 6240, and to a lesser degree in Arp 193, we find large molecular gas masses whose thermal states cannot be maintained by FUV photons from Photon-Dominated Regions. We argue that this may happen often in metal-rich merger/starbursts, strongly altering the initial conditions of star formation. ALMA can now directly probe these conditions across cosmic epoch, and even probe their deeply dust-enshrouded outcome, the stellar initial mass function averaged over galactic evolution.

  3. Ionized gas kinematics at high resolution. IV. Star formation and a rotating core in the Medusa (NGC 4194)

    SciTech Connect (OSTI)

    Beck, Sara C.; Lacy, John; Turner, Jean; Greathouse, Thomas; Neff, Susan

    2014-05-20

    NGC 4194 is a post-merger starburst known as The Medusa for its striking tidal features. We present here a detailed study of the structure and kinematics of ionized gas in the central 0.65 kpc of the Medusa. The data include radio continuum maps with resolution up to 0.''18 (35 pc) and a 12.8 ?m [Ne II] data cube with spectral resolution ?4 km s{sup 1}: the first high-resolution, extinction-free observations of this remarkable object. The ionized gas has the kinematic signature of a core in solid-body rotation. The starburst has formed a complex of bright compact H II regions, probably excited by deeply embedded super star clusters, but none of these sources is a convincing candidate for a Galactic nucleus. The nuclei of the merger partners that created the Medusa have not yet been identified.

  4. VALIDATION OF THE EQUILIBRIUM MODEL FOR GALAXY EVOLUTION TO z ∼ 3 THROUGH MOLECULAR GAS AND DUST OBSERVATIONS OF LENSED STAR-FORMING GALAXIES

    SciTech Connect (OSTI)

    Saintonge, Amélie; Lutz, Dieter; Genzel, Reinhard; Tacconi, Linda J.; Berta, Stefano; Förster Schreiber, Natascha M.; Poglitsch, Albrecht; Sturm, Eckhard; Wuyts, Eva; Wuyts, Stijn; Magnelli, Benjamin; Nordon, Raanan; Baker, Andrew J.; Bandara, Kaushala

    2013-11-20

    We combine IRAM Plateau de Bure Interferometer and Herschel PACS and SPIRE measurements to study the dust and gas contents of high-redshift star-forming galaxies. We present new observations for a sample of 17 lensed galaxies at z = 1.4-3.1, which allow us to directly probe the cold interstellar medium of normal star-forming galaxies with stellar masses of ∼10{sup 10} M{sub ☉}, a regime otherwise not (yet) accessible by individual detections in Herschel and molecular gas studies. The lensed galaxies are combined with reference samples of submillimeter and normal z ∼ 1-2 star-forming galaxies with similar far-infrared photometry to study the gas and dust properties of galaxies in the SFR-M{sub *}-redshift parameter space. The mean gas depletion timescale of main-sequence (MS) galaxies at z > 2 is measured to be only ∼450 Myr, a factor of ∼1.5 (∼5) shorter than at z = 1 (z = 0), in agreement with a (1 + z){sup –1} scaling. The mean gas mass fraction at z = 2.8 is 40% ± 15% (44% after incompleteness correction), suggesting a flattening or even a reversal of the trend of increasing gas fractions with redshift recently observed up to z ∼ 2. The depletion timescale and gas fractions of the z > 2 normal star-forming galaxies can be explained under the 'equilibrium model' for galaxy evolution, in which the gas reservoir of galaxies is the primary driver of the redshift evolution of specific star formation rates. Due to their high star formation efficiencies and low metallicities, the z > 2 lensed galaxies have warm dust despite being located on the star formation MS. At fixed metallicity, they also have a gas-to-dust ratio 1.7 times larger than observed locally when using the same standard techniques, suggesting that applying the local calibration of the δ{sub GDR}-metallicity relation to infer the molecular gas mass of high-redshift galaxies may lead to systematic differences with CO-based estimates.

  5. Calloway Makes Sweet 16, Lone Oak Competes in DOE National Science Bowl |

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Department of Energy Calloway Makes Sweet 16, Lone Oak Competes in DOE National Science Bowl Calloway Makes Sweet 16, Lone Oak Competes in DOE National Science Bowl April 29, 2014 - 2:43pm Addthis Calloway County High School's Mia Beth Morehead, coach, Landon Fike, Cody Bergman, Sam Morehead, Josh Betts, and Hudson Elliott from Murray, Kentucky, pose for a team photo during the 2014 National Science Bowl competition, Thursday, April 24, 2014, in Washington, DC. Calloway County High School's

  6. Beyond the Lone-Pair Model for Structurally Distorted Metal Oxides

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

    Beyond the Lone-Pair Model for Structurally Distorted Metal Oxides Print "Ferroelectricity," by analogy to ferromagnetism, is defined as the presence of spontaneous electrical polarization in a material, often arising from distortions in the material's crystal structure. In oxides of the metals lead and bismuth, such distortions were for many years attributed to the existence of "lone pair" electrons: pairs of chemically inert, nonbonding valence electrons in hybrid orbitals

  7. Beyond the Lone-Pair Model for Structurally Distorted Metal Oxides

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

    Beyond the Lone-Pair Model for Structurally Distorted Metal Oxides Beyond the Lone-Pair Model for Structurally Distorted Metal Oxides Print Wednesday, 28 February 2007 00:00 "Ferroelectricity," by analogy to ferromagnetism, is defined as the presence of spontaneous electrical polarization in a material, often arising from distortions in the material's crystal structure. In oxides of the metals lead and bismuth, such distortions were for many years attributed to the existence of

  8. Beyond the Lone-Pair Model for Structurally Distorted Metal Oxides

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

    Beyond the Lone-Pair Model for Structurally Distorted Metal Oxides Print "Ferroelectricity," by analogy to ferromagnetism, is defined as the presence of spontaneous electrical polarization in a material, often arising from distortions in the material's crystal structure. In oxides of the metals lead and bismuth, such distortions were for many years attributed to the existence of "lone pair" electrons: pairs of chemically inert, nonbonding valence electrons in hybrid orbitals

  9. THE JAMES CLERK MAXWELL TELESCOPE NEARBY GALAXIES LEGACY SURVEY. II. WARM MOLECULAR GAS AND STAR FORMATION IN THREE FIELD SPIRAL GALAXIES

    SciTech Connect (OSTI)

    Warren, B. E.; Wilson, C. D.; Sinukoff, E.; Israel, F. P.; Van der Werf, P. P.; Serjeant, S.; Bendo, G. J.; Clements, D. L.; Brinks, E.; Irwin, J. A.; Knapen, J. H.; Leech, J.; Tan, B. K.; Matthews, H. E.; Muehle, S.; Mortimer, A. M. J.; Petitpas, G.; Spekkens, K.; Tilanus, R. P. J.; Usero, A. E-mail: wilson@physics.mcmaster.c E-mail: israel@strw.leidenuniv.n

    2010-05-01

    We present the results of large-area {sup 12}CO J = 3-2 emission mapping of three nearby field galaxies, NGC 628, NGC 3521, and NGC 3627, completed at the James Clerk Maxwell Telescope as part of the Nearby Galaxies Legacy Survey. These galaxies all have moderate to strong {sup 12}CO J = 3-2 detections over large areas of the fields observed by the survey, showing resolved structure and dynamics in their warm/dense molecular gas disks. All three galaxies were part of the Spitzer Infrared Nearby Galaxies Survey sample, and as such have excellent published multiwavelength ancillary data. These data sets allow us to examine the star formation properties, gas content, and dynamics of these galaxies on sub-kiloparsec scales. We find that the global gas depletion time for dense/warm molecular gas in these galaxies is consistent with other results for nearby spiral galaxies, indicating this may be independent of galaxy properties such as structures, gas compositions, and environments. Similar to the results from The H I Nearby Galaxy Survey, we do not see a correlation of the star formation efficiency with the gas surface density consistent with the Schmidt-Kennicutt law. Finally, we find that the star formation efficiency of the dense molecular gas traced by {sup 12}CO J = 3-2 is potentially flat or slightly declining as a function of molecular gas density, the {sup 12}CO J = 3-2/J = 1-0 ratio (in contrast to the correlation found in a previous study into the starburst galaxy M83), and the fraction of total gas in molecular form.

  10. CARMA Large Area Star Formation Survey: project overview with analysis of dense gas structure and kinematics in Barnard 1

    SciTech Connect (OSTI)

    Storm, Shaye; Mundy, Lee G.; Lee, Katherine I.; Teuben, Peter; Pound, Marc W.; Salter, Demerese M.; Chen, Che-Yu; Gong, Hao; Fernndez-Lpez, Manuel; Looney, Leslie W.; Segura-Cox, Dominique M.; Rosolowsky, Erik; Arce, Hctor G.; Plunkett, Adele L.; Ostriker, Eve C.; Volgenau, Nikolaus H.; Shirley, Yancy L.; Tobin, John J.; Kwon, Woojin; Isella, Andrea; and others

    2014-10-20

    We present details of the CARMA Large Area Star Formation Survey (CLASSy), while focusing on observations of Barnard 1. CLASSy is a CARMA Key Project that spectrally imaged N{sub 2}H{sup +}, HCO{sup +}, and HCN (J = 1 ? 0 transitions) across over 800 square arcminutes of the Perseus and Serpens Molecular Clouds. The observations have angular resolution near 7'' and spectral resolution near 0.16 km s{sup 1}. We imaged ?150 square arcminutes of Barnard 1, focusing on the main core, and the B1 Ridge and clumps to its southwest. N{sub 2}H{sup +} shows the strongest emission, with morphology similar to cool dust in the region, while HCO{sup +} and HCN trace several molecular outflows from a collection of protostars in the main core. We identify a range of kinematic complexity, with N{sub 2}H{sup +} velocity dispersions ranging from ?0.05 to 0.50 km s{sup 1} across the field. Simultaneous continuum mapping at 3 mm reveals six compact object detections, three of which are new detections. A new, non-binary dendrogram algorithm is used to analyze dense gas structures in the N{sub 2}H{sup +} position-position-velocity (PPV) cube. The projected sizes of dendrogram-identified structures range from about 0.01 to 0.34 pc. Size-linewidth relations using those structures show that non-thermal line-of-sight velocity dispersion varies weakly with projected size, while rms variation in the centroid velocity rises steeply with projected size. Comparing these relations, we propose that all dense gas structures in Barnard 1 have comparable depths into the sky, around 0.1-0.2 pc; this suggests that overdense, parsec-scale regions within molecular clouds are better described as flattened structures rather than spherical collections of gas. Science-ready PPV cubes for Barnard 1 molecular emission are available for download.

  11. Early science with the large millimeter telescope: exploring the effect of AGN activity on the relationships between molecular gas, dust, and star formation

    SciTech Connect (OSTI)

    Kirkpatrick, Allison; Pope, Alexandra; Calzetti, Daniela; Narayanan, Gopal; Schloerb, F. Peter; Yun, Min S.; Aretxaga, Itziar; Montaa, Alfredo; Vega, Olga; Armus, Lee; Helou, George; Shi, Yong

    2014-12-01

    The molecular gas, H{sub 2}, that fuels star formation in galaxies is difficult to observe directly. As such, the ratio of L {sub IR} to L{sub CO}{sup ?} is an observational estimate of the star formation rate compared with the amount of molecular gas available to form stars, which is related to the star formation efficiency and the inverse of the gas consumption timescale. We test what effect an IR luminous active galactic nucleus (AGN) has on the ratio L{sub IR}/L{sub CO}{sup ?} in a sample of 24 intermediate redshift galaxies from the 5 mJy Unbiased Spitzer Extragalactic Survey (5MUSES). We obtain new CO(1-0) observations with the Redshift Search Receiver on the Large Millimeter Telescope. We diagnose the presence and strength of an AGN using Spitzer IRS spectroscopy. We find that removing the AGN contribution to L{sub IR}{sup tot} results in a mean L{sub IR}{sup SF}/L{sub CO}{sup ?} for our entire sample consistent with the mean L{sub IR}/L{sub CO}{sup ?} derived for a large sample of star forming galaxies from z ? 0-3. We also include in our comparison the relative amount of polycyclic aromatic hydrocarbon emission for our sample and a literature sample of local and high-redshift ultra luminous infrared galaxies and find a consistent trend between L{sub 6.2}/L{sub IR}{sup SF} and L{sub IR}{sup SF}/L{sub CO}{sup ?}, such that small dust grain emission decreases with increasing L{sub IR}{sup SF}/L{sub CO}{sup ?} for both local and high-redshift dusty galaxies.

  12. THREE-DIMENSIONAL GAS DYNAMIC SIMULATION OF THE INTERACTION BETWEEN THE EXOPLANET WASP-12b AND ITS HOST STAR

    SciTech Connect (OSTI)

    Bisikalo, D.; Kaygorodov, P.; Ionov, D.; Shematovich, V.; Lammer, H.; Fossati, L.

    2013-02-10

    Hubble Space Telescope transit observations in the near-UV performed in 2009 made WASP-12b one of the most 'mysterious' exoplanets; the system presents an early ingress, which can be explained by the presence of optically thick matter located ahead of the planet at a distance of {approx}4-5 planet radii. This work follows previous attempts to explain this asymmetry with an exospheric outflow or a bow shock, induced by a planetary magnetic field, and provides a numerical solution of the early ingress, though we did not perform any radiative transfer calculation. We performed pure 3D gas dynamic simulations of the plasma interaction between WASP-12b and its host star and describe the flow pattern in the system. In particular, we show that the overfilling of the planet's Roche lobe leads to a noticeable outflow from the upper atmosphere in the direction of the L{sub 1} and L{sub 2} points. Due to the conservation of the angular momentum, the flow to the L{sub 1} point is deflected in the direction of the planet's orbital motion, while the flow toward L{sub 2} is deflected in the opposite direction, resulting in a non-axisymmetric envelope, surrounding the planet. The supersonic motion of the planet inside the stellar wind leads to the formation of a bow shock with a complex shape. The existence of the bow shock slows down the outflow through the L{sub 1} and L{sub 2} points, allowing us to consider a long-living flow structure that is in the steady state.

  13. A GAS GIANT CIRCUMBINARY PLANET TRANSITING THE F STAR PRIMARY OF THE ECLIPSING BINARY STAR KIC 4862625 AND THE INDEPENDENT DISCOVERY AND CHARACTERIZATION OF THE TWO TRANSITING PLANETS IN THE KEPLER-47 SYSTEM

    SciTech Connect (OSTI)

    Kostov, V. B.; Tsvetanov, Z. I.; McCullough, P. R.; Valenti, J. A.; Hinse, T. C.; Hebrard, G.; Diaz, R. F.; Deleuil, M.

    2013-06-10

    We report the discovery of a transiting, gas giant circumbinary planet orbiting the eclipsing binary KIC 4862625 and describe our independent discovery of the two transiting planets orbiting Kepler-47. We describe a simple and semi-automated procedure for identifying individual transits in light curves and present our follow-up measurements of the two circumbinary systems. For the KIC 4862625 system, the 0.52 {+-} 0.018 R{sub Jupiter} radius planet revolves every {approx}138 days and occults the 1.47 {+-} 0.08 M{sub Sun }, 1.7 {+-} 0.06 R{sub Sun} F8 IV primary star producing aperiodic transits of variable durations commensurate with the configuration of the eclipsing binary star. Our best-fit model indicates the orbit has a semi-major axis of 0.64 AU and is slightly eccentric, e = 0.1. For the Kepler-47 system, we confirm the results of Orosz et al. Modulations in the radial velocity of KIC 4862625A are measured both spectroscopically and photometrically, i.e., via Doppler boosting, and produce similar results.

  14. The relationship between stellar mass, gas metallicity, and star formation rate for H?-selected galaxies at z ? 0.8 from the NewH? survey

    SciTech Connect (OSTI)

    Reyes, Mithi A. de los; Ly, Chun; Lee, Janice C.; Peeples, Molly S.; Feddersen, Jesse; Salim, Samir; Momcheva, Ivelina; Dale, Daniel A.; Ouchi, Masami; Ono, Yoshiaki; Finn, Rose

    2015-02-01

    Using a sample of 299 H?-selected galaxies at z?0.8, we study the relationship between galaxy stellar mass, gas-phase metallicity, and star formation rate (SFR), and compare to previous results. We use deep optical spectra obtained with the IMACS spectrograph at the Magellan telescope to measure strong oxygen lines. We combine these spectra and metallicities with (1) rest-frame UV-to-optical imaging, which allows us to determine stellar masses and dust attenuation corrections, and (2) H? narrowband imaging, which provides a robust measurement of the instantaneous SFR. Our sample spans stellar masses of ?10{sup 9}6 10{sup 11} M{sub ?}, SFRs of 0.4270 M{sub ?} yr{sup ?1}, and metal abundances of 12+log(O/H)?8.39.1 (?0.42.6 Z{sub ?}). The correlations that we find between the H?-based SFR and stellar mass (i.e., the star-forming main sequence) and between the stellar mass and metallicity are both consistent with previous z?1 studies of star-forming galaxies. We then study the relationship between the three properties using various plane-fitting techniques and a curve-fitting projection. In all cases, we exclude strong dependence of the M{sub ?}Z relation on SFR, but are unable to distinguish between moderate and no dependence. Our results are consistent with previous massmetallicitySFR studies. We check whether data set limitations may obscure a strong dependence on the SFR by using mock samples drawn from the Sloan Digital Sky Survey. These experiments reveal that the adopted signal-to-noise ratio cuts may have a significant effect on the measured dependence. Further work is needed to investigate these results, and to test whether a fundamental metallicity relation or a fundamental plane describes star-forming galaxies across cosmic time.

  15. Natural Gas Weekly Update

    Annual Energy Outlook [U.S. Energy Information Administration (EIA)]

    more from the system than they nominate. Other pipeline companies, such as CenterPoint Energy Gas Transmission Company and Southern Star Central Gas Pipeline Corporation, both...

  16. Natural Gas Weekly Update

    Gasoline and Diesel Fuel Update (EIA)

    that had been in place since February 1. Other pipeline companies, such as CenterPoint Energy Gas Transmission Company and Southern Star Central Gas Pipeline Corporation, both...

  17. THE INTERSTELLAR MEDIUM IN DISTANT STAR-FORMING GALAXIES: TURBULENT PRESSURE, FRAGMENTATION, AND CLOUD SCALING RELATIONS IN A DENSE GAS DISK AT z = 2.3

    SciTech Connect (OSTI)

    Swinbank, A. M.; Smail, Ian; Papadopoulos, P. P.; Cox, P.; Krips, M.; Neri, R.; Ivison, R. J.; Thomson, A. P.; Richard, J.; Ebeling, H.

    2011-11-20

    We have used the Institut de Radioastronomie Millimetrique (IRAM) Plateau de Bure Interferometer and the Expanded Very Large Array to obtain a high-resolution map of the CO(6-5) and CO(1-0) emission in the lensed, star-forming galaxy SMM J2135-0102 at z = 2.32. The kinematics of the gas are well described by a model of a rotationally supported disk with an inclination-corrected rotation speed, v{sub rot} = 320 {+-} 25 km s{sup -1}, a ratio of rotational-to-dispersion support of v/{sigma} = 3.5 {+-} 0.2, and a dynamical mass of (6.0 {+-} 0.5) Multiplication-Sign 10{sup 10} M{sub Sun} within a radius of 2.5 kpc. The disk has a Toomre parameter, Q = 0.50 {+-} 0.15, suggesting that the gas will rapidly fragment into massive clumps on scales of L{sub J} {approx} 400 pc. We identify star-forming regions on these scales and show that they are {approx}10 Multiplication-Sign denser than those in quiescent environments in local galaxies, and significantly offset from the local molecular cloud scaling relations (Larson's relations). The large offset compared to local molecular cloud line-width-size scaling relations implies that supersonic turbulence should remain dominant on scales {approx}100 Multiplication-Sign smaller than in the kinematically quiescent interstellar medium (ISM) of the Milky Way, while the molecular gas in SMM J2135 is expected to be {approx}50 Multiplication-Sign denser than that in the Milky Way on all scales. This is most likely due to the high external hydrostatic pressure we measure for the ISM, P{sub tot}/k{sub B} {approx} (2 {+-} 1) Multiplication-Sign 10{sup 7} K cm{sup -3}. In such highly turbulent ISM, the subsonic regions of gravitational collapse (and star formation) will be characterized by much higher critical densities, n{sub crit} > = 10{sup 8} cm{sup -3}, a factor {approx}>1000 Multiplication-Sign more than the quiescent ISM of the Milky Way.

  18. STAR METRICS

    Broader source: Energy.gov [DOE]

    Energy continues to define Phase II of the STAR METRICS program, a collaborative initiative to track Research and Development expenditures and their outcomes. Visit the STAR METRICS website for...

  19. ENERGY STAR

    SciTech Connect (OSTI)

    2011-12-16

    ENERGY STAR is a voluntary labeling and recognition program that seeks to accelerate the adoption of clean and efficient domestic energy technologies.

  20. TRIGGERED STAR FORMATION SURROUNDING WOLF-RAYET STAR HD 211853

    SciTech Connect (OSTI)

    Liu Tie; Wu Yuefang; Zhang Huawei; Qin Shengli

    2012-05-20

    The environment surrounding Wolf-Rayet (W-R) star HD 211853 is studied in molecular, infrared, as well as radio, and H I emission. The molecular ring consists of well-separated cores, which have a volume density of 10{sup 3} cm{sup -3} and kinematic temperature {approx}20 K. Most of the cores are under gravitational collapse due to external pressure from the surrounding ionized gas. From the spectral energy distribution modeling toward the young stellar objects, the sequential star formation is revealed on a large scale in space spreading from the W-R star to the molecular ring. A small-scale sequential star formation is revealed toward core 'A', which harbors a very young star cluster. Triggered star formations are thus suggested. The presence of the photodissociation region, the fragmentation of the molecular ring, the collapse of the cores, and the large-scale sequential star formation indicate that the 'collect and collapse' process functions in this region. The star-forming activities in core 'A' seem to be affected by the 'radiation-driven implosion' process.

  1. DENSE GAS TRACERS AND STAR FORMATION LAWS IN ACTIVE GALAXIES: APEX SURVEY OF HCN J = 4 → 3, HCO{sup +} J = 4 → 3, AND CS J = 7 → 6

    SciTech Connect (OSTI)

    Zhang, Zhi-Yu; Gao, Yu; Zhao, Yinghe; Wang, Junzhi

    2014-04-01

    We report HCN J = 4 → 3, HCO{sup +} J = 4 → 3, and CS J = 7 → 6 observations in 20 nearby star-forming galaxies with the Atacama Pathfinder EXperiment 12 m telescope. Combined with four HCN, three HCO{sup +}, and four CS detections from the literature, we probe the empirical link between the luminosity of molecular gas (L{sub gas}{sup ′}) and that of infrared emission (L {sub IR}), up to the highest gas densities (∼10{sup 6} cm{sup –3}) that have been probed so far. For nearby galaxies with large radii, we measure the IR luminosity within the submillimeter beam size (14''-18'') to match the molecular emission. We find linear slopes for L{sub CS} {sub J=7--6}{sup ′}-L {sub IR} and L{sub HCN} {sub J=4--3}{sup ′}-L {sub IR}, and a slightly super-linear slope for L{sub HCO{sup +}} {sub J=4--3}{sup ′}-L {sub IR}. The correlation of L{sub CS} {sub J=7--6}{sup ′}-L {sub IR} even extends over eight orders of luminosity magnitude down to Galactic dense cores, with a fit of log(L {sub IR}) =1.00(± 0.01) ×log(L{sub CS} {sub J=7--6}{sup ′}) + 4.03(± 0.04). Such linear correlations appear to hold for all densities >10{sup 4} cm{sup –3}, and indicate that star formation rate is not related to the free-fall timescale for dense molecular gas.

  2. STARS no star on Kauai

    SciTech Connect (OSTI)

    Jones, M.

    1993-04-01

    The island of Kuai, home to the Pacific Missile Range Facility, is preparing for the first of a series of Star Wars rocket launches expected to begin early this year. The Strategic Defense Initiative plans 40 launches of the Stategic Target System (STARS) over a 10-year period. The focus of the tests appears to be weapons and sensors designed to combat multiple-warhead ICBMs, which will be banned under the START II Treaty that was signed in January. The focus of this article is to express the dubious value of testing the STARS at a time when their application will not be an anticipated problem.

  3. Questar Gas - Home Builder Gas Appliance Rebate Program | Department...

    Broader source: Energy.gov (indexed) [DOE]

    Administrator Questar Gas Website http:www.thermwise.comwybuilderBuilderRebatesWY.html State Wyoming Program Type Rebate Program Rebate Amount Energy Star Home Certification:...

  4. Questar Gas- Home Builder Gas Appliance Rebate Program

    Broader source: Energy.gov [DOE]

    Questar Gas provides incentives for home builders who incorporate energy efficiency into new construction. Builders can receive whole house rebates for building Energy Star homes (certified by an...

  5. Chameleon stars

    SciTech Connect (OSTI)

    Dzhunushaliev, Vladimir; Folomeev, Vladimir; Singleton, Douglas

    2011-10-15

    We consider a gravitating spherically symmetric configuration consisting of a scalar field nonminimally coupled to ordinary matter in the form of a perfect fluid. For this system we find static, regular, asymptotically flat solutions for both relativistic and nonrelativistic cases. It is shown that the presence of the nonminimal interaction leads to substantial changes both in the radial matter distribution of the star and in the star's total mass. A simple stability test indicates that, for the choice of parameters used in the paper, the solutions are unstable.

  6. Star Power

    SciTech Connect (OSTI)

    2014-10-17

    The U.S. Department of Energy's Princeton Plasma Physics Laboratory has released ''Star Power,'' a new informational video that uses dramatic and beautiful images and thought-provoking interviews to highlight the importance of the Laboratory's research into magnetic fusion.

  7. Star Power

    ScienceCinema (OSTI)

    None

    2014-11-18

    The U.S. Department of Energy's Princeton Plasma Physics Laboratory has released ''Star Power,'' a new informational video that uses dramatic and beautiful images and thought-provoking interviews to highlight the importance of the Laboratory's research into magnetic fusion.

  8. Natural Gas Weekly Update, Printer-Friendly Version

    Annual Energy Outlook [U.S. Energy Information Administration (EIA)]

    that had been in place since February 1. Other pipeline companies, such as CenterPoint Energy Gas Transmission Company and Southern Star Central Gas Pipeline Corporation, both...

  9. Natural Gas Weekly Update, Printer-Friendly Version

    Annual Energy Outlook [U.S. Energy Information Administration (EIA)]

    more from the system than they nominate. Other pipeline companies, such as CenterPoint Energy Gas Transmission Company and Southern Star Central Gas Pipeline Corporation, both...

  10. Star formation relations in nearby molecular clouds

    SciTech Connect (OSTI)

    Evans, Neal J. II; Heiderman, Amanda; Vutisalchavakul, Nalin

    2014-02-20

    We test some ideas for star formation relations against data on local molecular clouds. On a cloud by cloud basis, the relation between the surface density of star formation rate and surface density of gas divided by a free-fall time, calculated from the mean cloud density, shows no significant correlation. If a crossing time is substituted for the free-fall time, there is even less correlation. Within a cloud, the star formation rate volume and surface densities increase rapidly with the corresponding gas densities, faster than predicted by models using the free-fall time defined from the local density. A model in which the star formation rate depends linearly on the mass of gas above a visual extinction of 8 mag describes the data on these clouds, with very low dispersion. The data on regions of very massive star formation, with improved star formation rates based on free-free emission from ionized gas, also agree with this linear relation.

  11. Kepler-424 b: A 'lonely' hot Jupiter that found A companion

    SciTech Connect (OSTI)

    Endl, Michael; Caldwell, Douglas A.; Barclay, Thomas; Huber, Daniel; Havel, Mathieu; Howell, Steve B.; Quintana, Elisa; Isaacson, Howard; Buchhave, Lars A.; Brugamyer, Erik; Robertson, Paul; Cochran, William D.; MacQueen, Phillip J.; Lucas, Phillip; Fischer, Debra; Ciardi, David R.

    2014-11-10

    Hot Jupiter systems provide unique observational constraints for migration models in multiple systems and binaries. We report on the discovery of the Kepler-424 (KOI-214) two-planet system, which consists of a transiting hot Jupiter (Kepler-424b) in a 3.31 day orbit accompanied by a more massive outer companion in an eccentric (e = 0.3) 223 day orbit. The outer giant planet, Kepler-424c, is not detected transiting the host star. The masses of both planets and the orbital parameters for the second planet were determined using precise radial velocity (RV) measurements from the Hobby-Eberly Telescope (HET) and its High Resolution Spectrograph (HRS). In stark contrast to smaller planets, hot Jupiters are predominantly found to be lacking any nearby additional planets; they appear to be {sup l}onely{sup .} This might be a consequence of these systems having a highly dynamical past. The Kepler-424 planetary system has a hot Jupiter in a multiple system, similar to ? Andromedae. We also present our results for Kepler-422 (KOI-22), Kepler-77 (KOI-127), Kepler-43 (KOI-135), and Kepler-423 (KOI-183). These results are based on spectroscopic data collected with the Nordic Optical Telescope (NOT), the Keck 1 telescope, and HET. For all systems, we rule out false positives based on various follow-up observations, confirming the planetary nature of these companions. We performed a comparison with planetary evolutionary models which indicate that these five hot Jupiters have heavy element contents between 20 and 120 M {sub ?}.

  12. OBSERVATIONS OF Arp 220 USING HERSCHEL-SPIRE: AN UNPRECEDENTED VIEW OF THE MOLECULAR GAS IN AN EXTREME STAR FORMATION ENVIRONMENT

    SciTech Connect (OSTI)

    Rangwala, Naseem; Maloney, Philip R.; Glenn, Jason; Kamenetzky, Julia; Wilson, Christine D.; Mentuch, Erin; Schirm, Maximilien R. P.; Rykala, Adam; Isaak, Kate; Baes, Maarten; Bendo, George J.; Boselli, Alessandro; Bradford, Charles M.; Clements, D. L.; Cooray, Asantha; Fulton, Trevor; Imhof, Peter; Madden, Suzanne C.; Sauvage, Marc; and others

    2011-12-10

    We present Herschel Spectral and Photometric Imaging Receiver Fourier Transform Spectrometer (Herschel SPIRE-FTS) observations of Arp 220, a nearby ultra-luminous infrared galaxy. The FTS provides continuous spectral coverage from 190 to 670 {mu}m, a wavelength region that is either very difficult to observe or completely inaccessible from the ground. The spectrum provides a good measurement of the continuum and detection of several molecular and atomic species. We detect luminous CO (J = 4-3 to 13-12) and water rotational transitions with comparable total luminosity {approx}2 Multiplication-Sign 10{sup 8} L{sub Sun }; very high-J transitions of HCN (J = 12-11 to 17-16) in absorption; strong absorption features of rare species such as OH{sup +}, H{sub 2}O{sup +}, and HF; and atomic lines of [C I] and [N II]. The modeling of the continuum shows that the dust is warm, with T = 66 K, and has an unusually large optical depth, with {tau}{sub dust} {approx} 5 at 100 {mu}m. The total far-infrared luminosity of Arp 220 is L{sub FIR} {approx} 2 Multiplication-Sign 10{sup 12} L{sub Sun }. Non-LTE modeling of the extinction corrected CO rotational transitions shows that the spectral line energy distribution of CO is fit well by two temperature components: cold molecular gas at T {approx} 50 K and warm molecular gas at T {approx} 1350{sup +280}{sub -100} K (the inferred temperatures are much lower if CO line fluxes are not corrected for dust extinction). These two components are not in pressure equilibrium. The mass of the warm gas is 10% of the cold gas, but it dominates the CO luminosity. The ratio of total CO luminosity to the total FIR luminosity is L{sub CO}/L{sub FIR} {approx} 10{sup -4} (the most luminous lines, such as J = 6-5, have L{sub CO,J=6-5}/L{sub FIR} {approx} 10{sup -5}). The temperature of the warm gas is in excellent agreement with the observations of H{sub 2} rotational lines. At 1350 K, H{sub 2} dominates the cooling ({approx}20 L{sub Sun} M{sup -1}{sub

  13. STAR FORMATION IN NUCLEAR RINGS OF BARRED GALAXIES

    SciTech Connect (OSTI)

    Seo, Woo-Young; Kim, Woong-Tae E-mail: wkim@astro.snu.ac.kr

    2013-06-01

    Nuclear rings in barred galaxies are sites of active star formation. We use hydrodynamic simulations to study the temporal and spatial behavior of star formation occurring in nuclear rings of barred galaxies where radial gas inflows are triggered solely by a bar potential. The star formation recipes include a density threshold, an efficiency, conversion of gas to star particles, and delayed momentum feedback via supernova explosions. We find that the star formation rate (SFR) in a nuclear ring is roughly equal to the mass inflow rate to the ring, while it has a weak dependence on the total gas mass in the ring. The SFR typically exhibits a strong primary burst followed by weak secondary bursts before declining to very small values. The primary burst is associated with the rapid gas infall to the ring due to the bar growth, while the secondary bursts are caused by re-infall of the ejected gas from the primary burst. While star formation in observed rings persists episodically over a few Gyr, the duration of active star formation in our models lasts for only about half of the bar growth time, suggesting that the bar potential alone is unlikely to be responsible for gas supply to the rings. When the SFR is low, most star formation occurs at the contact points between the ring and the dust lanes, leading to an azimuthal age gradient of young star clusters. When the SFR is large, on the other hand, star formation is randomly distributed over the whole circumference of the ring, resulting in no apparent azimuthal age gradient. Since the ring shrinks in size with time, star clusters also exhibit a radial age gradient, with younger clusters found closer to the ring. The cluster mass function is well described by a power law, with a slope depending on the SFR. Giant gas clouds in the rings have supersonic internal velocity dispersions and are gravitationally bound.

  14. TWO-DIMENSIONAL MAPPING OF YOUNG STARS IN THE INNER 180 pc OF NGC 1068: CORRELATION WITH MOLECULAR GAS RING AND STELLAR KINEMATICS

    SciTech Connect (OSTI)

    Storchi-Bergmann, Thaisa; Riffel, Rogerio; Vale, Tiberio Borges; Riffel, Rogemar A.; Diniz, Marlon R.; McGregor, Peter J.

    2012-08-20

    We report the first two-dimensional mapping of the stellar population and non-stellar continua within the inner 180 pc (radius) of NGC 1068 at a spatial resolution of 8 pc, using integral field spectroscopy in the near-infrared. We have applied the technique of spectral synthesis to data obtained with the instrument NIFS and the adaptive optics module ALTAIR at the Gemini North Telescope. Two episodes of recent star formation are found to dominate the stellar population contribution: the first occurred 300 Myr ago, extending over most of the nuclear region; the second occurred just 30 Myr ago, in a ring-like structure at Almost-Equal-To 100 pc from the nucleus, where it is coincident with an expanding ring of H{sub 2} emission. Inside the ring, where a decrease in the stellar velocity dispersion is observed, the stellar population is dominated by the 300 Myr age component. In the inner 35 pc, the oldest age component (age {>=} 2 Gyr) dominates the mass, while the flux is dominated by blackbody components with temperatures in the range 700 K {<=} T {<=} 800 K which we attribute to the dusty torus. We also find some contribution from blackbody and power-law components beyond the nucleus which we attribute to dust emission and scattered light.

  15. Energy Star Appliances

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

    Updates and News ENERGY STAR appliances have been a successful program offer for many BPA utility customers and are expected to continue. However, as ENERGY STAR specifications...

  16. Maintaining STAR - Hanford Site

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

    Getting Started Maintaining STAR VPP CampaignPosters VPP Tools VPP Presentations VPP Awareness VPP Communications VPP Conferences Maintaining STAR Email Email Page | Print Print...

  17. TIME-VARYING DYNAMICAL STAR FORMATION RATE

    SciTech Connect (OSTI)

    Lee, Eve J.; Chang, Philip; Murray, Norman

    2015-02-10

    We present numerical evidence of dynamic star formation in which the accreted stellar mass grows superlinearly with time, roughly as t {sup 2}. We perform simulations of star formation in self-gravitating hydrodynamic and magnetohydrodynamic turbulence that is continuously driven. By turning the self-gravity of the gas in the simulations on or off, we demonstrate that self-gravity is the dominant physical effect setting the mass accretion rate at early times before feedback effects take over, contrary to theories of turbulence-regulated star formation. We find that gravitational collapse steepens the density profile around stars, generating the power-law tail on what is otherwise a lognormal density probability distribution function. Furthermore, we find turbulent velocity profiles to flatten inside collapsing regions, altering the size-line width relation. This local flattening reflects enhancements of turbulent velocity on small scales, as verified by changes to the velocity power spectra. Our results indicate that gas self-gravity dynamically alters both density and velocity structures in clouds, giving rise to a time-varying star formation rate. We find that a substantial fraction of the gas that forms stars arrives via low-density flows, as opposed to accreting through high-density filaments.

  18. The evolutionary tracks of young massive star clusters

    SciTech Connect (OSTI)

    Pfalzner, S.; Steinhausen, M.; Vincke, K.; Menten, K.; Parmentier, G.

    2014-10-20

    Stars mostly form in groups consisting of a few dozen to several ten thousand members. For 30 years, theoretical models have provided a basic concept of how such star clusters form and develop: they originate from the gas and dust of collapsing molecular clouds. The conversion from gas to stars being incomplete, the leftover gas is expelled, leading to cluster expansion and stars becoming unbound. Observationally, a direct confirmation of this process has proved elusive, which is attributed to the diversity of the properties of forming clusters. Here we take into account that the true cluster masses and sizes are masked, initially by the surface density of the background and later by the still present unbound stars. Based on the recent observational finding that in a given star-forming region the star formation efficiency depends on the local density of the gas, we use an analytical approach combined with N-body simulations to reveal evolutionary tracks for young massive clusters covering the first 10 Myr. Just like the Hertzsprung-Russell diagram is a measure for the evolution of stars, these tracks provide equivalent information for clusters. Like stars, massive clusters form and develop faster than their lower-mass counterparts, explaining why so few massive cluster progenitors are found.

  19. STAR FORMATION IN TWO LUMINOUS SPIRAL GALAXIES

    SciTech Connect (OSTI)

    Hunter, Deidre A.; Ashburn, Allison; Wright, Teresa; Elmegreen, Bruce G.; Rubin, Vera C.; Jzsa, Gyula I. G.; Struve, Christian

    2013-10-01

    We examined star formation in two very luminous (M{sub V} = 22 to 23) Sc-type spiral galaxies, NGC 801 and UGC 2885, using ultra-deep H? images. We combine these H? images with UBV and Two-Micron All-Sky Survey JHK images and H I maps to explore the star formation characteristics of disk galaxies at high luminosity. H? traces star formation in these galaxies to 4-6 disk scale lengths, but the lack of detection of H? further out is likely due to the loss of Lyman continuum photons. Considering gravitational instabilities alone, we find that the gas and stars in the outer regions are marginally stable in an average sense, but considering dissipative gas and radial and azimuthal forcing, the outer regions are marginally unstable to forming spiral arms. Star formation is taking place in spiral arms, which are regions of locally higher gas densities. Furthermore, we have traced smooth exponential stellar disks over four magnitudes in V-band surface brightness and 4-6 disk scale lengths, in spite of a highly variable gravitational instability parameter. Thus, gravitational instability thresholds do not seem relevant to the stellar disk. One possibility for creating an exponential disk is that the molecular cloud densities and star formation rates have exponential profiles and this fact forces the stellar disk to build up such a profile. Another possibility is that the stellar disk is continuously adjusted to an exponential shape regardless of the star formation profile, for example, through global dynamical processes that scatter stars. However, such scattering processes are only known to operate in spiral systems, in which case they cannot explain the same dilemma of smooth exponential disks observed in dwarf irregular galaxies.

  20. SUPPRESSION OF STAR FORMATION IN NGC 1266

    SciTech Connect (OSTI)

    Alatalo, Katherine; Lanz, Lauranne; Bitsakis, Theodoros; Appleton, Philip N.; Ogle, Patrick M.; Lacy, Mark; Lonsdale, Carol J.; Nyland, Kristina; Meier, David S.; Cales, Sabrina L.; Chang, Philip; Davis, Timothy A.; De Zeeuw, P. T.; Martn, Sergio

    2015-01-01

    NGC 1266 is a nearby lenticular galaxy that harbors a massive outflow of molecular gas powered by the mechanical energy of an active galactic nucleus (AGN). It has been speculated that such outflows hinder star formation (SF) in their host galaxies, providing a form of feedback to the process of galaxy formation. Previous studies, however, indicated that only jets from extremely rare, high-power quasars or radio galaxies could impart significant feedback on their hosts. Here we present detailed observations of the gas and dust continuum of NGC 1266 at millimeter wavelengths. Our observations show that molecular gas is being driven out of the nuclear region at M-dot {sub out}?110 M{sub ?} yr{sup 1}, of which the vast majority cannot escape the nucleus. Only 2 M {sub ?} yr{sup 1} is actually capable of escaping the galaxy. Most of the molecular gas that remains is very inefficient at forming stars. The far-infrared emission is dominated by an ultra-compact (? 50 pc) source that could either be powered by an AGN or by an ultra-compact starburst. The ratio of the SF surface density (?{sub SFR}) to the gas surface density (?{sub H{sub 2}}) indicates that SF is suppressed by a factor of ?50 compared to normal star-forming galaxies if all gas is forming stars, and ?150 for the outskirt (98%) dense molecular gas if the central region is powered by an ultra-compact starburst. The AGN-driven bulk outflow could account for this extreme suppression by hindering the fragmentation and gravitational collapse necessary to form stars through a process of turbulent injection. This result suggests that even relatively common, low-power AGNs are able to alter the evolution of their host galaxies as their black holes grow onto the M-? relation.

  1. PECO Energy (Gas)- Heating Efficiency Rebate Program

    Broader source: Energy.gov [DOE]

    The PECO Smart Natural Gas Efficiency Upgrade Program offers rebates and incentives to commercial or residential customers that install an ENERGY STAR qualified high-efficiency natural gas furna...

  2. Shooting Star | Open Energy Information

    Open Energy Info (EERE)

    Shooting Star Jump to: navigation, search Name Shooting Star Facility Shooting Star Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner Exelon...

  3. STAR Test Environment

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

    STAR Test Environment STAR Test Environment These instructions describe how to set up the STAR environment independent of the production environment in order to test different installations in $OPTSTAR and $GROUP_DIR. If you want to modify those installations you will need access to the starofl account. Bypass STAR envionment login Edit your ~/.pdsf_setup file changing the STAR_LINUX_SETUP to "use_none" and start a new session. You should not see all the STAR environmental variables

  4. ENERGY STAR Webinar: ENERGY STAR and Green Building Rating Systems...

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

    ENERGY STAR Webinar: ENERGY STAR and Green Building Rating Systems ENERGY STAR Webinar: ENERGY STAR and Green Building Rating Systems June 21, 2016 1:00PM to 2:00PM EDT Hosted by ...

  5. Southwest Gas Corporation- Home Builder Efficiency Rebate Program

    Broader source: Energy.gov [DOE]

    Southwest Gas Corporation offers rebates to home builders constructing ENERGY STAR homes. Builders receive a $200 rebate for ENERGY STAR certified homes, and a $450 rebate for homes that are ENERGY...

  6. ENERGY STAR | Open Energy Information

    Open Energy Info (EERE)

    ENERGY STAR Jump to: navigation, search Logo: ENERGY STAR Name: ENERGY STAR Year Founded: 1992 Website: www.energystar.govindex.cfm?c References: About ENERGY STAR1 Contents 1...

  7. Natural Gas Modernization Clearinghouse Stakeholders | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Initiatives » Natural Gas Modernization Clearinghouse » Natural Gas Modernization Clearinghouse Stakeholders Natural Gas Modernization Clearinghouse Stakeholders Regulators EMATRIX Environmental Protection Agency (EPA) Natural Gas Star program Federal Energy Regulatory Commission (FERC) National Association of Regulatory Utility Commissioners (NARUC) Pipeline and Hazardous Materials Safety Administration (PHMSA) Industry groups American Gas Association (AGA) American Gas Foundation (AGF)

  8. Magnetic fields and galactic star formation rates

    SciTech Connect (OSTI)

    Loo, Sven Van; Tan, Jonathan C.; Falle, Sam A. E. G.

    2015-02-10

    The regulation of galactic-scale star formation rates (SFRs) is a basic problem for theories of galaxy formation and evolution: which processes are responsible for making observed star formation rates so inefficient compared to maximal rates of gas content divided by dynamical timescale? Here we study the effect of magnetic fields of different strengths on the evolution of giant molecular clouds (GMCs) within a kiloparsec patch of a disk galaxy and resolving scales down to ?0.5 pc. Including an empirically motivated prescription for star formation from dense gas (n{sub H}>10{sup 5} cm{sup ?3}) at an efficiency of 2% per local free-fall time, we derive the amount of suppression of star formation by magnetic fields compared to the nonmagnetized case. We find GMC fragmentation, dense clump formation, and SFR can be significantly affected by the inclusion of magnetic fields, especially in our strongest investigated B-field case of 80 ?G. However, our chosen kiloparsec-scale region, extracted from a global galaxy simulation, happens to contain a starbursting cloud complex that is only modestly affected by these magnetic fields and likely requires internal star formation feedback to regulate its SFR.

  9. STAR FORMATION AROUND SUPERGIANT SHELLS IN THE LARGE MAGELLANIC CLOUD

    SciTech Connect (OSTI)

    Book, Laura G.; Chu Youhua; Gruendl, Robert A.; Fukui, Yasuo

    2009-03-15

    We examine the recent star formation associated with four supergiant shells in the Large Magellanic Cloud (LMC): LMC 1, 4, 5, and 6, which have been shown to have simple expanding-shell structures. H II regions and OB associations are used to infer star formation in the last few Myr, while massive young stellar objects reveal the current ongoing star formation. Distributions of ionized H I and molecular components of the interstellar gas are compared with the sites of recent and current star formation to determine whether triggering has taken place. We find that a great majority of the current star formation has occurred in gravitationally unstable regions, and that evidence of triggered star formation is prevalent at both large and local scales.

  10. Baltimore Gas & Electric Company (Electric)- Residential Energy Efficiency Rebate Program

    Broader source: Energy.gov [DOE]

    The Baltimore Gas & Electric Company (BGE) offers rebates for residential customers to improve the energy efficiency of eligible homes. Rebates are available for ENERGY STAR clothes washers,...

  11. UNLEASHING POSITIVE FEEDBACK: LINKING THE RATES OF STAR FORMATION, SUPERMASSIVE BLACK HOLE ACCRETION, AND OUTFLOWS IN DISTANT GALAXIES

    SciTech Connect (OSTI)

    Silk, Joseph

    2013-08-01

    Pressure-regulated star formation is a simple variant on the usual supernova-regulated star formation efficiency that controls the global star formation rate as a function of cold gas content in star-forming galaxies, and accounts for the Schmidt-Kennicutt law in both nearby and distant galaxies. Inclusion of active galactic nucleus (AGN) induced pressure, by jets and/or winds that flow back onto a gas-rich disk, can lead, under some circumstances, to significantly enhanced star formation rates, especially at high redshift and most likely followed by the more widely accepted phase of star formation quenching. Simple expressions are derived that relate supermassive black hole growth, star formation, and outflow rates. The ratios of black hole to spheroid mass and of both black hole accretion and outflow rates to star formation rate are predicted as a function of time. I suggest various tests of the AGN-triggered star formation hypothesis.

  12. Electron lone pair distortion facilitated metal-insulator transition in ?-Pb{sub 0.33}V{sub 2}O{sub 5} nanowires

    SciTech Connect (OSTI)

    Wangoh, L.; Quackenbush, N. F.; Marley, P. M.; Banerjee, S.; Sallis, S.; Fischer, D. A.; Woicik, J. C.; Piper, L. F. J.

    2014-05-05

    The electronic structure of ?-Pb{sub 0.33}V{sub 2}O{sub 5} nanowires has been studied with x-ray photoelectron spectroscopy techniques. The recent synthesis of defect-free ?-Pb{sub 0.33}V{sub 2}O{sub 5} nanowires resulted in the discovery of an abrupt voltage-induced metal insulator transition. First principle calculations predicted an additional V-O-Pb hybridized in-gap state unique to this vanadium bronze playing a significant role in facilitating the transition. We confirm the existence, energetic position, and orbital character of the in-gap state. Moreover, we reveal that this state is a hybridized Pb 6sO 2p antibonding lone pair state resulting from the asymmetric coordination of the Pb{sup 2+} ions.

  13. DIRECT DETECTIONS OF YOUNG STARS IN NEARBY ELLIPTICAL GALAXIES

    SciTech Connect (OSTI)

    Ford, H. Alyson; Bregman, Joel N.

    2013-06-20

    Small amounts of star formation in elliptical galaxies are suggested by several results: surprisingly young ages from optical line indices, cooling X-ray gas, and mid-infrared dust emission. Such star formation has previously been difficult to directly detect, but using ultraviolet Hubble Space Telescope Wide Field Camera 3 imaging, we have identified individual young stars and star clusters in four nearby ellipticals. Ongoing star formation is detected in all galaxies, including three ellipticals that have previously exhibited potential signposts of star-forming conditions (NGC 4636, NGC 4697, and NGC 4374), as well as the typical ''red and dead'' NGC 3379. The current star formation in our closest targets, where we are most complete, is between 2.0 and 9.8 Multiplication-Sign 10{sup -5} M{sub Sun} yr{sup -1}. The star formation history was roughly constant from 0.5 to 1.5 Gyr (at (3-5) Multiplication-Sign 10{sup -4} M{sub Sun} yr{sup -1}), but decreased by a factor of several in the past 0.3 Gyr. Most star clusters have a mass between 10{sup 2} and 10{sup 4} M{sub Sun }. The specific star formation rates of {approx}10{sup -16} yr{sup -1} (at the present day) or {approx}10{sup -14} yr{sup -1} (when averaging over the past Gyr) imply that a fraction 10{sup -8} of the stellar mass is younger than 100 Myr and 10{sup -5} is younger than 1 Gyr, quantifying the level of frosting of recent star formation over the otherwise passive stellar population. There is no obvious correlation between either the presence or spatial distribution of postulated star formation indicators and the star formation we detect.

  14. ULTRA-FAINT DWARF GALAXIES AS A TEST OF EARLY ENRICHMENT AND METALLICITY-DEPENDENT STAR FORMATION

    SciTech Connect (OSTI)

    Tassis, Konstantinos; Gnedin, Nickolay Y.; Kravtsov, Andrey V.

    2012-01-20

    The close relation of star formation with molecular gas indicated by observations and assumed in recent models implies that the efficiency with which galaxies convert their gas into stars depends on gas metallicity. This is because abundance of molecular hydrogen is sensitive to abundance of dust, which catalyzes formation of H{sub 2} and helps to shield it from dissociating radiation. In this study, we point out that in the absence of significant pre-enrichment by Population III stars forming out of zero metallicity gas, such H{sub 2}-based star formation is expected to leave an imprint in the form of bi-modality in the metallicity distribution among dwarf galaxies and in the metallicity distribution of stars within individual galaxies. The bi-modality arises because when gas metallicity (and dust abundance) is low, formation of molecular gas is inefficient, the gas consumption timescale is long, and star formation and metal enrichment proceed slowly. When metallicity reaches a critical threshold value star formation and enrichment accelerate, which leads to rapid increase in both stellar mass and metallicity of galaxies. We demonstrate this process both using a simple analytical model and full cosmological simulations. In contrast, the observed metallicity distributions of dwarf galaxies or stars within them are not bi-modal. We argue that this discrepancy points to substantial early stochastic pre-enrichment by Population III stars to levels Z {approx} 10{sup -2} Z{sub Sun} in dense, star-forming regions of early galaxies.

  15. ENERGY STAR Webinar: ENERGY STAR and Green Building Rating Systems...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    ENERGY STAR and Green Building Rating Systems ENERGY STAR Webinar: ENERGY STAR and Green Building Rating Systems October 13, 2015 2:00PM to 3:00PM EDT Online Hosted by the U.S....

  16. Buildings Energy Data Book: 9.1 ENERGY STAR

    Buildings Energy Data Book [EERE]

    6 Specification Dates for ENERGY STAR-Labeled HVAC and Residential Appliances Heating and Cooling Equipment Dates of updated specification Central AC 1995 2002, 2006, 2009 Air-Source Heat Pumps 1995 2002, 2006, 2009 Oil Furnaces 1995 2006, 2008, 2012, 2013 Gas Furnaces 1995 2006, 2008, 2012, 2013 Programable Thermostats - Gas Boilers 1996 2002 Oil Boilers 1996 2002 Gas-Fired Heat Pumps - Geothermal Heat Pumps 2001 2009, 2011, 2012 Ventilating Fans 2001 2003, 2009, 2012 Ceiling Fans 2001 2003,

  17. Star Biomass | Open Energy Information

    Open Energy Info (EERE)

    Biomass Jump to: navigation, search Name: Star Biomass Place: India Sector: Biomass Product: Plans to set up biomass projects in Rajasthan. References: Star Biomass1 This article...

  18. Carbon Stars | Open Energy Information

    Open Energy Info (EERE)

    Stars Jump to: navigation, search Name: Carbon Stars Place: Netherlands Sector: Services Product: General Financial & Legal Services ( Private family-controlled ) References:...

  19. Quark matter symmetry energy and quark stars

    SciTech Connect (OSTI)

    Chu, Peng-Cheng; Chen, Lie-Wen

    2014-01-10

    We extend the confined-density-dependent-mass (CDDM) model to include isospin dependence of the equivalent quark mass. Within the confined-isospin-density-dependent-mass (CIDDM) model, we study the quark matter symmetry energy, the stability of strange quark matter, and the properties of quark stars. We find that including isospin dependence of the equivalent quark mass can significantly influence the quark matter symmetry energy as well as the properties of strange quark matter and quark stars. While the recently discovered large mass pulsars PSR J1614–2230 and PSR J0348+0432 with masses around 2 M {sub ☉} cannot be quark stars within the CDDM model, they can be well described by quark stars in the CIDDM model. In particular, our results indicate that the two-flavor u-d quark matter symmetry energy should be at least about twice that of a free quark gas or normal quark matter within the conventional Nambu-Jona-Lasinio model in order to describe PSR J1614–2230 and PSR J0348+0432 as quark stars.

  20. Unitil (Gas)- Residential Energy Efficiency Program

    Broader source: Energy.gov [DOE]

    Until also offers rebates for residential new construction through the Natural Gas Energy Star Homes/Residential New Construction Program. To receive rebates, new homes must meet certain energy...

  1. STAR-Running on Carver

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

    STAR-Running on Carver STAR-Running on Carver STAR software has been copied from the usual installation on /common on PDSF to /project/projectdirs/star/common. At this point the installation is simply intended for testing and not all libraries are in place - for now SL10k, SL11b and SL11c are available with root/5.22.00 and a copy of $OPTSTAR and cernlib. An example of how to setup the STAR software on Carver is in /project/projectdirs/star/starenv. To use it simply source star_setup. This

  2. ENERGY STAR Product Rebates

    Broader source: Energy.gov [DOE]

    When mail-in rebates are active, as a general rule, all appliances must be ENERGY STAR rated; however, additional requirements may apply to different types of appliances. Rebate requests must...

  3. Cold Hybrid Star Properties

    SciTech Connect (OSTI)

    Moshfegh, H. R.; Darehmoradi, M.; Mojarrad, M. Ghazanfari

    2011-10-28

    Properties of neutron stars with quark core are investigated. The equation of state of hadronic matter is calculated using Myers and Swiatecki two nucleon interaction within Thomas-Fermi semiclassical approximation (TF). For quark matter we employ The MIT bag model with constant and density dependent bag parameter. With use of the obtained equation of states we have calculated mass-radius relation of such hybrid stars.

  4. STAR Facility Tritium Accountancy

    SciTech Connect (OSTI)

    R. J. Pawelko; J. P. Sharpe; B. J. Denny

    2007-09-01

    The Safety and Tritium Applied Research (STAR) facility has been established to provide a laboratory infrastructure for the fusion community to study tritium science associated with the development of safe fusion energy and other technologies. STAR is a radiological facility with an administrative total tritium inventory limit of 1.5g (14,429 Ci) [1]. Research studies with moderate tritium quantities and various radionuclides are performed in STAR. Successful operation of the STAR facility requires the ability to receive, inventory, store, dispense tritium to experiments, and to dispose of tritiated waste while accurately monitoring the tritium inventory in the facility. This paper describes tritium accountancy in the STAR facility. A primary accountancy instrument is the tritium Storage and Assay System (SAS): a system designed to receive, assay, store, and dispense tritium to experiments. Presented are the methods used to calibrate and operate the SAS. Accountancy processes utilizing the Tritium Cleanup System (TCS), and the Stack Tritium Monitoring System (STMS) are also discussed. Also presented are the equations used to quantify the amount of tritium being received into the facility, transferred to experiments, and removed from the facility. Finally, the STAR tritium accountability database is discussed.

  5. STAR facility tritium accountancy

    SciTech Connect (OSTI)

    Pawelko, R. J.; Sharpe, J. P.; Denny, B. J.

    2008-07-15

    The Safety and Tritium Applied Research (STAR) facility has been established to provide a laboratory infrastructure for the fusion community to study tritium science associated with the development of safe fusion energy and other technologies. STAR is a radiological facility with an administrative total tritium inventory limit of 1.5 g (14,429 Ci) [1]. Research studies with moderate tritium quantities and various radionuclides are performed in STAR. Successful operation of the STAR facility requires the ability to receive, inventory, store, dispense tritium to experiments, and to dispose of tritiated waste while accurately monitoring the tritium inventory in the facility. This paper describes tritium accountancy in the STAR facility. A primary accountancy instrument is the tritium Storage and Assay System (SAS): a system designed to receive, assay, store, and dispense tritium to experiments. Presented are the methods used to calibrate and operate the SAS. Accountancy processes utilizing the Tritium Cleanup System (TCS), and the Stack Tritium Monitoring System (STMS) are also discussed. Also presented are the equations used to quantify the amount of tritium being received into the facility, transferred to experiments, and removed from the facility. Finally, the STAR tritium accountability database is discussed. (authors)

  6. CHARACTERIZATION OF THE MOST LUMINOUS STAR IN M33: A SUPER SYMBIOTIC BINARY

    SciTech Connect (OSTI)

    Miko?ajewska, Joanna; I?kiewicz, Krystian; Caldwell, Nelson; Shara, Michael M.

    2015-01-30

    We present the first spectrum of the most luminous infrared star in M33, and use it to demonstrate that the object is almost certainly a binary composed of a massive O star and a dust-enshrouded red hypergiant. This is the most luminous symbiotic binary ever discovered. Its radial velocity is an excellent match to that of the hydrogen gas in the disk of M33, supporting our interpretation that it is a very young and massive binary star.

  7. Blue Star Energy Services | Open Energy Information

    Open Energy Info (EERE)

    Blue Star Energy Services (Redirected from BlueStar) Jump to: navigation, search Name: Blue Star Energy Services Place: Illinois Phone Number: 866-258-3782 Website:...

  8. Wave Star Energy | Open Energy Information

    Open Energy Info (EERE)

    Star Energy Jump to: navigation, search Name: Wave Star Energy Place: Denmark Zip: DK-2920 Product: Denmark-based private wave device developer. References: Wave Star Energy1...

  9. Silver Star Wind Farm | Open Energy Information

    Open Energy Info (EERE)

    Star Wind Farm Jump to: navigation, search Name Silver Star Wind Farm Facility Silver Star Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner...

  10. Star Power | Princeton Plasma Physics Lab

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

    Star Power Star Power The U.S. Department of Energy's Princeton Plasma Physics Laboratory has released "Star Power," a new informational video that uses dramatic and beautiful...

  11. THE STRUCTURE OF THE STAR-FORMING CLUSTER RCW 38

    SciTech Connect (OSTI)

    Winston, E.; Wolk, S. J.; Bourke, T. L.; Spitzbart, B.; Megeath, S. T.; Gutermuth, R.

    2011-12-20

    We present a study of the structure of the high-mass star-forming region RCW 38 and the spatial distribution of its young stellar population. Spitzer Infrared Array Camera (IRAC) photometry (3-8 {mu}m) is combined with Two Micron All Sky Survey near-IR data to identify young stellar objects (YSOs) by IR-excess emission from their circumstellar material. Chandra X-ray data are used to identify class III pre-main-sequence stars lacking circumstellar material. We identify 624 YSOs: 23 class 0/I and 90 flat spectrum protostars, 437 class II stars, and 74 class III stars. We also identify 29 (27 new) O star candidates over the IRAC field. Seventy-two stars exhibit IR-variability, including 7 class 0/I and 12 flat spectrum YSOs. A further 177 tentative candidates are identified by their location in the IRAC [3.6] versus [3.6]-[5.8] color-magnitude diagram. We find strong evidence of subclustering in the region. Three subclusters were identified surrounding the central cluster, with massive and variable stars in each subcluster. The central region shows evidence of distinct spatial distributions of the protostars and pre-main-sequence stars. A previously detected IR cluster, DB2001{sub O}bj36, has been established as a subcluster of RCW 38. This suggests that star formation in RCW 38 occurs over a more extended area than previously thought. The gas-to-dust ratio is examined using the X-ray derived hydrogen column density, N{sub H} and the K-band extinction, and found to be consistent with the diffuse interstellar medium, in contrast with Serpens and NGC 1333. We posit that the high photoionizing flux of massive stars in RCW 38 affects the agglomeration of the dust grains.

  12. ENERGY STAR Webinar: How to Apply for the ENERGY STAR

    Broader source: Energy.gov [DOE]

    The U.S. Environmental Protection Agency (EPA) is hosting a webinar on how to apply for ENERGY STAR certification in Portfolio Manager. Understand the value of the ENERGY STAR certification, see...

  13. ENERGY STAR Webinar: ENERGY STAR and Green Building Rating Systems...

    Broader source: Energy.gov (indexed) [DOE]

    2:00PM to 3:00PM EDT ENERGY STAR Hosted by the U.S. Environmental Protection Agency's (EPA's) ENERGY STAR, this webinar will help attendees how to use EPA tools and resources to...

  14. General Relativity&Compact Stars

    SciTech Connect (OSTI)

    Glendenning, Norman K.

    2005-08-16

    Compact stars--broadly grouped as neutron stars and white dwarfs--are the ashes of luminous stars. One or the other is the fate that awaits the cores of most stars after a lifetime of tens to thousands of millions of years. Whichever of these objects is formed at the end of the life of a particular luminous star, the compact object will live in many respects unchanged from the state in which it was formed. Neutron stars themselves can take several forms--hyperon, hybrid, or strange quark star. Likewise white dwarfs take different forms though only in the dominant nuclear species. A black hole is probably the fate of the most massive stars, an inaccessible region of spacetime into which the entire star, ashes and all, falls at the end of the luminous phase. Neutron stars are the smallest, densest stars known. Like all stars, neutron stars rotate--some as many as a few hundred times a second. A star rotating at such a rate will experience an enormous centrifugal force that must be balanced by gravity or else it will be ripped apart. The balance of the two forces informs us of the lower limit on the stellar density. Neutron stars are 10{sup 14} times denser than Earth. Some neutron stars are in binary orbit with a companion. Application of orbital mechanics allows an assessment of masses in some cases. The mass of a neutron star is typically 1.5 solar masses. They can therefore infer their radii: about ten kilometers. Into such a small object, the entire mass of our sun and more, is compressed.

  15. Purchasing Energy-Efficient Commercial Gas Water Heaters | Department of

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Energy Gas Water Heaters Purchasing Energy-Efficient Commercial Gas Water Heaters The Federal Energy Management Program (FEMP) provides acquisition guidance for commercial gas water heaters (CWHs), a product category covered by ENERGY STAR efficiency requirements. Federal laws and requirements mandate that agencies purchase ENERGY STAR-qualified products or FEMP-designated products in all product categories covered by these programs and in any acquisition actions that are not specifically

  16. Purchasing Energy-Efficient Residential Gas Storage Water Heaters |

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Department of Energy Gas Storage Water Heaters Purchasing Energy-Efficient Residential Gas Storage Water Heaters The Federal Energy Management Program (FEMP) provides acquisition guidance for residential gas storage water heaters, a product category covered by ENERGY STAR efficiency requirements. Federal laws and requirements mandate that agencies purchase ENERGY STAR-qualified products or FEMP-designated products in all product categories covered by these programs and in any acquisition

  17. Synthetic guide star generation

    DOE Patents [OSTI]

    Payne, Stephen A.; Page, Ralph H.; Ebbers, Christopher A.; Beach, Raymond J.

    2004-03-09

    A system for assisting in observing a celestial object and providing synthetic guide star generation. A lasing system provides radiation at a frequency at or near 938 nm and radiation at a frequency at or near 1583 nm. The lasing system includes a fiber laser operating between 880 nm and 960 nm and a fiber laser operating between 1524 nm and 1650 nm. A frequency-conversion system mixes the radiation and generates light at a frequency at or near 589 nm. A system directs the light at a frequency at or near 589 nm toward the celestial object and provides synthetic guide star generation.

  18. A Star on Earth

    ScienceCinema (OSTI)

    Prager, Stewart; Zwicker, Andrew; Hammet, Greg; Tresemer, Kelsey; Diallo, Ahmed

    2014-06-06

    At the Energy Department's Princeton Plasma Physics Lab, scientists are trying to accomplish what was once considered the realm of science fiction: create a star on Earth. The National Spherical Torus Experiment (NSTX) is a magnetic fusion device that is used to study the physics principles of spherically shaped plasmas -- hot ionized gases in which, under the right conditions, nuclear fusion will occur. Fusion is the energy source of the sun and all of the stars. Not just limited to theoretical work, the NSTX is enabling cutting-edge research to develop fusion as a future energy source.

  19. Synthetic guide star generation

    SciTech Connect (OSTI)

    Payne, Stephen A; Page, Ralph H; Ebbers, Christopher A; Beach, Raymond J

    2008-06-10

    A system for assisting in observing a celestial object and providing synthetic guide star generation. A lasing system provides radiation at a frequency at or near 938 nm and radiation at a frequency at or near 1583 nm. The lasing system includes a fiber laser operating between 880 nm and 960 nm and a fiber laser operating between 1524 nm and 1650 nm. A frequency-conversion system mixes the radiation and generates light at a frequency at or near 589 nm. A system directs the light at a frequency at or near 589 nm toward the celestial object and provides synthetic guide star generation.

  20. A Star on Earth

    SciTech Connect (OSTI)

    Prager, Stewart; Zwicker, Andrew; Hammet, Greg; Tresemer, Kelsey; Diallo, Ahmed

    2014-03-05

    At the Energy Department's Princeton Plasma Physics Lab, scientists are trying to accomplish what was once considered the realm of science fiction: create a star on Earth. The National Spherical Torus Experiment (NSTX) is a magnetic fusion device that is used to study the physics principles of spherically shaped plasmas -- hot ionized gases in which, under the right conditions, nuclear fusion will occur. Fusion is the energy source of the sun and all of the stars. Not just limited to theoretical work, the NSTX is enabling cutting-edge research to develop fusion as a future energy source.

  1. ENERGY STAR Webinar: How to Apply for ENERGY STAR

    Broader source: Energy.gov [DOE]

    The U.S. Environmental Protection Agency (EPA) ENERGY STAR is hosting a webinar on how to apply for ENERGY STAR Certification in Portfolio Manager. Understand the value of the ENERGY STAR certification, see the step-by-step process of applying, and gain tips to help your property get from application to award.

  2. CFL Manufacturers: ENERGY STAR Letters

    Broader source: Energy.gov [DOE]

    DOE issued letters to 25 manufacturers of compact fluorescent lamps (CFLs) involving various models after PEARL Cycle 9 testing indicated that the models do not meet the ENERGY STAR specification and, therefore, are disqualified from the ENERGY STAR Program.

  3. Energy Star | Open Energy Information

    Open Energy Info (EERE)

    Energy Star Jump to: navigation, search Energystarlogo.jpg Contents 1 What's new 2 About ENERGY STAR 3 For the Home 4 For Business 5 History 6 References What's new On March 15,...

  4. Comet Riders--Nuclear nomads to the stars

    SciTech Connect (OSTI)

    Angelo, J.A. Jr. ); Buden, D. )

    1991-01-01

    This paper describes the potential role of an evolutionary family of advanced space nuclear power systems (solid core reactor, gas core reactor, and thermonulcear fusion systems) in the detailed exploration of Solar System comets and in the use of interstellar comes to support migratory journeys to the stars by both human beings and their smart robot systems. 14 refs., 5 figs., 2 tabs.

  5. ORIGIN OF THE GALAXY MASS-METALLICITY-STAR FORMATION RELATION

    SciTech Connect (OSTI)

    Harwit, Martin; Brisbin, Drew

    2015-02-20

    We describe an equilibrium model that links the metallicity of low-redshift galaxies to stellar evolution models. It enables the testing of different stellar initial mass functions and metal yields against observed galaxy metallicities. We show that the metallicities of more than 80,000 Sloan Digital Sky Survey galaxies in the low-redshift range 0.07 ? z ? 0.3 considerably constrain stellar evolution models that simultaneously relate galaxy stellar mass, metallicity, and star formation rates to the infall rate of low-metallicity extragalactic gas and outflow of enriched matter. A feature of our model is that it encompasses both the active star forming phases of a galaxy and epochs during which the same galaxy may lie fallow. We show that the galaxy mass-metallicity-star formation relation can be traced to infall of extragalactic gas mixing with native gas from host galaxies to form stars of observed metallicities, the most massive of which eject oxygen into extragalactic space. Most consequential among our findings is that, on average, extragalactic infall accounts for one half of the gas required for star formation, a ratio that is remarkably constant across galaxies with stellar masses ranging at least from M* = 2 10{sup 9} to 6 10{sup 10} M {sub ?}. This leads us to propose that star formation is initiated when extragalactic infall roughly doubles the mass of marginally stable interstellar clouds. The processes described may also account quantitatively for the metallicity of extragalactic space, though to check this the fraction of extragalactic baryons will need to be more firmly established.

  6. The interstellar medium and star formation in local galaxies: Variations of the star formation law in simulations

    SciTech Connect (OSTI)

    Becerra, Fernando; Escala, Andrés

    2014-05-01

    We use the adaptive mesh refinement code Enzo to model the interstellar medium (ISM) in isolated local disk galaxies. The simulation includes a treatment for star formation and stellar feedback. We get a highly supersonic turbulent disk, which is fragmented at multiple scales and characterized by a multi-phase ISM. We show that a Kennicutt-Schmidt relation only holds when averaging over large scales. However, values of star formation rates and gas surface densities lie close in the plot for any averaging size. This suggests an intrinsic relation between stars and gas at cell-size scales, which dominates over the global dynamical evolution. To investigate this effect, we develop a method to simulate the creation of stars based on the density field from the snapshots, without running the code again. We also investigate how the star formation law is affected by the characteristic star formation timescale, the density threshold, and the efficiency considered in the recipe. We find that the slope of the law varies from ∼1.4 for a free-fall timescale, to ∼1.0 for a constant depletion timescale. We further demonstrate that a power law is recovered just by assuming that the mass of the new stars is a fraction of the mass of the cell m {sub *} = ερ{sub gas}Δx {sup 3}, with no other physical criteria required. We show that both efficiency and density threshold do not affect the slope, but the right combination of them can adjust the normalization of the relation, which in turn could explain a possible bi-modality in the law.

  7. Resolved star formation on sub-galactic scales in a merger at z = 1.7

    SciTech Connect (OSTI)

    Whitaker, Katherine E.; Rigby, Jane R.; Teng, Stacy H.; Brammer, Gabriel B.; Gladders, Michael D.; Sharon, Keren; Wuyts, Eva

    2014-08-01

    We present a detailed analysis of Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) G141 grism spectroscopy for seven star-forming regions of the highly magnified lensed starburst galaxy RCSGA 032727-132609 at z = 1.704. We measure the spatial variations of the extinction in RCS0327 through the observed H?/H? emission line ratios, finding a constant average extinction of E(B V){sub gas} = 0.40 0.07. We infer that the star formation is enhanced as a result of an ongoing interaction, with measured star formation rates derived from demagnified, extinction-corrected H? line fluxes for the individual star-forming clumps falling >1-2 dex above the star formation sequence. When combining the HST/WFC3 [O III] ?5007/H? emission line ratio measurements with [N II]/H? line ratios from Wuyts et al., we find that the majority of the individual star-forming regions fall along the local 'normal' abundance sequence. With the first detections of the He I ?5876 and He II ?4686 recombination lines in a distant galaxy, we probe the massive-star content of the star-forming regions in RCS0327. The majority of the star-forming regions have a He I ?5876 to H? ratio consistent with the saturated maximum value, which is only possible if they still contain hot O-stars. Two regions have lower ratios, implying that their last burst of new star formation ended ?5 Myr ago. Together, the He I ?5876 and He II ?4686 to H? line ratios provide indirect evidence for the order in which star formation is stopping in individual star-forming knots of this high-redshift merger. We place the spatial variations of the extinction, star formation rate and ionization conditions in the context of the star formation history of RCS0327.

  8. Stellar signatures of AGN-jet-triggered star formation

    SciTech Connect (OSTI)

    Dugan, Zachary; Silk, Joseph; Bryan, Sarah; Gaibler, Volker; Haas, Marcel

    2014-12-01

    To investigate feedback between relativistic jets emanating from active galactic nuclei and the stellar population of the host galaxy, we analyze the long-term evolution of the orbits of the stars formed in the galaxy-scale simulations by Gaibler et al. of jets in massive, gas-rich galaxies at z ? 2-3. We find strong, jet-induced differences in the resulting stellar populations of galaxies that host relativistic jets and galaxies that do not, including correlations in stellar locations, velocities, and ages. Jets are found to generate distributions of increased radial and vertical velocities that persist long enough to effectively augment the stellar structure of the host. The jets cause the formation of bow shocks that move out through the disk, generating rings of star formation within the disk. The bow shock often accelerates pockets of gas in which stars form, yielding populations of stars with significant radial and vertical velocities, some of which have large enough velocities to escape the galaxy. These stellar population signatures can serve to identify past jet activity as well as jet-induced star formation.

  9. Neutron Star Science with the NuSTAR

    SciTech Connect (OSTI)

    Vogel, J. K.

    2015-10-16

    The Nuclear Spectroscopic Telescope Array (NuSTAR), launched in June 2012, helped scientists obtain for the first time a sensitive high-­energy X-­ray map of the sky with extraordinary resolution. This pioneering telescope has aided in the understanding of how stars explode and neutron stars are born. LLNL is a founding member of the NuSTAR project, with key personnel on its optics and science team. We used NuSTAR to observe and analyze the observations of different neutron star classes identified in the last decade that are still poorly understood. These studies not only help to comprehend newly discovered astrophysical phenomena and emission processes for members of the neutron star family, but also expand the utility of such observations for addressing broader questions in astrophysics and other physics disciplines. For example, neutron stars provide an excellent laboratory to study exotic and extreme phenomena, such as the equation of state of the densest matter known, the behavior of matter in extreme magnetic fields, and the effects of general relativity. At the same time, knowing their accurate populations has profound implications for understanding the life cycle of massive stars, star collapse, and overall galactic evolution.

  10. Local STAR Libraries

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

    Local STAR Libraries Local STAR Libraries The libraries listed below are built locally at PDSF and are available under the chos environment sl53. The 32sl44 chos environment has been retire but the libraries are still listed for reference. Version Tag ROOT Version Status Mode Date Comment SL12b (new) SL12b 5.22.00 built debug 4/17/12 SL5.3 SL12a SL12a 5.22.00 built debug 3/14/12 SL5.3 SL11e SL11e 5.22.00 built debug 11/30/11 SL5.3 SL11d (pro) SL11d 5.22.00 built debug 8/1/11 SL5.3 SL11c SL11c_1

  11. Relativistic structure, stability, and gravitational collapse of charged neutron stars

    SciTech Connect (OSTI)

    Ghezzi, Cristian R.

    2005-11-15

    Charged stars have the potential of becoming charged black holes or even naked singularities. We present a set of numerical solutions of the Tolman-Oppenheimer-Volkov equations that represents spherical charged compact stars in hydrostatic equilibrium. The stellar models obtained are evolved forward in time integrating the Einstein-Maxwell field equations. We assume an equation of state of a neutron gas at zero temperature. The charge distribution is taken as being proportional to the rest mass density distribution. The set of solutions present an unstable branch, even with charge-to-mass ratios arbitrarily close to the extremum case. We perform a direct check of the stability of the solutions under strong perturbations and for different values of the charge-to-mass ratio. The stars that are in the stable branch oscillate and do not collapse, while models in the unstable branch collapse directly to form black holes. Stars with a charge greater than or equal to the extreme value explode. When a charged star is suddenly discharged, it does not necessarily collapse to form a black hole. A nonlinear effect that gives rise to the formation of a shell of matter (in supermassive stars), is negligible in the present simulations. The results are in agreement with the third law of black hole thermodynamics and with the cosmic censorship conjecture.

  12. PROTOSTELLAR OUTFLOWS AND RADIATIVE FEEDBACK FROM MASSIVE STARS

    SciTech Connect (OSTI)

    Kuiper, Rolf; Yorke, Harold W.; Turner, Neal J. E-mail: Harold.W.Yorke@jpl.nasa.gov

    2015-02-20

    We carry out radiation hydrodynamical simulations of the formation of massive stars in the super-Eddington regime including both their radiative feedback and protostellar outflows. The calculations start from a prestellar core of dusty gas and continue until the star stops growing. The accretion ends when the remnants of the core are ejected, mostly by the force of the direct stellar radiation in the polar direction and elsewhere by the reradiated thermal infrared radiation. How long the accretion persists depends on whether the protostellar outflows are present. We set the mass outflow rate to 1% of the stellar sink particle's accretion rate. The outflows open a bipolar cavity extending to the core's outer edge, through which the thermal radiation readily escapes. The radiative flux is funneled into the polar directions while the core's collapse proceeds near the equator. The outflow thus extends the ''flashlight effect'', or anisotropic radiation field, found in previous studies from the few hundred AU scale of the circumstellar disk up to the 0.1 parsec scale of the core. The core's flashlight effect allows core gas to accrete on the disk for longer, in the same way that the disk's flashlight effect allows disk gas to accrete on the star for longer. Thus although the protostellar outflows remove material near the core's poles, causing slower stellar growth over the first few free-fall times, they also enable accretion to go on longer in our calculations. The outflows ultimately lead to stars of somewhat higher mass.

  13. ENERGY STAR Webinar: How to Apply for the ENERGY STAR

    Broader source: Energy.gov [DOE]

    The U.S. Environmental Protection Agency (EPA) is hosting a webinar on how to apply for ENERGY STAR certification in Portfolio Manager.

  14. EXTENDED SCHMIDT LAW: ROLE OF EXISTING STARS IN CURRENT STAR...

    Office of Scientific and Technical Information (OSTI)

    Country of Publication: United States Language: English Subject: 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; DENSITY; GALACTIC EVOLUTION; MASS; STARS; SURFACES EVOLUTION; PHYSICAL ...

  15. STAR CLUSTERS IN A NUCLEAR STAR FORMING RING: THE DISAPPEARING STRING OF PEARLS

    SciTech Connect (OSTI)

    Visnen, Petri; Barway, Sudhanshu; Randriamanakoto, Zara

    2014-12-20

    An analysis of the star cluster population in a low-luminosity early-type galaxy, NGC2328, is presented. The clusters are found in a tight star forming nuclear spiral/ring pattern and we also identify a bar from structural two-dimensional decomposition. These massive clusters are forming very efficiently in the circumnuclear environment and they are young, possibly all less than 30 Myr of age. The clusters indicate an azimuthal age gradient, consistent with a ''pearls-on-a-string'' formation scenario, suggesting bar-driven gas inflow. The cluster mass function has a robust down turn at low masses at all age bins. Assuming clusters are born with a power-law distribution, this indicates extremely rapid disruption at timescales of just several million years. If found to be typical, it means that clusters born in dense circumnuclear rings do not survive to become old globular clusters in non-interacting systems.

  16. WIPP Hazardous Waste Permit - Class 1* (star) Modifications

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

    * (star) Modifications Submitted for NMED Approval

  17. A PARAMETRIC STUDY OF POSSIBLE SOLUTIONS TO THE HIGH-REDSHIFT OVERPRODUCTION OF STARS IN MODELED DWARF GALAXIES

    SciTech Connect (OSTI)

    White, Catherine E.; Somerville, Rachel S.; Ferguson, Henry C.

    2015-02-01

    Both numerical hydrodynamic and semi-analytic cosmological models of galaxy formation struggle to match observed star formation histories of galaxies in low-mass halos (M {sub H} ? 10{sup 11} M {sub ?}), predicting more star formation at high redshift and less star formation at low redshift than observed. The fundamental problem is that galaxies' gas accretion and star formation rates are too closely coupled in the models: the accretion rate largely drives the star formation rate. Observations point to gas accretion rates that outpace star formation at high redshift, resulting in a buildup of gas and a delay in star formation until lower redshifts. We present three empirical adjustments of standard recipes in a semi-analytic model motivated by three physical scenarios that could cause this decoupling: (1) the mass-loading factors of outflows driven by stellar feedback may have a steeper dependence on halo mass at earlier times, (2) the efficiency of star formation may be lower in low-mass halos at high redshift, and (3) gas may not be able to accrete efficiently onto the disk in low-mass halos at high redshift. These new recipes, once tuned, better reproduce the evolution of f {sub *}? M {sub *}/M {sub H} as a function of halo mass as derived from abundance matching over redshifts z = 0 to 3, though they have different effects on cold gas fractions, star formation rates, and metallicities. Changes to gas accretion and stellar-driven winds are promising, while direct modification of the star formation timescale requires drastic measures that are not physically well motivated.

  18. Purchasing Energy-Efficient Commercial Gas Water Heaters

    Office of Energy Efficiency and Renewable Energy (EERE)

    The Federal Energy Management Program (FEMP) provides acquisition guidance for commercial gas water heaters (CWHs), a product category covered by ENERGY STAR efficiency requirements. Federal laws and requirements mandate that agencies purchase ENERGY STAR-qualified products or FEMP-designated products in all product categories covered by these programs and in any acquisition actions that are not specifically exempted by law.

  19. Delayed star formation in isolated dwarf galaxies: Hubble space telescope star formation history of the Aquarius dwarf irregular

    SciTech Connect (OSTI)

    Cole, Andrew A.; Weisz, Daniel R.; Dolphin, Andrew E.; Skillman, Evan D.; McConnachie, Alan W.; Brooks, Alyson M.; Leaman, Ryan E-mail: drw@ucsc.edu E-mail: skillman@astro.umn.edu E-mail: abrooks@physics.rutgers.edu

    2014-11-01

    We have obtained deep images of the highly isolated (d = 1 Mpc) Aquarius dwarf irregular galaxy (DDO 210) with the Hubble Space Telescope Advanced Camera for Surveys. The resulting color-magnitude diagram (CMD) reaches more than a magnitude below the oldest main-sequence turnoff, allowing us to derive the star formation history (SFH) over the entire lifetime of the galaxy with a timing precision of ?10% of the lookback time. Using a maximum likelihood fit to the CMD we find that only ?10% of all star formation in Aquarius took place more than 10 Gyr ago (lookback time equivalent to redshift z ? 2). The star formation rate increased dramatically ?6-8 Gyr ago (z ? 0.7-1.1) and then declined until the present time. The only known galaxy with a more extreme confirmed delay in star formation is Leo A, a galaxy of similar M {sub H} {sub I}/M {sub *}, dynamical mass, mean metallicity, and degree of isolation. The delayed stellar mass growth in these galaxies does not track the mean dark matter accretion rate from CDM simulations. The similarities between Leo A and Aquarius suggest that if gas is not removed from dwarf galaxies by interactions or feedback, it can linger for several gigayears without cooling in sufficient quantity to form stars efficiently. We discuss possible causes for the delay in star formation including suppression by reionization and late-time mergers. We find reasonable agreement between our measured SFHs and select cosmological simulations of isolated dwarfs. Because star formation and merger processes are both stochastic in nature, delayed star formation in various degrees is predicted to be a characteristic (but not a universal) feature of isolated small galaxies.

  20. Carbon-enhanced metal-poor stars: relics from the dark ages

    SciTech Connect (OSTI)

    Cooke, Ryan J.; Madau, Piero

    2014-08-20

    We use detailed nucleosynthesis calculations and a realistic prescription for the environment of the first stars to explore the first episodes of chemical enrichment that occurred during the dark ages. Based on these calculations, we propose a novel explanation for the increased prevalence of carbon-enhanced metal-poor (CEMP) stars with decreasing Fe abundance: the observed chemistry for the most metal-poor Galactic halo stars is the result of an intimate link between the explosions of the first stars and their host minihalo's ability to retain its gas. Specifically, high-energy supernovae produce a near solar ratio of C/Fe, but are effective in evacuating the gas from their host minihalo, thereby suppressing the formation of a second generation of stars. On the other hand, minihalos that host low-energy supernovae are able to retain their gas and form a second stellar generation, but, as a result, the second stars are born with a supersolar ratio of C/Fe. Our models are able to accurately reproduce the observed distributions of [C/Fe] and [Fe/H], as well as the fraction of CEMP stars relative to non-CEMP stars as a function of [Fe/H] without any free parameters. We propose that the present lack of chemical evidence for very massive stars (≳ 140 M {sub ☉}) that ended their lives as a highly energetic pair-instability supernova does not imply that such stars were rare or did not exist; the chemical products of these very massive first stars may have been evacuated from their host minihalos and were never incorporated into subsequent generations of stars. Finally, our models suggest that the most Fe-poor stars currently known may have seen the enrichment from a small multiple of metal-free stars, and need not have been exclusively enriched by a solitary first star. These calculations also add further support to the possibility that some of the surviving dwarf satellite galaxies of the Milky Way are the relics of the first galaxies.

  1. DETAILED ABUNDANCES OF TWO VERY METAL-POOR STARS IN DWARF GALAXIES

    SciTech Connect (OSTI)

    Kirby, Evan N.; Cohen, Judith G.

    2012-12-01

    The most metal-poor stars in dwarf spheroidal galaxies (dSphs) can show the nucleosynthetic patterns of one or a few supernovae (SNe). These SNe could have zero metallicity, making metal-poor dSph stars the closest surviving links to Population III stars. Metal-poor dSph stars also help to reveal the formation mechanism of the Milky Way (MW) halo. We present the detailed abundances from Keck/HIRES spectroscopy for two very metal-poor stars in two MW dSphs. One star, in the Sculptor dSph, has [Fe I/H] = -2.40. The other star, in the Ursa Minor dSph, has [Fe I/H] = -3.16. Both stars fall in the previously discovered low-metallicity, high-[{alpha}/Fe] plateau. Most abundance ratios of very metal-poor stars in these two dSphs are largely consistent with very metal-poor halo stars. However, the abundances of Na and some r-process elements lie at the lower end of the envelope defined by inner halo stars of similar metallicity. We propose that the metallicity dependence of SN yields is the cause. The earliest SNe in low-mass dSphs have less gas to pollute than the earliest SNe in massive halo progenitors. As a result, dSph stars at -3 < [Fe/H] < -2 sample SNe with [Fe/H] << -3, whereas halo stars in the same metallicity range sample SNe with [Fe/H] {approx} -3. Consequently, enhancements in [Na/Fe] and [r/Fe] were deferred to higher metallicity in dSphs than in the progenitors of the inner halo.

  2. Streamlining ENERGY STAR Appliance Testing

    Broader source: Energy.gov [DOE]

    To save taxpayer dollars and help lower the costs of innovative energy-efficient technologies, the Energy Department is streamlining ENERGY STAR testing for appliances.

  3. STAR Teaching Program Application Period

    Broader source: Energy.gov [DOE]

    The Science Teacher and Researcher (STAR) Researcher program, a collaborative project of California State University, provides pre-service and early career science teachers with eight week long...

  4. ENERGY STAR Webinar: How to Apply for the ENERGY STAR

    Broader source: Energy.gov [DOE]

    The U.S. Environmental Protection Agency (EPA) is hosting a webinar on how to apply for ENERGY STAR certification in Portfolio Manager. Understand the value of the ENERGY STAR certification, see the step-by-step process of applying, and gain tips to help your property get from application to award.

  5. StarTex Power | Open Energy Information

    Open Energy Info (EERE)

    StarTex Power Place: Texas Website: www.startexpower.com Twitter: @StarTexPower Facebook: https:www.facebook.comStarTexPower Outage Hotline: 1-866-917-8271 References: EIA...

  6. BUILDING LATE-TYPE SPIRAL GALAXIES BY IN-SITU AND EX-SITU STAR FORMATION

    SciTech Connect (OSTI)

    Pillepich, Annalisa; Madau, Piero; Mayer, Lucio

    2015-02-01

    We analyze the formation and evolution of the stellar components in ''Eris'', a 120pc resolution cosmological hydrodynamic simulation of a late-type spiral galaxy. The simulation includes the effects of a uniform UV background, a delayed-radiative-cooling scheme for supernova feedback, and a star formation recipe based on a high gas density threshold. It allows a detailed study of the relative contributions of ''in-situ'' (within the main host) and ''ex-situ'' (within satellite galaxies) star formation to each major Galactic component in a close Milky Way analog. We investigate these two star-formation channels as a function of galactocentric distance, along different lines of sight above and along the disk plane, and as a function of cosmic time. We find that: (1) approximately 70% of today's stars formed in-situ; (2) more than two thirds of the ex-situ stars formed within satellites after infall; (3) the majority of ex-situ stars are found today in the disk and in the bulge; (4) the stellar halo is dominated by ex-situ stars, whereas in-situ stars dominate the mass profile at distances ? 5 kpc from the center at high latitudes; and (5) approximately 25% of the inner, r ? 20 kpc, halo is composed of in-situ stars that have been displaced from their original birth sites during Eris' early assembly history.

  7. StarSolar Corporation | Open Energy Information

    Open Energy Info (EERE)

    StarSolar Corporation Jump to: navigation, search Name: StarSolar Corporation Place: Cambridge, Massachusetts Product: Developing a nanostructured 'photonic crystal' PV cell with...

  8. Verifying the ENERGY STAR Certification Application

    Broader source: Energy.gov [DOE]

    Do you verify commercial building applications for ENERGY STAR certification? This webinar, based on the ENERGY STAR Guide for Licensed Professionals, covers the role of the licensed professional,...

  9. MagStar Technologies | Open Energy Information

    Open Energy Info (EERE)

    MagStar Technologies Jump to: navigation, search Name: MagStar Technologies Place: Hopkins, MN Information About Partnership with NREL Partnership with NREL Yes Partnership Type...

  10. Five Star Technologies | Open Energy Information

    Open Energy Info (EERE)

    Star Technologies Jump to: navigation, search Name: Five Star Technologies Place: Independence, Ohio Zip: 44131 Sector: Solar Product: US manufacturer of inks and pastes for the...

  11. Star Point Wind Farm | Open Energy Information

    Open Energy Info (EERE)

    Point Wind Farm Jump to: navigation, search Name Star Point Wind Farm Facility Star Point Wind Farm Sector Wind energy Facility Type Commercial Scale Wind Facility Status In...

  12. ENERGY STAR Webinar: Portfolio Manager 101

    Broader source: Energy.gov [DOE]

    Hosted by the U.S. Environmental Protection Agency's (EPA's) ENERGY STAR, this webinar will introduce and demonstrate the EPA's ENERGY STAR Portfolio Manager tool.

  13. Home Performance with ENERGY STAR Program Winners Are Committed to Energy Savings

    Broader source: Energy.gov [DOE]

    The Energy Department (DOE) and the Environmental Protection Agency (EPA) honored 128 organizations in 33 states at the 2015 ENERGY STAR Partner of the Year Awards for their commitment to saving energy and protecting the environment through superior energy efficiency achievements.The winners were chosen from a vast network of 16,000 ENERGY STAR partners.The awards honor businesses and organizations for their outstanding contributions to reducing greenhouse gas emissions through energy efficiency.

  14. On the onset of secondary stellar generations in giant star-forming regions and massive star clusters

    SciTech Connect (OSTI)

    Palou, J.; Wnsch, R.; Tenorio-Tagle, G.

    2014-09-10

    Here we consider the strong evolution experienced by the matter reinserted by massive stars, both in giant star-forming regions driven by a constant star formation rate and in massive and coeval superstar clusters. In both cases we take into consideration the changes induced by stellar evolution on the number of massive stars, the number of ionizing photons, and the integrated mechanical luminosity of the star-forming regions. The latter is at all times compared with the critical luminosity that defines, for a given size, the lower mechanical luminosity limit above which the matter reinserted via strong winds and supernova explosions suffers frequent and recurrent thermal instabilities that reduce its temperature and pressure and inhibit its exit as part of a global wind. Instead, the unstable reinserted matter is compressed by the pervasive hot gas, and photoionization maintains its temperature at T ? 10{sup 4} K. As the evolution proceeds, more unstable matter accumulates and the unstable clumps grow in size. Here we evaluate the possible self-shielding of thermally unstable clumps against the UV radiation field. Self-shielding allows for a further compression of the reinserted matter, which rapidly develops a high-density neutral core able to absorb in its outer skin the incoming UV radiation. Under such conditions the cold (T ? 10 K) neutral cores soon surpass the Jeans limit and become gravitationally unstable, creating a new stellar generation with the matter reinserted by former massive stars. We present the results of several calculations of this positive star formation feedback scenario promoted by strong radiative cooling and mass loading.

  15. EPA ENERGY STAR Webcast: Value of ENERGY STAR Certification

    Broader source: Energy.gov [DOE]

    For thousands of organizations, ENERGY STAR is the simple choice for saving money and demonstrating environmental leadership to the public. Lower energy costs aren't the only financial benefit of...

  16. EPA ENERGY STAR Webinar: ENERGY STAR Portfolio Manager 201

    Broader source: Energy.gov [DOE]

    Continue to learn about EPA’s ENERGY STAR Portfolio Manager tool, with a deeper dive into more advanced functionalities such as: managing and tracking changes to your property uses over time; using...

  17. Purchasing Energy-Efficient Residential Whole-Home Gas Tankless Water

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Heaters | Department of Energy Whole-Home Gas Tankless Water Heaters Purchasing Energy-Efficient Residential Whole-Home Gas Tankless Water Heaters The Federal Energy Management Program (FEMP) provides acquisition guidance for residential whole-home gas tankless water heaters, a product category covered by ENERGY STAR efficiency requirements. Federal laws and requirements mandate that agencies purchase ENERGY STAR-qualified products or FEMP-designated products in all product categories

  18. A Heavy Flavor Tracker for STAR

    SciTech Connect (OSTI)

    Xu, Z.; Chen, Y.; Kleinfelder, S.; Koohi, A.; Li, S.; Huang, H.; Tai, A.; Kushpil, V.; Sumbera, M.; Colledani, C.; Dulinski, W.; Himmi,A.; Hu, C.; Shabetai, A.; Szelezniak, M.; Valin, I.; Winter, M.; Surrow,B.; Van Nieuwenhuizen, G.; Bieser, F.; Gareus, R.; Greiner, L.; Lesser,F.; Matis, H.S.; Oldenburg, M.; Ritter, H.G.; Pierpoint, L.; Retiere, F.; Rose, A.; Schweda, K.; Sichtermann, E.; Thomas, J.H.; Wieman, H.; Yamamoto, E.; Kotov, I.

    2005-03-14

    We propose to construct a Heavy Flavor Tracker (HFT) for the STAR experiment at RHIC. The HFT will bring new physics capabilities to STAR and it will significantly enhance the physics capabilities of the STAR detector at central rapidities. The HFT will ensure that STAR will be able to take heavy flavor data at all luminosities attainable throughout the proposed RHIC II era.

  19. Gas venting

    DOE Patents [OSTI]

    Johnson, Edwin F.

    1976-01-01

    Improved gas venting from radioactive-material containers which utilizes the passageways between interbonded impervious laminae.

  20. ENERGY STAR Portfolio Manager 201

    Broader source: Energy.gov [DOE]

    Continue to learn about EPA’s new ENERGY STAR Portfolio Manager tool, with a deeper dive into more advanced functionalities such as: managing and tracking changes to your property uses over time;...

  1. ENERGY STAR Portfolio Manager 101

    Broader source: Energy.gov [DOE]

    Join us as we introduce and demonstrate the core functionality of EPA’s ENERGY STAR Portfolio Manager tool. Attendees will learn how to: navigate Portfolio Manager; add a property and enter details...

  2. The origin of the most iron-poor star

    SciTech Connect (OSTI)

    Marassi, S.; Schneider, R.; Limongi, M. [INAF/Osservatorio Astronomico di Roma, Via di Frascati 33, I-00040 Monteporzio (Italy); Chiaki, G.; Yoshida, N. [Department of Physics, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033 (Japan); Omukai, K. [Astronomical Institute, Tohoku University, Sendai 980-8578 (Japan); Nozawa, T. [National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Chieffi, A., E-mail: stefania.marassi@oa-roma.inaf.it [INAF/IASF, Via Fosso del Cavaliere 100, I-00133 Roma (Italy)

    2014-10-20

    We investigate the origin of carbon-enhanced metal-poor (CEMP) stars starting from the recently discovered [Fe/H] < -7.1 star SMSS J031300. We show that the elemental abundances observed on the surface of SMSS J031300 can be well fit by the yields of faint, metal-free, supernovae (SNe). Using properly calibrated faint SN explosion models, we study, for the first time, the formation of dust grains in such carbon-rich, iron-poor SN ejecta. Calculations are performed assuming both unmixed and uniformly mixed ejecta and taking into account the partial destruction by the SN reverse shock. We find that, due to the paucity of refractory elements beside carbon, amorphous carbon is the only grain species to form, with carbon condensation efficiencies that range between (0.15 and 0.84), resulting in dust yields in the range (0.025-2.25) M {sub ?}. We follow the collapse and fragmentation of a star-forming cloud enriched by the products of these faint SN explosions and we explore the role played by fine structure line cooling and dust cooling. We show that even if grain growth during the collapse has a minor effect of the dust-to-gas ratio, due to C depletion into CO molecules at an early stage of the collapse, the formation of CEMP low-mass stars, such as SMSS J031300, could be triggered by dust cooling and fragmentation. A comparison between model predictions and observations of a sample of C-normal and C-rich metal-poor stars supports the idea that a single common pathway may be responsible for the formation of the first low-mass stars.

  3. Covered Product Category: Residential Gas Furnaces

    Broader source: Energy.gov [DOE]

    FEMP provides acquisition guidance across a variety of product categories, including residential gas furnaces, which are an ENERGY STAR-qualified product category. Federal laws and requirements mandate that agencies meet these efficiency requirements in all procurement and acquisition actions that are not specifically exempted by law.

  4. Green Star Products Inc GSPI | Open Energy Information

    Open Energy Info (EERE)

    Star Products Inc GSPI Jump to: navigation, search Name: Green Star Products Inc (GSPI) Place: Chula Vista, California Zip: 91911 Product: Green Star is building two 200-hectare...

  5. Natural Gas Weekly Update

    Gasoline and Diesel Fuel Update (EIA)

    Indicate Increases in ENERGY STAR qualified Homes in the United States. The number of ENERGY STAR qualified homes built in the United States has increased nearly 20-fold...

  6. A CORRELATION BETWEEN SURFACE DENSITIES OF YOUNG STELLAR OBJECTS AND GAS IN EIGHT NEARBY MOLECULAR CLOUDS

    SciTech Connect (OSTI)

    Gutermuth, R. A.; Pipher, J. L.; Megeath, S. T.; Allen, T. S.; Myers, P. C.; Allen, L. E.

    2011-10-01

    We report the discovery and characterization of a power-law correlation between the local surface densities of Spitzer-identified, dusty young stellar objects (YSOs) and the column density of gas (as traced by near-IR extinction) in eight molecular clouds within 1 kpc and with 100 or more known YSOs. This correlation, which appears in data smoothed over size scales of {approx}1 pc, varies in quality from cloud to cloud; those clouds with tight correlations, MonR2 and Ophiuchus, are fit with power laws of slope 2.67 and 1.87, respectively. The spread in the correlation is attributed primarily to local gas disruption by stars that formed there or to the presence of very young subregions at the onset of star formation. We explore the ratio of the number of Class II to Class I sources, a proxy for the star formation age of a region, as a function of gas column density; this analysis reveals a declining Class II to Class I ratio with increasing column density. We show that the observed star-gas correlation is consistent with a star formation law where the star formation rate per area varies with the gas column density squared. We also propose a simple picture of thermal fragmentation of dense gas in an isothermal, self-gravitating layer as an explanation for the power law. Finally, we briefly compare the star-gas correlation and its implied star formation law with other recent proposed of star formation laws at similar and larger size scales from nearby star-forming regions.

  7. Gas separating

    DOE Patents [OSTI]

    Gollan, Arye

    1988-01-01

    Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing.

  8. Gas separating

    DOE Patents [OSTI]

    Gollan, Arye Z. [Newton, MA

    1990-12-25

    Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing.

  9. Home Performance with ENERGY STAR

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Home Performance with ENERGY STAR 2014 Building Technologies Office Peer Review Ely Jacobsohn, Ely.Jacobsohn@ee.doe.gov Home Performance with ENERGY STAR Program Manager Project Summary: Home Performance with ENERGY STAR Timeline: Key Partners: Start date: 2001 Planned end date: Ongoing Key Milestones 1. Program Action Plan: Jan ͛13 2. D̯χ̯ D̯ν·̼Ϊ̯ι͇ν΄ D͋̽ ·13 3. ͜Σ͇Ϣνχιϴ ΡΪιΙ GιΪϢζ΄ ̯ͧΣ ·14 4. Sponsor Guide (ϭ1΅5)΄ ͱ̯ι ·14 Budget: Total DOE $ to

  10. Neutron skins and neutron stars

    SciTech Connect (OSTI)

    Piekarewicz, J.

    2013-11-07

    The neutron-skin thickness of heavy nuclei provides a fundamental link to the equation of state of neutron-rich matter, and hence to the properties of neutron stars. The Lead Radius Experiment ('PREX') at Jefferson Laboratory has recently provided the first model-independence evidence on the existence of a neutron-rich skin in {sup 208}Pb. In this contribution we examine how the increased accuracy in the determination of neutron skins expected from the commissioning of intense polarized electron beams may impact the physics of neutron stars.

  11. Resolved H I imaging of a population of massive H I-rich galaxies with suppressed star formation

    SciTech Connect (OSTI)

    Lemonias, Jenna J.; Schiminovich, David; Catinella, Barbara; Heckman, Timothy M.; Moran, Sean M.

    2014-07-20

    Despite the existence of well-defined relationships between cold gas and star formation, there is evidence that some galaxies contain large amounts of H I that do not form stars efficiently. By systematically assessing the link between H I and star formation within a sample of galaxies with extremely high H I masses (log M{sub H{sub I}}/M{sub ?} > 10), we uncover a population of galaxies with an unexpected combination of high H I masses and low specific star formation rates that exists primarily at stellar masses greater than log M{sub *}/M{sub ?} ? 10.5. We obtained H I maps of 20 galaxies in this population to understand the distribution of the H I and the physical conditions in the galaxies that could be suppressing star formation in the presence of large quantities of H I. We find that all of the galaxies we observed have low H I surface densities in the range in which inefficient star formation is common. The low H I surface densities are likely the main cause of the low specific star formation rates, but there is also some evidence that active galactic nuclei or bulges contribute to the suppression of star formation. The sample's agreement with the global star formation law highlights its usefulness as a tool for understanding galaxies that do not always follow expected relationships.

  12. Shocks and star formation in Stephan's Quintet. I. Gemini spectroscopy of H?-bright knots

    SciTech Connect (OSTI)

    Konstantopoulos, I. S.; Cluver, M. E.; Appleton, P. N.; Guillard, P.; Trancho, G.; Bastian, N.; Charlton, J. C.; Fedotov, K.; Gallagher, S. C.; Smith, L. J.; Struck, C. J.

    2014-03-20

    We present a Gemini-GMOS spectroscopic study of Hubble Space Telescope (HST)-selected H?-emitting regions in Stephan's Quintet (HCG 92), a nearby compact galaxy group, with the aim of disentangling the processes of shock-induced heating and star formation in its intra-group medium. The ?40 sources are distributed across the system, but most densely concentrated in the ?kiloparsec-long shock region. Their spectra neatly divide them into narrow- and broad-line emitters, and we decompose the latter into three or more emission peaks corresponding to spatial elements discernible in HST imaging. The emission-line ratios of the two populations of H?-emitters confirm their nature as H II regions (90% of the sample) or molecular gas heated by a shock front propagating at ?300 km s{sup 1}. Their redshift distribution reveals interesting three-dimensional structure with respect to gas-phase baryons, with no H II regions associated with shocked gas, no shocked regions in the intruder galaxy NGC 7318B, and a sharp boundary between shocks and star formation. We conclude that star formation is inhibited substantially, if not entirely, in the shock region. Attributing those H II regions projected against the shock to the intruder, we find a lopsided distribution of star formation in this galaxy, reminiscent of pileup regions in models of interacting galaxies. The H? luminosities imply mass outputs, star formation rates, and efficiencies similar to nearby star-forming regions. Two large knots are an exception to this, being comparable in stellar output to the prolific 30 Doradus region. We also examine Stephan's Quintet in the context of compact galaxy group evolution, as a paradigm for intermittent star formation histories in the presence of a rich, X-ray-emitting intra-group medium. All spectra are provided as supplemental materials.

  13. ENERGY STAR Webinar: ENERGY STAR and Green Building Rating Systems

    Office of Energy Efficiency and Renewable Energy (EERE)

    Hosted by the U.S. Environmental Protection Agency's (EPA's) ENERGY STAR, this webinar will help attendees how to use EPA tools and resources to help meet requirements for green building rating systems, such as the U.S. Green Building Council's Leadership in Energy and Environmental Design (LEED), the Green Globes system, and others.

  14. Virginia Natural Gas Number of Gas and Gas Condensate Wells ...

    U.S. Energy Information Administration (EIA) Indexed Site

    Gas and Gas Condensate Wells (Number of Elements) Virginia Natural Gas Number of Gas and Gas Condensate Wells (Number of Elements) Decade Year-0 Year-1 Year-2 Year-3 Year-4 Year-5 ...

  15. IN-SYNC. II. VIRIAL STARS FROM SUBVIRIAL CORES—THE VELOCITY DISPERSION OF EMBEDDED PRE-MAIN-SEQUENCE STARS IN NGC 1333

    SciTech Connect (OSTI)

    Foster, Jonathan B.; Cottaar, Michiel; Meyer, Michael R.; Covey, Kevin R.; Arce, Héctor G.; Nidever, David L.; Stassun, Keivan G.; Tan, Jonathan C.; Da Rio, Nicola; Chojnowski, S. Drew; Majewski, Steven R.; Skrutskie, Michael; Wilson, John C.; Flaherty, Kevin M.; Rebull, Luisa; Zasowski, Gail

    2015-02-01

    The initial velocity dispersion of newborn stars is a major unconstrained aspect of star formation theory. Using near-infrared spectra obtained with the APOGEE spectrograph, we show that the velocity dispersion of young (1-2 Myr) stars in NGC 1333 is 0.92 ± 0.12 km s{sup –1} after correcting for measurement uncertainties and the effect of binaries. This velocity dispersion is consistent with the virial velocity of the region and the diffuse gas velocity dispersion, but significantly larger than the velocity dispersion of the dense, star-forming cores, which have a subvirial velocity dispersion of 0.5 km s{sup –1}. Since the NGC 1333 cluster is dynamically young and deeply embedded, this measurement provides a strong constraint on the initial velocity dispersion of newly formed stars. We propose that the difference in velocity dispersion between stars and dense cores may be due to the influence of a 70 μG magnetic field acting on the dense cores or be the signature of a cluster with initial substructure undergoing global collapse.

  16. UPPER BOUND ON THE FIRST STAR FORMATION HISTORY

    SciTech Connect (OSTI)

    Inoue, Yoshiyuki; Madejski, Grzegorz M.; Tanaka, Yasuyuki T.; Domnguez, Alberto

    2014-02-01

    Our understanding of the nature of the extragalactic background light (EBL) has improved with the recent development of gamma-ray observation techniques. An open subject in the context of the EBL is the reionization epoch, which is an important probe of the formation history of first stars, the so-called Population III (Pop III) stars. Although the mechanisms for the formation of PopIII stars are rather well understood on theoretical grounds, their formation history is still veiled in mystery because of their faintness. To shed light on this matter, we study jointly the gamma-ray opacity of distant objects and the reionization constraints from studies of intergalactic gas. By combining these studies, we obtain a sensitive upper bound on the PopIII star formation rate density of ?-dot {sub ?}(z)<0.01[(1+z)/(1+7.0)]{sup 3.4}(f{sub esc}/0.2){sup ?1}(C/3.0)M{sub ?}yr{sup ?1}Mpc{sup ?3} at z ? 7, where f {sub esc} and C are the escape fraction of ionizing photons from galaxies and the clumping factor of the intergalactic hydrogen gas. This limit is a ?10times tighter constraint compared with previous studies that take into account gamma-ray opacity constraints only. Even if we do not include the current gamma-ray constraints, the results do not change. This is because the detected gamma-ray sources are still at z ? 4.35 where the reionization has already finished.

  17. Cold quark matter in compact stars

    SciTech Connect (OSTI)

    Franzon, B.; Fogaca, D. A.; Navarra, F. S.; Horvath, J. E.

    2013-03-25

    We used an equation of state for the cold quark matter to the study of properties of quark stars. We also discuss the absolute stability of quark matter and compute the mass-radius relation for self-bound stars.

  18. Residential Energy Star Appliance Rebate Program

    Broader source: Energy.gov [DOE]

    Refrigerators and freezers must be installed in homes within the PGE or Pacific Power service territory to qualify.  All Energy Star freezers qualify for the $35 rebate.  Only Energy Star...

  19. Equator Appliance: ENERGY STAR Referral (EZ 3720)

    Broader source: Energy.gov [DOE]

    DOE referred Equator Appliance clothes washer EZ 3720 to EPA, brand manager of the ENERGY STAR program, for appropriate action after DOE testing revealed that the model does not meet ENERGY STAR requirements.

  20. Alliance Star Energy LLC | Open Energy Information

    Open Energy Info (EERE)

    Star Energy LLC Jump to: navigation, search Name: Alliance Star Energy LLC Place: California Phone Number: (619) 574-0527 Outage Hotline: (619) 574-0527 References: EIA Form...

  1. K Star Solar | Open Energy Information

    Open Energy Info (EERE)

    Solar Jump to: navigation, search Name: K-Star Solar Place: New York Product: Long Island-based PV systems installer. References: K-Star Solar1 This article is a stub. You can...

  2. ENERGY STAR Webinar: Portfolio Manager 101

    Broader source: Energy.gov [DOE]

    Hosted by the U.S. Environmental Protection Agency's (EPA's) ENERGY STAR, this webinar will introduce and demonstrate the EPA's ENERGY STAR Portfolio Manager tool. Attendees will learn how to...

  3. Haier: ENERGY STAR Referral (ESA408J)

    Office of Energy Efficiency and Renewable Energy (EERE)

    DOE referred Haier room air conditioner model ESA408J to EPA, brand manager of the ENERGY STAR program, for appropriate action after DOE testing revealed that the model does not meet ENERGY STAR requirements.

  4. LoanSTAR Revolving Loan Program

    Broader source: Energy.gov [DOE]

    Provides an overview of the LoanStar Revolving Loan program. Author: Texas State Energy Conservation Office

  5. The nuclear physics of neutron stars

    SciTech Connect (OSTI)

    Piekarewicz, J.

    2014-05-09

    We explore the unique and fascinating structure of neutron stars. Although neutron stars are of interest in many areas of Physics, our aim is to provide an intellectual bridge between Nuclear Physics and Astrophysics. We argue against the naive perception of a neutron star as a uniform assembly of neutrons packed to enormous densities. Rather, by focusing on the many exotic phases that are speculated to exist in a neutron star, we show how the reality is different and far more interesting.

  6. NuSTAR: Nuclear Spectroscopic Telescope Array

    ScienceCinema (OSTI)

    Craig, Bill

    2014-06-24

    Bill Craig, an astrophysicist at Lawrence Livermore National Laboratory, describes the NASA NuSTAR mission, launched June 13, 2012.

  7. NuSTAR: Nuclear Spectroscopic Telescope Array

    SciTech Connect (OSTI)

    Craig, Bill

    2012-06-13

    Bill Craig, an astrophysicist at Lawrence Livermore National Laboratory, describes the NASA NuSTAR mission, launched June 13, 2012.

  8. ENERGY STAR Webinar: Portfolio Manager 201

    Broader source: Energy.gov [DOE]

    This webinar continues on the U.S. Environmental Protection Agency's (EPA's) new ENERGY STAR Portfolio Manager tool.

  9. Hot Jupiters and cool stars

    SciTech Connect (OSTI)

    Villaver, Eva; Mustill, Alexander J.; Livio, Mario; Siess, Lionel

    2014-10-10

    Close-in planets are in jeopardy, as their host stars evolve off the main sequence (MS) to the subgiant and red giant phases. In this paper, we explore the influences of the stellar mass (in the range 1.5-2 M {sub ☉}), mass-loss prescription, planet mass (from Neptune up to 10 Jupiter masses), and eccentricity on the orbital evolution of planets as their parent stars evolve to become subgiants and red giants. We find that planet engulfment along the red giant branch is not very sensitive to the stellar mass or mass-loss rates adopted in the calculations, but quite sensitive to the planetary mass. The range of initial separations for planet engulfment increases with decreasing mass-loss rates or stellar masses and increasing planetary masses. Regarding the planet's orbital eccentricity, we find that as the star evolves into the red giant phase, stellar tides start to dominate over planetary tides. As a consequence, a transient population of moderately eccentric close-in Jovian planets is created that otherwise would have been expected to be absent from MS stars. We find that very eccentric and distant planets do not experience much eccentricity decay, and that planet engulfment is primarily determined by the pericenter distance and the maximum stellar radius.

  10. ENHANCED ACCRETION RATES OF STARS ON SUPERMASSIVE BLACK HOLES BY STAR-DISK INTERACTIONS IN GALACTIC NUCLEI

    SciTech Connect (OSTI)

    Just, Andreas; Yurin, Denis; Makukov, Maxim; Berczik, Peter; Omarov, Chingis; Spurzem, Rainer; Vilkoviskij, Emmanuil Y.

    2012-10-10

    We investigate the dynamical interaction of a central star cluster surrounding a supermassive black hole (SMBH) and a central accretion disk (AD). The dissipative force acting on stars in the disk leads to an enhanced mass flow toward the SMBH and to an asymmetry in the phase space distribution due to the rotating AD. The AD is considered as a stationary Keplerian rotating disk, which is vertically extended in order to employ a fully self-consistent treatment of stellar dynamics including the dissipative force originating from star-gas ram pressure effects. The stellar system is treated with a direct high-accuracy N-body integration code. A star-by-star representation, desirable in N-body simulations, cannot be extended to real particle numbers yet. Hence, we carefully discuss the scaling behavior of our model with regard to particle number and tidal accretion radius. The main idea is to find a family of models for which the ratio of two-body relaxation time and dissipation time (for kinetic energy of stellar orbits) is constant, which then allows us to extrapolate our results to real parameters of galactic nuclei. Our model is derived from basic physical principles and as such it provides insight into the role of physical processes in galactic nuclei, but it should be regarded as a first step toward more realistic and more comprehensive simulations. Nevertheless, the following conclusions appear to be robust: the star accretion rate onto the AD and subsequently onto the SMBH is enhanced by a significant factor compared to purely stellar dynamical systems neglecting the disk. This process leads to enhanced fueling of central disks in active galactic nuclei (AGNs) and to an enhanced rate of tidal stellar disruptions. Such disruptions may produce electromagnetic counterparts in the form of observable X-ray flares. Our models improve predictions for their rates in quiescent galactic nuclei. We do not yet model direct stellar collisions in the gravitational potential

  11. A NEW METHOD FOR OBTAINING THE STAR FORMATION LAW IN GALAXIES

    SciTech Connect (OSTI)

    Heiner, Jonathan S.; Allen, Ronald J.; Van der Kruit, Pieter C.

    2010-08-20

    We present a new observational method to evaluate the exponent of the star formation law as initially formulated by Schmidt, i.e., the power-law expression assumed to relate the rate of star formation in a volume of space to the local total gas volume density present there. Total volume densities in the gas clouds surrounding an OB association are determined with a simple model which considers the atomic hydrogen as a photodissociation product on the cloud surfaces. The photodissociating photon flux incident on the cloud is computed from the far-UV luminosity of the OB association and the geometry. As an example, we have applied this 'PDR Method' to a sample of star-forming regions in M33 using Very Large Array (VLA) 21 cm data for the H I and Galaxy Evolution Explorer (GALEX) imagery in the far-UV. With these two observables, our approach provides an estimate of the total volume density of hydrogen (atomic + molecular) in the gas clouds surrounding the young star cluster. A graph in logarithmic coordinates of the cluster UV luminosity versus the total density in the surrounding gas provides a direct measure of the exponent of the star formation law. However, we show that this plot is severely affected by observational selection, which renders large areas of the diagram inaccessible to the data. An ordinary least-squares regression fit to a straight line, therefore, gives a strongly biased result. In the present case, the slope of such a fit primarily reflects the boundary defined when the 21 cm line becomes optically thick and is no longer a reliable measure of the H I column density. We use a maximum likelihood statistical approach which can deal with truncated and skewed data, and also takes account of the large uncertainties in the total gas densities which we derive. The exponent we obtain for the Schmidt law in M33 is 1.4 {+-} 0.2.

  12. Multi-wavelength studies of spectacular ram-pressure stripping of a galaxy. II. Star formation in the tail

    SciTech Connect (OSTI)

    Yagi, Masafumi; Gu, Liyi; Nakazawa, Kazuhiro; Makishima, Kazuo; Fujita, Yutaka; Akahori, Takuya; Hattori, Takashi; Yoshida, Michitoshi

    2013-12-01

    With multiband photometric data in public archives, we detected four intracluster star-forming regions in the Virgo Cluster. Two of them were at a projected distance of 35 kpc from NGC 4388 and the other two were 66 kpc away. Our new spectroscopic observations revealed that their recessional velocities were comparable to the ram-pressure-stripped tail of NGC 4388 and confirmed the association. The stellar mass of the star-forming regions ranged from 10{sup 4} to 10{sup 4.5} M {sub ?} except for that of the faintest one, which was <10{sup 3} M {sub ?}. The metallicity was comparable to a solar abundance and the age of the stars was ?10{sup 6.8} yr. Their young stellar age meant that the star formation should have started after the gas was stripped from NGC 4388. This implied in situ condensation of the stripped gas. We also found that two star-forming regions were located near the leading edge of a filamentary dark cloud. The extinction of the filament was smaller than that derived from the Balmer decrement of the star-forming regions, implying that the dust in the filament would be locally dense around the star-forming regions.

  13. Gas magnetometer

    DOE Patents [OSTI]

    Walker, Thad Gilbert; Lancor, Brian Robert; Wyllie, Robert

    2016-05-03

    Measurement of a precessional rate of a gas, such as an alkali gas, in a magnetic field is made by promoting a non-uniform precession of the gas in which substantially no net magnetic field affects the gas during a majority of the precession cycle. This allows sensitive gases that would be subject to spin-exchange collision de-phasing to be effectively used for extremely sensitive measurements in the presence of an environmental magnetic field such as the Earth's magnetic field.

  14. Gas separating

    DOE Patents [OSTI]

    Gollan, A.

    1988-03-29

    Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing. 3 figs.

  15. Gas separating

    DOE Patents [OSTI]

    Gollan, A.Z.

    1990-12-25

    Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing. 3 figs.

  16. Natural Gas

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

    Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, ... Grid Integration & Advanced Inverters Materials & Fabrication Microsystems Enabled ...

  17. Shifter image of STAR SL13a

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

    Shifter image of STAR SL13a Shifter image of STAR SL13a WORK-IN PROGRESS A demonstrator STAR Shifter image is available for testing at Edison. At this time there is only one STAR image available for starver=SL13a. To deploy it on a single 32 core Cori node for 30 minutes execute the following sequence of commands (marked in bold) /* login to Edison, keep graphics port open */ my-laptop$ ssh -A -X edison.nersc.gov /* load needed module */ edison06:~>$ module load shifter /* verify you see STAR

  18. FIRST INVESTIGATION OF THE COMBINED IMPACT OF IONIZING RADIATION AND MOMENTUM WINDS FROM A MASSIVE STAR ON A SELF-GRAVITATING CORE

    SciTech Connect (OSTI)

    Ngoumou, Judith; Hubber, David; Dale, James E.; Burkert, Andreas

    2015-01-01

    Massive stars shape the surrounding interstellar matter (ISM) by emitting ionizing photons and ejecting material through stellar winds. To study the impact of the momentum from the wind of a massive star on the surrounding neutral or ionized material, we implemented a new HEALPix-based momentum-conserving wind scheme in the smoothed particle hydrodynamics (SPH) code SEREN. A qualitative study of the impact of the feedback from an O7.5-like star on a self-gravitating sphere shows that on its own, the transfer of momentum from a wind onto cold surrounding gas has both a compressing and dispersing effect. It mostly affects gas at low and intermediate densities. When combined with a stellar source's ionizing ultraviolet (UV) radiation, we find the momentum-driven wind to have little direct effect on the gas. We conclude that during a massive star's main sequence, the UV ionizing radiation is the main feedback mechanism shaping and compressing the cold gas. Overall, the wind's effects on the dense gas dynamics and on the triggering of star formation are very modest. The structures formed in the ionization-only simulation and in the combined feedback simulation are remarkably similar. However, in the combined feedback case, different SPH particles end up being compressed. This indicates that the microphysics of gas mixing differ between the two feedback simulations and that the winds can contribute to the localized redistribution and reshuffling of gas.

  19. Ultrafaint dwarfs—star formation and chemical evolution in the smallest galaxies

    SciTech Connect (OSTI)

    Webster, David; Bland-Hawthorn, Joss; Sutherland, Ralph

    2014-11-20

    In earlier work, we showed that a dark matter halo with a virial mass of 10{sup 7} M {sub ☉} can retain a major part of its baryons in the face of the pre-ionization phase and supernova (SN) explosion from a 25 M {sub ☉} star. Here, we expand on the results of that work, investigating the star formation and chemical evolution of the system beyond the first SN. In a galaxy with a mass M {sub vir} = 10{sup 7} M {sub ☉}, sufficient gas is retained by the potential for a second period of star formation to occur. The impact of a central explosion is found to be much stronger than that of an off-center explosion both in blowing out the gas and in enriching it, as in the off-center case most of the SN energy and metals escape into the intergalactic medium. We model the star formation and metallicity, given the assumption that stars form for 100, 200, 400, and 600 Myr, and discuss the results in the context of recent observations of very low-mass galaxies. We show that we can account for most features of the observed relationship between [α/Fe] and [Fe/H] in ultra-faint dwarf galaxies with the assumption that the systems formed at a low mass, rather than being remnants of much larger systems.

  20. Effects of spiral arms on star formation in nuclear rings of barred-spiral galaxies

    SciTech Connect (OSTI)

    Seo, Woo-Young; Kim, Woong-Tae E-mail: wkim@astro.snu.ac.kr

    2014-09-01

    We use hydrodynamic simulations to study the effect of spiral arms on the star formation rate (SFR) in nuclear rings of barred-spiral galaxies. We find that spiral arms can be an efficient means of gas transport from the outskirts to the central parts, provided that the arms are rotating slower than the bar. While the ring star formation in models with no arms or corotating arms is active only during around the bar growth phase, arm-driven gas accretion both significantly enhances and prolongs the ring star formation in models with slow-rotating arms. The arm-enhanced SFR is larger by a factor of ?3-20 than in the no-arm model, with larger values corresponding to stronger and slower arms. Arm-induced mass inflows also make dust lanes stronger. Nuclear rings in slow-arm models are ?45% larger than in the no-arm counterparts. Star clusters that form in a nuclear ring exhibit an age gradient in the azimuthal direction only when the SFR is small, whereas no notable age gradient is found in the radial direction for models with arm-induced star formation.

  1. The mass spectrum of the first stars

    SciTech Connect (OSTI)

    Susa, Hajime; Tominaga, Nozomu; Hasegawa, Kenji

    2014-09-01

    We perform cosmological hydrodynamics simulations with non-equilibrium primordial chemistry to obtain 59 minihalos that host first stars. The obtained minihalos are used as the initial conditions of local three-dimensional radiation hydrodynamics simulations to investigate the formation of the first stars. We find that two-thirds of the minihalos host multiple stars, while the other third has single stars. The mass of the stars found in our simulations are in the range of 1 M {sub ☉} ≲ M ≲ 300 M {sub ☉}, peaking at several× 10 M {sub ☉}. Most of the very massive stars of ≳ 140 M {sub ☉} are born as single stars, although not all of the single stars are very massive. We also find a few stars of ≲ 1 M {sub ☉} that are kicked by the gravitational three body interactions to the position distant from the center of mass. The frequency that a star forming minihalo contains a binary system is ∼50%. We also investigate the abundance pattern of the stellar remnants by summing up the contributions from the first stars in the simulations. Consequently, the pattern is compatible with that of the low metallicity damped Lyα systems or the extremely metal-poor (EMP) stars, if the mass spectrum obtained in our experiment is shifted to the low mass side by 0.2 dex. If we consider the case that an EMP star is born in the remnant of the individual minihalo without mixing with others, the chemical signature of the pair instability supernova is more prominent, because most of them are born as single stars.

  2. POSSIBLE ORIGIN OF THE G2 CLOUD FROM THE TIDAL DISRUPTION OF A KNOWN GIANT STAR BY SGR A*

    SciTech Connect (OSTI)

    Guillochon, James; Loeb, Abraham; MacLeod, Morgan; Ramirez-Ruiz, Enrico

    2014-05-10

    The discovery of the gas cloud G2 on a near-radial orbit about SgrA* has prompted much speculation on its origin. In this Letter, we propose that G2 formed out of the debris stream produced by the removal of mass from the outer envelope of a nearby giant star. We perform hydrodynamical simulations of the returning tidal debris stream with cooling and find that the stream condenses into clumps that fall periodically onto SgrA*. We propose that one of these clumps is the observed G2 cloud, with the rest of the stream being detectable at lower Br? emissivity along a trajectory that would trace from G2 to the star that was partially disrupted. By simultaneously fitting the orbits of S2, G2, and ?2000 candidate stars, and by fixing the orbital plane of each candidate star to G2 (as is expected for a tidal disruption), we find that several stars have orbits that are compatible with the notion that one of them was tidally disrupted to produce G2. If one of these stars were indeed disrupted, it last encountered SgrA* hundreds of years ago and has likely encountered SgrA* repeatedly. However, while these stars are compatible with the giant disruption scenario given their measured positions and proper motions, their radial velocities are currently unknown. If one of these stars' radial velocity is measured to be compatible with a disruptive orbit, it would strongly suggest that its disruption produced G2.

  3. STAR CLUSTER DISRUPTION IN THE STARBURST GALAXY MESSIER 82

    SciTech Connect (OSTI)

    Li, Shuo; Li, Chengyuan; De Grijs, Richard; Anders, Peter

    2015-01-01

    Using high-resolution, multiple-passband Hubble Space Telescope images spanning the entire optical/near-infrared wavelength range, we obtained a statistically complete U-band-selected sample of 846 extended star clusters across the disk of the nearby starburst galaxy M82. Based on a careful analysis of the clusters' spectral energy distributions, we determined their galaxy-wide age and mass distributions. The M82 clusters exhibit three clear peaks in their age distribution, thus defining relatively young, log (t yr{sup 1}) ? 7.5, intermediate-age, log (t yr{sup 1}) in [7.5, 8.5], and old samples, log (t yr{sup 1}) ? 8.5. Comparison of the completeness-corrected mass distributions offers a firm handle on the galaxy's star cluster disruption history. The most massive star clusters in the young and old samples are (almost) all concentrated in the most densely populated central region, while the intermediate-age sample's most massive clusters are more spatially dispersed, which may reflect the distribution of the highest-density gas throughout the galaxy's evolutionary history, combined with the solid-body nature of the galaxy's central region.

  4. star formation rates of z > 1 galaxy clusters in the IRAC shallow cluster survey

    SciTech Connect (OSTI)

    Zeimann, Gregory R.; Stanford, S. A.; Brodwin, Mark; Gonzalez, Anthony H.; Mancone, Conor; Snyder, Gregory F.; Stern, Daniel; Eisenhardt, Peter; Dey, Arjun; Moustakas, John

    2013-12-20

    We present Hubble Space Telescope near-IR spectroscopy for 18 galaxy clusters at 1.0 star formation rates within a projected radius of 500 kpc, and many of our clusters (∼60%) have significant levels of star formation within a projected radius of 200 kpc. A stacking analysis reveals that dust reddening in these star-forming galaxies is positively correlated with stellar mass and may be higher in the field than the cluster at a fixed stellar mass. This may indicate a lower amount of gas in star-forming cluster galaxies than in the field population. Also, Hα equivalent widths of star-forming galaxies in the cluster environment are still suppressed below the level of the field. This suppression is most significant for lower mass galaxies (log M {sub *} < 10.0 M {sub ☉}). We therefore conclude that environmental effects are still important at 1.0 star-forming galaxies in galaxy clusters with log M {sub *} ≲ 10.0 M {sub ☉}.

  5. YOUNG STARS IN AN OLD BULGE: A NATURAL OUTCOME OF INTERNAL EVOLUTION IN THE MILKY WAY

    SciTech Connect (OSTI)

    Ness, M.; Debattista, Victor P.; Cole, D. R.; Bensby, T.; Feltzing, S.; Roškar, R.; Johnson, J. A.; Freeman, K.

    2014-06-01

    The center of our disk galaxy, the Milky Way, is dominated by a boxy/peanut-shaped bulge. Numerous studies of the bulge based on stellar photometry have concluded that the bulge stars are exclusively old. The perceived lack of young stars in the bulge strongly constrains its likely formation scenarios, providing evidence that the bulge is a unique population that formed early and separately from the disk. However, recent studies of individual bulge stars using the microlensing technique have reported that they span a range of ages, emphasizing that the bulge may not be a monolithic structure. In this Letter we demonstrate that the presence of young stars that are located predominantly nearer to the plane is expected for a bulge that has formed from the disk via dynamical instabilities. Using an N-body+ smoothed particle hydrodynamics simulation of a disk galaxy forming out of gas cooling inside a dark matter halo and forming stars, we find a qualitative agreement between our model and the observations of younger metal-rich stars in the bulge. We are also able to partially resolve the apparent contradiction in the literature between results that argue for a purely old bulge population and those that show a population comprised of a range in ages; the key is where to look.

  6. REVISITING THE FIRST GALAXIES: THE EFFECTS OF POPULATION III STARS ON THEIR HOST GALAXIES

    SciTech Connect (OSTI)

    Muratov, Alexander L.; Gnedin, Oleg Y.; Zemp, Marcel [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Gnedin, Nickolay Y., E-mail: muratov@umich.edu [Particle Astrophysics Center, Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States)

    2013-08-01

    We revisit the formation and evolution of the first galaxies using new hydrodynamic cosmological simulations with the adaptive refinement tree code. Our simulations feature a recently developed model for H{sub 2} formation and dissociation, and a star formation recipe that is based on molecular rather than atomic gas. Here, we develop and implement a recipe for the formation of metal-free Population III (Pop III) stars in galaxy-scale simulations that resolve primordial clouds with sufficiently high density. We base our recipe on the results of prior zoom-in simulations that resolved the protostellar collapse in pre-galactic objects. We find the epoch during which Pop III stars dominated the energy and metal budget of the first galaxies to be short-lived. Galaxies that host Pop III stars do not retain dynamical signatures of their thermal and radiative feedback for more than 10{sup 8} years after the lives of the stars end in pair-instability supernovae, even when we consider the maximum reasonable efficiency of the feedback. Though metals ejected by the supernovae can travel well beyond the virial radius of the host galaxy, they typically begin to fall back quickly, and do not enrich a large fraction of the intergalactic medium. Galaxies with a total mass in excess of 3 Multiplication-Sign 10{sup 6} M{sub Sun} re-accrete most of their baryons and transition to metal-enriched Pop II star formation.

  7. THE STAR-FORMATION RELATION FOR REGIONS IN THE GALACTIC PLANE: THE EFFECT OF SPATIAL RESOLUTION

    SciTech Connect (OSTI)

    Vutisalchavakul, Nalin; Evans II, Neal J.; Battersby, Cara

    2014-12-20

    We examined the relations between molecular gas surface density and star-formation rate surface density in an 11deg{sup 2} region of the Galactic plane. Dust continua at 1.1mm from the Bolocam Galactic Plane Survey and 22 ?m emission from the Wide-field Infrared Survey Explorer (WISE) all-sky survey were used as tracers of molecular gas and the star-formation rate, respectively, across the Galactic longitude of 31.5 ? l ? 20.5 and Galactic latitude of 0.5 ? b ? 0.5. The relation was studied over a range of resolutions from 33'' to 20' by convolving images to larger scales. The pixel-by-pixel correlation between 1.1mm and 22 ?m increases rapidly at small scales and levels off at the scale of 5'-8'. We studied the star-formation relation based on a pixel-by-pixel analysis and on an analysis of the 1.1mm and 22 ?m peaks. The star-formation relation was found to be nearly linear with no significant changes in the form of the relation across all spatial scales, and it lies above the extragalactic relation from Kennicutt. The average gas-depletion time is ?200 Myr and does not change significantly at different scales, but the scatter in the depletion time decreases as the scale increases.

  8. Neutron stars and strange stars in the chiral SU(3) quark mean field model

    SciTech Connect (OSTI)

    P. Wang; S. Lawley; D. B. Leinweber; A. W. Thomas; A. G. Williams

    2005-06-01

    We investigate the equations of state for pure neutron matter and strange hadronic matter in {beta}-equilibrium, including {Lambda}, {Sigma} and {Xi} hyperons. The masses and radii of pure neutron stars and strange hadronic stars are obtained. For a pure neutron star, the maximum mass is about 1.8 M{sub sun}, while for a strange hadronic star, the maximum mass is around 1.45M{sub sun}. The typical radii of pure neutron stars and strange hadronic stars are about 11.0-12.3 km and 10.7-11.7 km, respectively.

  9. The diskmass survey. VIII. On the relationship between disk stability and star formation

    SciTech Connect (OSTI)

    Westfall, Kyle B.; Verheijen, Marc A. W.; Andersen, David R.; Bershady, Matthew A.; Martinsson, Thomas P. K.; Swaters, Robert A.

    2014-04-10

    We study the relationship between the stability level of late-type galaxy disks and their star-formation activity using integral-field gaseous and stellar kinematic data. Specifically, we compare the two-component (gas+stars) stability parameter from Romeo and Wiegert (Q {sub RW}), incorporating stellar kinematic data for the first time, and the star-formation rate estimated from 21 cm continuum emission. We determine the stability level of each disk probabilistically using a Bayesian analysis of our data and a simple dynamical model. Our method incorporates the shape of the stellar velocity ellipsoid (SVE) and yields robust SVE measurements for over 90% of our sample. Averaging over this subsample, we find a meridional shape of ?{sub z}/?{sub R}=0.51{sub ?0.25}{sup +0.36} for the SVE and, at 1.5 disk scale lengths, a stability parameter of Q {sub RW} = 2.0 0.9. We also find that the disk-averaged star-formation-rate surface density ( ?-dot {sub e,?}) is correlated with the disk-averaged gas and stellar mass surface densities (? {sub e,} {sub g} and ? {sub e,} {sub *}) and anti-correlated with Q {sub RW}. We show that an anti-correlation between ?-dot {sub e,?} and Q {sub RW} can be predicted using empirical scaling relations, such that this outcome is consistent with well-established statistical properties of star-forming galaxies. Interestingly, ?-dot {sub e,?} is not correlated with the gas-only or star-only Toomre parameters, demonstrating the merit of calculating a multi-component stability parameter when comparing to star-formation activity. Finally, our results are consistent with the Ostriker et al. model of self-regulated star-formation, which predicts ?-dot {sub e,?}/?{sub e,g}??{sub e,?}{sup 1/2}. Based on this and other theoretical expectations, we discuss the possibility of a physical link between disk stability level and star-formation rate in light of our empirical results.

  10. ON THE INITIAL MASS FUNCTION OF LOW-METALLICITY STARS: THE IMPORTANCE OF DUST COOLING

    SciTech Connect (OSTI)

    Dopcke, Gustavo [Member of the International Max Planck Research School for Astronomy and Cosmic Physics at the University of Heidelberg, IMPRS-HD, Germany. (Germany)] [Member of the International Max Planck Research School for Astronomy and Cosmic Physics at the University of Heidelberg, IMPRS-HD, Germany. (Germany); Glover, Simon C. O.; Clark, Paul C.; Klessen, Ralf S., E-mail: gustavo@uni-hd.de [Zentrum fuer Astronomie, Institut fuer Theoretische Astrophysik, Universitaet Heidelberg, Albert-Ueberle-Str. 2, D-69120 Heidelberg (Germany)

    2013-04-01

    The first stars to form in the universe are believed to have distribution of masses biased toward massive stars. This contrasts with the present-day initial mass function, which has a predominance of stars with masses lower than 1 M{sub Sun }. Therefore, the mode of star formation must have changed as the universe evolved. Such a transition is attributed to a more efficient cooling provided by increasing metallicity. Especially dust cooling can overcome the compressional heating, which lowers the gas temperature thus increasing its instability to fragmentation. The purpose of this paper is to verify if dust cooling can efficiently cool the gas, and enhance the fragmentation of gas clouds at the early stages of the universe. To confirm that, we calculate a set of hydrodynamic simulations that include sink particles, which represent contracting protostars. The thermal evolution of the gas during the collapse is followed by making use of a primordial chemical network and also a recipe for dust cooling. We model four clouds with different amounts of metals (10{sup -4}, 10{sup -5}, 10-6 Z{sub Sun }, and 0), and analyze how this property affect the fragmentation of star-forming clouds. We find evidence for fragmentation in all four cases, and hence conclude that there is no critical metallicity below which fragmentation is impossible. Nevertheless, there is a clear change in the behavior of the clouds at Z {approx}< 10{sup -5} Z{sub Sun }, caused by the fact that at this metallicity, fragmentation takes longer to occur than accretion, leading to a flat mass function at lower metallicities.

  11. Storage and Assay of Tritium in STAR

    SciTech Connect (OSTI)

    Longhurst, Glen R.; Anderl, Robert A.; Pawelko, Robert J.; Stoots, Carl J.

    2005-07-15

    The Safety and Tritium Applied Research (STAR) facility at the Idaho National Engineering and Environmental Laboratory (INEEL) is currently being commissioned to investigate tritium-related safety questions for fusion and other technologies. The tritium inventory for the STAR facility will be maintained below 1.5 g to avoid the need for STAR to be classified as a Category 3 nuclear facility. A key capability in successful operation of the STAR facility is the ability to receive, inventory, and dispense tritium to the various experiments underway there. The system central to that function is the Tritium Storage and Assay System (SAS).The SAS has four major functions: (1) receiving and holding tritium, (2) assaying, (3) dispensing, and (4) purifying hydrogen isotopes from non-hydrogen species.This paper describes the design and operation of the STAR SAS and the procedures used for tritium accountancy in the STAR facility.

  12. EPA ENERGY STAR Webinar: How to Apply for the ENERGY STAR

    Broader source: Energy.gov [DOE]

    Join us to learn about applying for ENERGY STAR Certification in Portfolio Manager. Understand the value of the ENERGY STAR certification, see the step-by-step process of applying, and gain tips to...

  13. EPA ENERGY STAR Webinar: How to Apply for the ENERGY STAR Certification

    Broader source: Energy.gov [DOE]

    Join us to learn about applying for ENERGY STAR Certification in Portfolio Manager. Understand the value of the ENERGY STAR certification, see the step-by-step process of applying, and gain tips to...

  14. Home Performance with ENERGY STAR-- Webinar Slides

    Broader source: Energy.gov [DOE]

    "Existing Homes Efficiency – If You Want BetterBuildings – Go with Home Performance with ENERGY STAR," webinar slides from the U.S. Department of Energy.

  15. Rapid cooling and structure of neutron stars

    SciTech Connect (OSTI)

    Van Riper, K.A.; Lattimer, J.M.

    1992-07-01

    This report discusses the following topics on neutron stars: direct URCA neutrino emission; thermal evolution models; analytic model for diffusion through the crust; and core superfluidity. (LSP).

  16. Rapid cooling and structure of neutron stars

    SciTech Connect (OSTI)

    Van Riper, K.A. ); Lattimer, J.M. . Dept. of Earth and Space Sciences)

    1992-01-01

    This report discusses the following topics on neutron stars: direct URCA neutrino emission; thermal evolution models; analytic model for diffusion through the crust; and core superfluidity. (LSP).

  17. Energy Star Rebate Finder | Open Energy Information

    Open Energy Info (EERE)

    Rebate Finder Jump to: navigation, search Tool Summary LAUNCH TOOL Name: Energy Star Rebate Finder AgencyCompany Organization: United States Environmental Protection Agency...

  18. William Fowler and Elements in the Stars

    Office of Scientific and Technical Information (OSTI)

    ... Integrated Flux Distributions in Neutron Capture in Stars, DOE Technical Report, September 23, 1965 Helium (3) Rich Solar Flares, DOE Technical Report, May 3, 1977 Top Additional ...

  19. Reading Municipal Light Department - Residential Energy Star...

    Broader source: Energy.gov (indexed) [DOE]

    Pumps Air conditioners Programmable Thermostats Other EE Maximum Rebate One rebate per Energy Star appliance or two rebates on the purchase of programmable thermostats Program...

  20. Star Energy Systems | Open Energy Information

    Open Energy Info (EERE)

    Systems Jump to: navigation, search Name: Star Energy Systems Place: Ahmedabad, Gujarat, India Zip: 380 009 Sector: Solar Product: Solar PV product distributor. Coordinates:...

  1. Green Star Alternative Energy | Open Energy Information

    Open Energy Info (EERE)

    Alternative Energy Jump to: navigation, search Name: Green Star Alternative Energy Place: San Diego, California Zip: 92108 Sector: Wind energy Product: A US-based wind energy...

  2. Blue Star Energy Services | Open Energy Information

    Open Energy Info (EERE)

    Services Jump to: navigation, search Name: Blue Star Energy Services Place: Illinois Phone Number: 866-258-3782 Website: www.aepenergy.com Twitter: @aepenergy Facebook: https:...

  3. Star, Idaho: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    Star, Idaho: Energy Resources Jump to: navigation, search Equivalent URI DBpedia Coordinates 43.6921071, -116.4934631 Show Map Loading map... "minzoom":false,"mappingservice":...

  4. Green Star Energy LLC | Open Energy Information

    Open Energy Info (EERE)

    LLC Jump to: navigation, search Name: Green Star Energy LLC Place: Houston, Texas Zip: 77002 Product: Houston-based producer of sugar cane processed ethanol, with additional...

  5. RegenaStar | Open Energy Information

    Open Energy Info (EERE)

    navigation, search Name: RegenaStar Place: Pune, Maharashtra, India Product: Pune-based joint venture between Regenatec and Cleanstar that focuses on jatropha cultivation for...

  6. STAR FORMATION ACTIVITY IN THE GALACTIC H II COMPLEX S255-S257

    SciTech Connect (OSTI)

    Ojha, D. K.; Ghosh, S. K.; Samal, M. R.; Pandey, A. K.; Sharma, Saurabh; Bhatt, B. C.; Tamura, M.; Mohan, V.; Zinchenko, I.

    2011-09-10

    We present results on the star formation activity of an optically obscured region containing an embedded cluster (S255-IR) and molecular gas between two evolved H II regions, S255 and S257. We have studied the complex using optical and near-infrared (NIR) imaging, optical spectroscopy, and radio continuum mapping at 15 GHz, along with Spitzer-IRAC results. We found that the main exciting sources of the evolved H II regions S255 and S257 and the compact H II regions associated with S255-IR are of O9.5-B3 V nature, consistent with previous observations. Our NIR observations reveal 109 likely young stellar object (YSO) candidates in an area of {approx}4.'9 x 4.'9 centered on S255-IR, which include 69 new YSO candidates. To see the global star formation, we constructed the V - I/V diagram for 51 optically identified IRAC YSOs in an area of {approx}13' x 13' centered on S255-IR. We suggest that these YSOs have an approximate age between 0.1 and 4 Myr, indicating a non-coeval star formation. Using spectral energy distribution models, we constrained physical properties and evolutionary status of 31 and 16 YSO candidates outside and inside the gas ridge, respectively. The models suggest that the sources associated with the gas ridge are younger (mean age {approx}1.2 Myr) than the sources outside the gas ridge (mean age {approx}2.5 Myr). The positions of the young sources inside the gas ridge at the interface of the H II regions S255 and S257 favor a site of induced star formation.

  7. TURBOVELOCITY STARS: KICKS RESULTING FROM THE TIDAL DISRUPTION OF SOLITARY STARS

    SciTech Connect (OSTI)

    Manukian, Haik; Guillochon, James; Ramirez-Ruiz, Enrico; O'Leary, Ryan M.

    2013-07-10

    The centers of most known galaxies host supermassive black holes (SMBHs). In orbit around these black holes are a centrally concentrated distribution of stars, both in single and in binary systems. Occasionally, these stars are perturbed onto orbits that bring them close to the SMBH. If the star is in a binary system, the three-body interaction with the SMBH can lead to large changes in orbital energy, depositing one of the two stars on a tightly-bound orbit, and its companion into a hyperbolic orbit that may escape the galaxy. In this Letter, we show that the disruption of solitary stars can also lead to large positive increases in orbital energy. The kick velocity depends on the amount of mass the star loses at pericenter, but not on the ratio of black hole to stellar mass, and are at most the star's own escape velocity. We find that these kicks are usually too small to result in the ejection of stars from the Milky Way, but can eject the stars from the black hole's sphere of influence, reducing their probability of being disrupted again. We estimate that {approx} 10{sup 5} stars, {approx} 1% of all stars within 10 pc of the galactic center, are likely to have had mass removed by the central black hole through tidal interaction, and speculate that these 'turbovelocity' stars will at first be redder, but eventually bluer, and always brighter than their unharassed peers.

  8. Spectrometer for Sky-Scanning Sun-Tracking Atmospheric Research (4STAR): Instrument Technology

    SciTech Connect (OSTI)

    Dunagan, Stephen; Johnson, Roy; Zavaleta, Jhony; Russell, P. B.; Schmid, Beat; Flynn, Connor J.; Redemann, Jens; Shinozuka, Yohei; Livingston, J.; Segal Rozenhaimer, Michal

    2013-08-06

    The Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR) combines airborne sun tracking and sky scanning with diffraction spectroscopy, to improve knowledge of atmospheric constituents and their links to air-pollution/climate. Direct beam hyper-spectral measurement of optical depth improves retrievals of gas constituents and determination of aerosol properties. Sky scanning enhances retrievals of aerosol type and size distribution. 4STAR measurements will tighten the closure between satellite and ground-based measurements. 4STAR incorporates a modular sun-tracking/ sky-scanning optical head with fiber optic signal transmission to rack mounted spectrometers, permitting miniaturization of the external optical head, and future detector evolution. Technical challenges include compact optical collector design, radiometric dynamic range and stability, and broad spectral coverage. Test results establishing the performance of the instrument against the full range of operational requirements are presented, along with calibration, engineering flight test, and scientific field campaign data and results.

  9. THE GALEX NEARBY YOUNG-STAR SURVEY

    SciTech Connect (OSTI)

    Rodriguez, David R.; Faherty, Jacqueline K.; Zuckerman, B.; Kastner, Joel H.; Bessell, M. S.; Murphy, Simon J.

    2013-09-10

    We describe a method that exploits data from the Galaxy Evolution Explorer (GALEX) ultraviolet and Wide-field Infrared Survey Explorer and Two Micron All Sky Survey infrared source catalogs, combined with proper motions and empirical pre-main sequence isochrones, to identify candidate nearby, young, low-mass stars. Applying our method across the full GALEX-covered sky, we identify 2031 mostly M-type stars that, for an assumed age of 10 (100) Myr, all lie within {approx}150 ({approx}90) pc of Earth. The distribution of M spectral subclasses among these {approx}2000 candidate young stars peaks sharply in the range M3-M4; these subtypes constitute 50% of the sample, consistent with studies of the M star population in the immediate solar neighborhood. We focus on a subset of 58 of these candidate young M stars in the vicinity of the Tucana-Horologium association. Only 20 of these 58 candidates were detected in the ROSAT All-Sky X-ray Survey-reflecting the greater sensitivity of GALEX for the purposes of identifying active nearby, young stars, particularly for stars of type M4 and later. Based on statistical analysis of the kinematics and/or spectroscopic followup of these 58 M stars, we find that 50% (29 stars) indeed have properties consistent with Tuc-Hor membership, while 12 are potential new members of the Columba association, and 2 may be AB Dor moving group members. Hence, {approx}75% of our initial subsample of 58 candidates are likely members of young (age {approx} 10-40 Myr) stellar moving groups within 100 pc, verifying that the stellar color- and kinematics-based selection algorithms described here can be used to efficiently isolate nearby, young, low-mass objects from among the field star population. Future studies will focus on characterizing additional subsamples selected from among this list of candidate nearby, young M stars.

  10. MHK Technologies/WaveStar | Open Energy Information

    Open Energy Info (EERE)

    to the MHK database homepage WaveStar.jpg Technology Profile Primary Organization Wave Star Energy Project(s) where this technology is utilized *MHK ProjectsWave Star Energy 1...

  11. The ACS LCID project. X. the star formation history of IC 1613: Revisiting the over-cooling problem

    SciTech Connect (OSTI)

    Skillman, Evan D.; Hidalgo, Sebastian L.; Monelli, Matteo; Gallart, Carme; Aparicio, Antonio E-mail: shidalgo@iac.es E-mail: carme@iac.es [Instituto de Astrofsica de Canarias, Va Lctea s and others

    2014-05-01

    We present an analysis of the star formation history (SFH) of a field near the half-light radius in the Local Group dwarf irregular galaxy IC 1613 based on deep Hubble Space Telescope Advanced Camera for Surveys imaging. Our observations reach the oldest main sequence turn-off, allowing a time resolution at the oldest ages of ?1 Gyr. Our analysis shows that the SFH of the observed field in IC 1613 is consistent with being constant over the entire lifetime of the galaxy. These observations rule out an early dominant episode of star formation in IC 1613. We compare the SFH of IC 1613 with expectations from cosmological models. Since most of the mass is in place at early times for low-mass halos, a naive expectation is that most of the star formation should have taken place at early times. Models in which star formation follows mass accretion result in too many stars formed early and gas mass fractions that are too low today (the 'over-cooling problem'). The depth of the present photometry of IC 1613 shows that, at a resolution of ?1 Gyr, the star formation rate is consistent with being constant, at even the earliest times, which is difficult to achieve in models where star formation follows mass assembly.

  12. Covered Product Category: Residential Gas Storage Water Heaters

    Office of Energy Efficiency and Renewable Energy (EERE)

    FEMP provides acquisition guidance across a variety of product categories, including gas storage water heaters, which are an ENERGY STAR-qualified product category. Federal laws and requirements mandate that agencies meet these efficiency requirements in all procurement and acquisition actions that are not specifically exempted by law.

  13. Intirion: ENERGY STAR Referral (MFRA-4GF) | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Intirion: ENERGY STAR Referral (MFRA-4GF) Intirion: ENERGY STAR Referral (MFRA-4GF) August 14, 2012 DOE referred the matter of Intirion refrigerator model MFRA-4GF to the U.S. Environmental Protection Agency, brand manager for the ENERGY STAR Program, for appropriate action after DOE testing showed that the model does not meet the ENERGY STAR specification. Intirion: ENERGY STAR Referral (MFRA-4GF) (89.26 KB) More Documents & Publications Samsung: ENERGY STAR Referral (RF26VAB) Friedrich:

  14. Kenmore: ENERGY STAR Referral (90701) | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    90701) Kenmore: ENERGY STAR Referral (90701) May 10, 2013 DOE referred the matter of Kenmore-brand dehumidifier, model number 90701, to the U.S. Environmental Protection Agency, brand manager for the ENERGY STAR Program, for appropriate action after DOE testing showed that the model does not meet the ENERGY STAR specification. Kenmore: ENERGY STAR Referral (90701) (174.75 KB) More Documents & Publications Kenmore: ENERGY STAR Referral (253.16582104) Haier: ENERGY STAR Referral (DE45EK)

  15. North Star Refrigerator: Order (2013-CE-5355)

    Broader source: Energy.gov [DOE]

    DOE ordered North Star Refrigerator Co., Inc. to pay a $8,000 civil penalty after finding North Star Refrigerator had failed to certify that any basic models of walk-in cooler and freezer components comply with the applicable energy conservation standards.

  16. ENERGY STAR Webinar: Portfolio Manager 101

    Broader source: Energy.gov [DOE]

    Hosted by the U.S. Environmental Protection Agency's (EPA's) ENERGY STAR, this webinar will introduce and demonstrate the EPA's ENERGY STAR Portfolio Manager tool. Attendees will learn how to navigate the new Portfolio Manager, add a property and enter details about it, enter energy and water consumption data, and more.

  17. A general hybrid radiation transport scheme for star formation simulations on an adaptive grid

    SciTech Connect (OSTI)

    Klassen, Mikhail; Pudritz, Ralph E.; Kuiper, Rolf; Peters, Thomas; Banerjee, Robi; Buntemeyer, Lars

    2014-12-10

    Radiation feedback plays a crucial role in the process of star formation. In order to simulate the thermodynamic evolution of disks, filaments, and the molecular gas surrounding clusters of young stars, we require an efficient and accurate method for solving the radiation transfer problem. We describe the implementation of a hybrid radiation transport scheme in the adaptive grid-based FLASH general magnetohydrodyanmics code. The hybrid scheme splits the radiative transport problem into a raytracing step and a diffusion step. The raytracer captures the first absorption event, as stars irradiate their environments, while the evolution of the diffuse component of the radiation field is handled by a flux-limited diffusion solver. We demonstrate the accuracy of our method through a variety of benchmark tests including the irradiation of a static disk, subcritical and supercritical radiative shocks, and thermal energy equilibration. We also demonstrate the capability of our method for casting shadows and calculating gas and dust temperatures in the presence of multiple stellar sources. Our method enables radiation-hydrodynamic studies of young stellar objects, protostellar disks, and clustered star formation in magnetized, filamentary environments.

  18. ENERGY STAR Appliance Verification Testing - Pilot Program Summary...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    ENERGY STAR Appliance Verification Testing - Pilot Program Summary Report dated February 3, 2012 ENERGY STAR Appliance Verification Testing - Pilot Program Summary Report dated ...

  19. FAQ's for: ENERGY STAR Verification Testing Pilot Program dated...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    FAQ's for: ENERGY STAR Verification Testing Pilot Program dated December 2010 FAQ's for: ENERGY STAR Verification Testing Pilot Program dated December 2010 This document is the ...

  20. China National BlueStar Group Corporation | Open Energy Information

    Open Energy Info (EERE)

    BlueStar Group Corporation Jump to: navigation, search Name: China National BlueStar Group Corporation Place: Beijing, Beijing Municipality, China Zip: 100029 Product: State-owned...

  1. Webinar: ENERGY STAR Hot Water Systems for High Performance Homes...

    Energy Savers [EERE]

    ENERGY STAR Hot Water Systems for High Performance Homes Webinar: ENERGY STAR Hot Water Systems for High Performance Homes This presentation is from the Building America research ...

  2. University of Minnesota (NorthernSTAR Building America Partnership...

    Open Energy Info (EERE)

    (NorthernSTAR Building America Partnership) Jump to: navigation, search Name: University of Minnesota (NorthernSTAR Building America Partnership) Place: St. Paul, MN Information...

  3. The Nuclear Spectroscopic Telescope Array (NuSTAR) Mission (Journal...

    Office of Scientific and Technical Information (OSTI)

    The Nuclear Spectroscopic Telescope Array (NuSTAR) Mission Citation Details In-Document Search Title: The Nuclear Spectroscopic Telescope Array (NuSTAR) Mission You are...

  4. The Nuclear Spectroscopic Telescope Array (NuSTAR) Mission (Journal...

    Office of Scientific and Technical Information (OSTI)

    The Nuclear Spectroscopic Telescope Array (NuSTAR) Mission Citation Details In-Document Search Title: The Nuclear Spectroscopic Telescope Array (NuSTAR) Mission Authors: Harrison,...

  5. The Nuclear Spectroscopic Telescope Array (NuSTAR) Mission (Journal...

    Office of Scientific and Technical Information (OSTI)

    Nuclear Spectroscopic Telescope Array (NuSTAR) Mission Citation Details In-Document Search Title: The Nuclear Spectroscopic Telescope Array (NuSTAR) Mission Authors: Harrison,...

  6. Prairie Star (07) Wind Farm | Open Energy Information

    Open Energy Info (EERE)

    Wind Farm Jump to: navigation, search Name Prairie Star (07) Wind Farm Facility Prairie Star (07) Sector Wind energy Facility Type Commercial Scale Wind Facility Status In...

  7. Silver Star Hot Springs Geothermal Area | Open Energy Information

    Open Energy Info (EERE)

    Silver Star Hot Springs Geothermal Area Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Silver Star Hot Springs Geothermal Area Contents 1 Area Overview 2 History and...

  8. Blue Star Energy Services (Pennsylvania) | Open Energy Information

    Open Energy Info (EERE)

    Star Energy Services (Pennsylvania) Jump to: navigation, search Name: Blue Star Energy Services Place: Pennsylvania Website: www.bluestarenergy.com Twitter: @keealliance Facebook:...

  9. Electrolux: ENERGY STAR Referral (EIDW6305***) | Department of...

    Broader source: Energy.gov (indexed) [DOE]

    the EPA for appropriate action after DOE testing showed that the model may not meet the ENERGY STAR specification. Electrolux: ENERGY STAR Referral (EIDW6305***) More Documents &...

  10. Sino Power Star Co Ltd SPSCAP | Open Energy Information

    Open Energy Info (EERE)

    Power Star Co Ltd SPSCAP Jump to: navigation, search Name: Sino Power Star Co Ltd (SPSCAP) Place: Beijing, Beijing Municipality, China Zip: 102628 Sector: Vehicles Product:...

  11. DOE Defends Decision to Revoke Energy Star Designation for Certain...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Decision to Revoke Energy Star Designation for Certain LG Refrigerators DOE Defends Decision to Revoke Energy Star Designation for Certain LG Refrigerators December 23, 2009 -...

  12. Eco Energy Cities Plc STAR group | Open Energy Information

    Open Energy Info (EERE)

    Energy Cities Plc STAR group Jump to: navigation, search Name: Eco Energy Cities Plc (STAR group) Place: Shanghai, Shanghai Municipality, China Sector: Carbon, Renewable Energy...

  13. ENERGY STAR Labeled Buildings and Plants | Open Energy Information

    Open Energy Info (EERE)

    STAR Labeled Buildings and Plants Jump to: navigation, search Name ENERGY STAR Labeled Buildings and Plants Data Format Excel Spreadsheet Geographic Scope United States TODO:...

  14. Prairie Star (08) Wind Farm | Open Energy Information

    Open Energy Info (EERE)

    Wind Farm Jump to: navigation, search Name Prairie Star (08) Wind Farm Facility Prairie Star (08) Sector Wind energy Facility Type Commercial Scale Wind Facility Status In...

  15. Home Performance with ENERGY STAR -- Webinar Slides | Department...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    with ENERGY STAR -- Webinar Slides Home Performance with ENERGY STAR -- Webinar Slides "Existing Homes Efficiency - If You Want BetterBuildings - Go with Home Performance with...

  16. North Star Electric Coop, Inc | Open Energy Information

    Open Energy Info (EERE)

    North Star Electric Coop, Inc Jump to: navigation, search Name: North Star Electric Coop, Inc Address: 441 State Hwy 172 NW Place: Baudette, MN Zip: 56623 Phone Number:...

  17. ENERGY STAR Certified Homes, Version 3 (Rev. 07) Inspection Checklists...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    ENERGY STAR Certified Homes, Version 3 (Rev. 07) Inspection Checklists for National Program Requirements ENERGY STAR Certified Homes, Version 3 (Rev. 07) Inspection Checklists for ...

  18. Home Performance with ENERGY STAR -- 10 Years of Continued Growth...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    ... to use the widely-recognized ENERGY STAR brand * Access to marketing toolkit on password protected ENERGY STAR website * Access to other resources such as standardized ...

  19. Energy Star Lighting Verification Program (Program for the Evaluation...

    Office of Scientific and Technical Information (OSTI)

    Technical Report: Energy Star Lighting Verification Program (Program for the Evaluation and Analysis of Residential Lighting) Citation Details In-Document Search Title: Energy Star ...

  20. Evaluation Prompts ENERGY STAR Program to Replace Web Tool, Saving...

    Broader source: Energy.gov (indexed) [DOE]

    U.S. Environmental Protection Agency's ENERGY STAR Residential Program, is part of the Case Study Series, highlighting how "Evaluation Prompts ENERGY STAR Program to Replace Web ...

  1. Generation of magnetic field on the accretion disk around a proto-first-star

    SciTech Connect (OSTI)

    Shiromoto, Yuki; Susa, Hajime; Hosokawa, Takashi

    2014-02-20

    The generation process of a magnetic field around a proto-first-star is studied. Utilizing the recent numerical results of proto-first-star formation based on radiation hydrodynamics simulations, we assess the magnetic field strength generated by the radiative force and the Biermann battery effect. We find that a magnetic field of ∼10{sup –9} G is generated on the surface of the accretion disk around the proto-first-star. The field strength on the accretion disk is smaller by two orders of magnitude than the critical value, above which the gravitational fragmentation of the disk is suppressed. Thus, the generated seed magnetic field hardly affect the dynamics of on-site first star formation directly, unless an efficient amplification process is taken into consideration. We also find that the generated magnetic field is continuously blown out from the disk on the outflows to the poles, that are driven by the thermal pressure of photoheated gas. The strength of the diffused magnetic field in low-density regions is ∼10{sup –14}-10{sup –13} G at n {sub H} = 10{sup 3} cm{sup –3}, which could play an important role in the next generation star formation, as well as the seeds of the magnetic field in the present-day universe.

  2. Gas sensor

    DOE Patents [OSTI]

    Schmid, Andreas K.; Mascaraque, Arantzazu; Santos, Benito; de la Figuera, Juan

    2014-09-09

    A gas sensor is described which incorporates a sensor stack comprising a first film layer of a ferromagnetic material, a spacer layer, and a second film layer of the ferromagnetic material. The first film layer is fabricated so that it exhibits a dependence of its magnetic anisotropy direction on the presence of a gas, That is, the orientation of the easy axis of magnetization will flip from out-of-plane to in-plane when the gas to be detected is present in sufficient concentration. By monitoring the change in resistance of the sensor stack when the orientation of the first layer's magnetization changes, and correlating that change with temperature one can determine both the identity and relative concentration of the detected gas. In one embodiment the stack sensor comprises a top ferromagnetic layer two mono layers thick of cobalt deposited upon a spacer layer of ruthenium, which in turn has a second layer of cobalt disposed on its other side, this second cobalt layer in contact with a programmable heater chip.

  3. DOE Science Showcase - Startup Stars | OSTI, US Dept of Energy Office of

    Office of Scientific and Technical Information (OSTI)

    Scientific and Technical Information Startup Stars The Next Top Energy Innovator Iowa Powder Atomization Technologies, Inc. (IPAT) using gas atomization technology developed by AMES Laboratory Umpqua Energy using gasoline technology developed by ANL Vorbeck Materials using lithium-ion battery technology developed by PNNL The America's Next Top Energy Innovator Challenge, a part of the Startup America initiative, made it easier for start-ups to use inventions and technology developed at the

  4. SUPERMASSIVE DARK STARS: DETECTABLE IN JWST

    SciTech Connect (OSTI)

    Freese, Katherine; Ilie, Cosmin; Spolyar, Douglas; Valluri, Monica; Bodenheimer, Peter

    2010-06-20

    The first phase of stellar evolution in the history of the universe may be dark stars (DSs), powered by dark matter (DM) heating rather than by nuclear fusion. Weakly interacting massive particles (WIMPs), which may be their own antipartners, collect inside the first stars and annihilate to produce a heat source that can power the stars for millions to billions of years. In this paper, we show that these objects can grow to be supermassive dark stars (SMDSs) with masses {approx_gt}(10{sup 5}-10{sup 7}) M{sub sun}. The growth continues as long as DM heating persists, since DSs are large and cool (surface temperature {approx_lt}5 x 10{sup 4} K) and do not emit enough ionizing photons to prevent further accretion of baryons onto the star. The DM may be provided by two mechanisms: (1) gravitational attraction of DM particles on a variety of orbits not previously considered and (2) capture of WIMPs due to elastic scattering. Once the DM fuel is exhausted, the SMDS becomes a heavy main-sequence star; these stars eventually collapse to form massive black holes (BHs) that may provide seeds for supermassive BHs in the universe. SMDSs are very bright, with luminosities exceeding (10{sup 9}-10{sup 11}) L{sub sun}. We demonstrate that for several reasonable parameters, these objects will be detectable with the James Webb Space Telescope. Such an observational discovery would confirm the existence of a new phase of stellar evolution powered by DM.

  5. Wave-Based Subsurface Guide Star

    SciTech Connect (OSTI)

    Lehman, S K

    2011-07-26

    Astronomical or optical guide stars are either natural or artificial point sources located above the Earth's atmosphere. When imaged from ground-based telescopes, they are distorted by atmospheric effects. Knowing the guide star is a point source, the atmospheric distortions may be estimated and, deconvolved or mitigated in subsequent imagery. Extending the guide star concept to wave-based measurement systems to include acoustic, seismo-acoustic, ultrasonic, and radar, a strong artificial scatterer (either acoustic or electromagnetic) may be buried or inserted, or a pre-existing or natural sub-surface point scatterer may be identified, imaged, and used as a guide star to determine properties of the sub-surface volume. That is, a data collection is performed on the guide star and the sub-surface environment reconstructed or imaged using an optimizer assuming the guide star is a point scatterer. The optimization parameters are the transceiver height and bulk sub-surface background refractive index. Once identified, the refractive index may be used in subsequent reconstructions of sub-surface measurements. The wave-base guide star description presented in this document is for a multimonostatic ground penetrating radar (GPR) but is applicable to acoustic, seismo-acoustic, and ultrasonic measurement systems operating in multimonostatic, multistatic, multibistatic, etc., modes.

  6. Natural Gas Weekly Update

    Annual Energy Outlook [U.S. Energy Information Administration (EIA)]

    natural gas demand, thereby contributing to larger net injections of natural gas into storage. Other Market Trends: EIA Releases The Natural Gas Annual 2006: The Energy...

  7. Natural Gas Applications

    Annual Energy Outlook [U.S. Energy Information Administration (EIA)]

    Gas Applications. If you need assistance viewing this page, please call (202) 586-8800. Energy Information Administration Home Page Home > Natural Gas > Natural Gas Applications...

  8. A SUPER-EARTH TRANSITING A NAKED-EYE STAR

    SciTech Connect (OSTI)

    Winn, Joshua N.; Matthews, Jaymie M.; Kallinger, Thomas; Dragomir, Diana; Dawson, Rebekah I.; Holman, Matthew J.; Sasselov, Dimitar; Fabrycky, Daniel; Guenther, David B.; Moffat, Anthony F. J.; Rowe, Jason F.; Rucinski, Slavek

    2011-08-10

    We have detected transits of the innermost planet 'e' orbiting 55 Cnc (V = 6.0), based on two weeks of nearly continuous photometric monitoring with the MOST space telescope. The transits occur with the period (0.74 days) and phase that had been predicted by Dawson and Fabrycky, and with the expected duration and depth for the crossing of a Sun-like star by a hot super-Earth. Assuming the star's mass and radius to be 0.963{sup +0.051}{sub -0.029} M{sub sun} and 0.943 {+-} 0.010 R{sub sun}, the planet's mass, radius, and mean density are 8.63 {+-} 0.35 M{sub +}, 2.00 {+-} 0.14 R{sub +}, and 5.9{sup +1.5}{sub -1.1} g cm{sup -3}, respectively. The mean density is comparable to that of Earth, despite the greater mass and consequently greater compression of the interior of 55 Cnc e. This suggests a rock-iron composition supplemented by a significant mass of water, gas, or other light elements. Outside of transits, we detected a sinusoidal signal resembling the expected signal due to the changing illuminated phase of the planet, but with a full range (168 {+-} 70 ppm) too large to be reflected light or thermal emission. This signal has no straightforward interpretation and should be checked with further observations. The host star of 55 Cnc e is brighter than that of any other known transiting planet, which will facilitate future investigations.

  9. GAS SEAL

    DOE Patents [OSTI]

    Monson, H.; Hutter, E.

    1961-07-11

    A seal is described for a cover closing an opening in the top of a pressure vessel that may house a nuclear reactor. The seal comprises a U-shaped trough formed on the pressure vessel around the opening therein, a mass of metal in the trough, and an edge flange on the cover extending loosely into the trough and dipping into the metal mass. The lower portion of the metal mass is kept melted, and the upper portion, solid. The solid pontion of the metal mass prevents pressure surges in the vessel from expelling the liquid portion of the metal mass from the trough; the liquld portion, thus held in place by the solid portion, does not allow gas to go through, and so gas cannot escape through shrinkage holes in the solid portion.

  10. New Mexico Natural Gas in Underground Storage (Base Gas) (Million...

    Annual Energy Outlook [U.S. Energy Information Administration (EIA)]

    Base Gas) (Million Cubic Feet) New Mexico Natural Gas in Underground Storage (Base Gas) ... Underground Base Natural Gas in Storage - All Operators New Mexico Underground Natural Gas ...