National Library of Energy BETA

Sample records for halogen bulbs halo

  1. Jacketed lamp bulb envelope

    DOE Patents [OSTI]

    MacLennan, Donald A. (Gaithersburg, MD); Turner, Brian P. (Damascus, MD); Gitsevich, Aleksandr (Gaithersburg, MD); Bass, Gary K. (Mt. Airy, MD); Dolan, James T. (Frederick, MD); Kipling, Kent (Gaithersburg, MD); Kirkpatrick, Douglas A. (Great Falls, VA); Leng, Yongzhang (Damascus, MD); Levin, Izrail (Silver Spring, MD); Roy, Robert J. (Frederick, MD); Shanks, Bruce (Gaithersburg, MD); Smith, Malcolm (Alexandria, VA); Trimble, William C. (Columbia, MD); Tsai, Peter (Olney, MD)

    2001-01-01

    A jacketed lamp bulb envelope includes a ceramic cup having an open end and a partially closed end, the partially closed end defining an aperture, a lamp bulb positioned inside the ceramic cup abutting the aperture, and a reflective ceramic material at least partially covering a portion of the bulb not abutting the aperture. The reflective ceramic material may substantially fill an interior volume of the ceramic cup not occupied by the bulb. The ceramic cup may include a structural feature for aiding in alignment of the jacketed lamp bulb envelope in a lamp. The ceramic cup may include an external flange about a periphery thereof. One example of a jacketed lamp bulb envelope includes a ceramic cup having an open end and a closed end, a ceramic washer covering the open end of the ceramic cup, the washer defining an aperture therethrough, a lamp bulb positioned inside the ceramic cup abutting the aperture, and a reflective ceramic material filling an interior volume of the ceramic cup not occupied by the bulb. A method of packing a jacketed lamp bulb envelope of the type comprising a ceramic cup with a lamp bulb disposed therein includes the steps of filling the ceramic cup with a flowable slurry of reflective material, and applying centrifugal force to the cup to pack the reflective material therein.

  2. Lamp bulb with integral reflector

    DOE Patents [OSTI]

    Levin, Izrail (Silver Spring, MD); Shanks, Bruce (Gaithersburg, MD); Sumner, Thomas L. (Wheaton, MD)

    2001-01-01

    An improved electrodeless discharge lamp bulb includes an integral ceramic reflector as a portion of the bulb envelope. The bulb envelope further includes two pieces, a reflector portion or segment is cast quartz ceramic and a light transmissive portion is a clear fused silica. In one embodiment, the cast quartz ceramic segment includes heat sink fins or stubs providing an increased outside surface area to dissipate internal heat. In another embodiment, the quartz ceramic segment includes an outside surface fused to eliminate gas permeation by polishing.

  3. Halogenated solvent remediation

    DOE Patents [OSTI]

    Sorenson, Jr., Kent S. (Windsor, CO)

    2008-11-11

    Methods for enhancing bioremediation of ground water contaminated with nonaqueous halogenated solvents are disclosed. An illustrative method includes adding an electron donor for microbe-mediated anaerobic reductive dehalogenation of the halogenated solvents, which electron donor enhances mass transfer of the halogenated solvents from residual source areas into the aqueous phase of the ground water. Illustrative electron donors include C.sub.2-C.sub.4 carboxylic acids and hydroxy acids, salts thereof, esters of C.sub.2-C.sub.4 carboxylic acids and hydroxy acids, and mixtures thereof, of which lactic acid, salts of lactic acid--such as sodium lactate, lactate esters, and mixtures thereof are particularly illustrative. The microbes are either indigenous to the ground water, or such microbes can be added to the ground water in addition to the electron donor.

  4. Halogenated solvent remediation

    DOE Patents [OSTI]

    Sorenson, Kent S.

    2004-08-31

    Methods for enhancing bioremediation of ground water contaminated with nonaqueous halogenated solvents are disclosed. A preferred method includes adding a composition to the ground water wherein the composition is an electron donor for microbe-mediated reductive dehalogenation of the halogenated solvents and enhances mass transfer of the halogenated solvents from residual source areas into the aqueous phase of the ground water. Illustrative compositions effective in these methods include surfactants such as C.sub.2 -C.sub.4 carboxylic acids and hydroxy acids, salts thereof, esters of C.sub.2 -C.sub.4 carboxylic acids and hydroxy acids, and mixtures thereof. Especially preferred compositions for use in these methods include lactic acid, salts of lactic acid, such as sodium lactate, lactate esters, and mixtures thereof. The microbes are either indigenous to the ground water, or such microbes can be added to the ground water in addition to the composition.

  5. MULTIPHOTON DISSOCIATION PRODUCTS FROM HALOGENATED HYDROCARBONS

    E-Print Network [OSTI]

    Sudbo, Aa. S.

    2011-01-01

    FROM HALOGENATED HYDROCARBONS RECE1VED Aa. S. Sudbo, P. A.FROM HALOGENATED HYDROCARBONS LBL-6966 Aa. S. Sudbo, t P. A.

  6. How Energy-Efficient Light Bulbs Compare with Traditional Incandescent...

    Office of Environmental Management (EM)

    Energy-Efficient Light Bulbs Compare with Traditional Incandescents How Energy-Efficient Light Bulbs Compare with Traditional Incandescents November 5, 2014 - 11:39pm Addthis By...

  7. Consumer Light Bulb Changes: Briefing and Resources for Media...

    Office of Environmental Management (EM)

    background information on the new legislation and the types of energy-efficient lighting available today. Consumer Light Bulb Changes: Briefing and Resources for Media and...

  8. How Energy-Efficient Light Bulbs Compare with Traditional Incandescent...

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

    used light fixtures or bulbs with models that have earned the ENERGY STAR, you can save 75 each year. Compared to traditional incandescents, energy-efficient lightbulbs...

  9. SuperBulbs Inc | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIX ECoop Inc JumpHeter BatterySolarfinMarketMember CorpSunvie SAS Jump to:SunwaysSuperBulbs

  10. How Energy-Efficient Light Bulbs Compare with Traditional Incandescent...

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

    you can save 75 each year. Compared to traditional incandescents, energy-efficient lightbulbs such as halogen incandescents, compact fluorescent lamps (CFLs), and light emitting...

  11. Photodissociation Dynamics of Halogen Oxide Species 

    E-Print Network [OSTI]

    Dooley, Kristin S.

    2010-07-14

    The focus of this dissertation is the study of the photodissociation dynamics of halogen oxide species (XO, X = Cl, Br, I). These radical species are known to be important in stratospheric and tropospheric ozone depletion ...

  12. Energy efficient alternatives to halogen torchieres

    SciTech Connect (OSTI)

    Siminovitch, M.; Marr, L.; Mitchell, J.; Page, E.

    1997-03-01

    A series of novel energy efficient torchiere systems have been developed using compact fluorescent lamps (CFLs). These systems were studied photometrically and compared with the performance of traditional commercially available tungsten halogen sources. Gonio-photometric data and power assessments indicate that significant lighting energy savings can be obtained by utilizing CFL sources instead of standard tungsten halogen sources. This energy savings is jointly due to the higher source efficacy of the CFLs and the surprisingly poor performance of the imported 300 Watt halogen lamps. Experimental data shows that a 50 to 60 Watt CFL will effectively lumen match a variety of 300 Watt tungsten halogen sources with 5 to 10 times the efficacy. CFL torchieres have additional benefits of higher power quality and cooler lamp operating temperature, making them safer fixtures.

  13. Crystallographic studies on enzymatic halogenation of natural products

    E-Print Network [OSTI]

    Blasiak, Leah Cameron

    2008-01-01

    Halogenated natural products are common and serve roles as hormones, pesticides, antibiotics, and anti-tumor agents. The incorporation of a halogen atom into an organic scaffold can tune the molecule's potency and selectivity, ...

  14. Method and apparatus for low temperature destruction of halogenated hydrocarbons

    DOE Patents [OSTI]

    Reagen, William Kevin (Stillwater, MN); Janikowski, Stuart Kevin (Idaho Falls, ID)

    1999-01-01

    A method and apparatus for decomposing halogenated hydrocarbons are provided. The halogenated hydrocarbon is mixed with solvating agents and maintained in a predetermined atmosphere and at a predetermined temperature. The mixture is contacted with recyclable reactive material for chemically reacting with the recyclable material to create dehalogenated hydrocarbons and halogenated inorganic compounds. A feature of the invention is that the process enables low temperature destruction of halogenated hydrocarbons.

  15. Zevenhoven & Kilpinen Halogens, dioxins/furans 17.6.2001 7-1 Chapter 7 Halogens,

    E-Print Network [OSTI]

    Laughlin, Robert B.

    Zevenhoven & Kilpinen Halogens, dioxins/furans 17.6.2001 7-1 Chapter 7 Halogens, dioxins/furans 7 in Figure 7.1. The polychlorinated dibenzo -(p) dioxins and -furans (PCDD/Fs) that are found in PCBs and may, dioxins/furans 17.6.2001 7-2 2,3,7,8 tetrachloro dibenzo - p- dioxin PCB furan 2,3,7,8 tetrachlorodibenzo

  16. Process for removal of hydrogen halides or halogens from incinerator gas

    DOE Patents [OSTI]

    Huang, H.S.; Sather, N.F.

    1987-08-21

    A process for reducing the amount of halogens and halogen acids in high temperature combustion gas and through their removal, the formation of halogenated organics at lower temperatures, with the reduction being carried out electrochemically by contacting the combustion gas with the negative electrode of an electrochemical cell and with the halogen and/or halogen acid being recovered at the positive electrode.

  17. Text-Alternative Version: L Prize™: The Race for Super Efficient Light Bulbs

    Broader source: Energy.gov [DOE]

    Below is the text-alternative version of the L Prize™: The Race for Super Efficient Light Bulbs webcast.

  18. Tokamak halo currents

    SciTech Connect (OSTI)

    Boozer, Allen H. [Department of Applied Physics and Applied Mathematics Columbia University, New York, New York 10027 (United States)] [Department of Applied Physics and Applied Mathematics Columbia University, New York, New York 10027 (United States)

    2013-08-15

    A halo current flows for part of its path through the plasma edge and for part through the chamber walls and can be as large as tenths of the plasma current. The primary interest in halo currents is the large force that they can exert on machine components. Two discordant constraints are central to the theory: (1) Halo currents must produce the magnetic field distribution required to maintain plasma force balance—a distribution that depends on the two angular coordinates of a torus. (2) Halo currents must flow along the magnetic field lines in the plasma, which implies a dependence on a linear combination of the two angular coordinates—only one angular coordinate is free. The physics basis of these two constraints is explained as is their application to the calculation of the properties of halo currents, such as their broad toroidal spectrum. Existing codes could be used to (1) provide detailed comparisons with experiments to validate that the critical elements of physics are adequately included, (2) allow more complete predictions for future machines such as ITER, and (3) design shunts and resistive elements to ensure halo currents follow paths that are the least damaging to the machine. The physics of halo currents implies that it may be possible to feedback stabilize resistive wall modes beyond the ideal-wall limit.

  19. Free Energy Efficiency Kit includes CFL light bulbs,

    E-Print Network [OSTI]

    Rose, Annkatrin

    Free Energy Efficiency Kit Kit includes CFL light bulbs, spray foam, low-flow shower head, and more for discounted energy assessments. FREE HOME ENERGY EFFICIENCY SEMINAR N e w R i ver L i g ht & Pow e r a n d W! Building Science 101 Presentation BPI Certified Building Professionals will present home energy efficiency

  20. DOE Requires Westinghouse to Cease Sales of Two Light Bulb Models...

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

    action against Westinghouse Lighting Corporation, the company must cease sales of two light bulb models - medium based CFL basic model 15GLOBE652 (Westinghouse product code...

  1. Photochemical reductive elimination of halogen from transition metal complexes

    E-Print Network [OSTI]

    Cook, Timothy R. (Timothy Raymond), 1982-

    2010-01-01

    This thesis is focused on the synthesis and study of transition metal complexes that undergo halogen elimination when irradiated with UV and visible light. This chemistry is relevant for solar energy storage schemes in ...

  2. Enhanced metabolism of halogenated hydrocarbons in transgenic plants containing mammalian

    E-Print Network [OSTI]

    Doty, Sharon Lafferty

    Enhanced metabolism of halogenated hydrocarbons in transgenic plants containing mammalian efficient remediation of many sites contaminated with haloge- nated hydrocarbons. Trichloroethylene (TCE hydrocarbon, ethylene dibromide (EDB; dibromoeth- ane), was used as a soil fumigant to kill nematodes

  3. Halogenated naphthyl methoxy piperidines for mapping serotonin transporter sites

    DOE Patents [OSTI]

    Goodman, M.M.; Faraj, B.

    1999-07-06

    Halogenated naphthyl methoxy piperidines having a strong affinity for the serotonin transporter are disclosed. Those compounds can be labeled with positron-emitting and/or gamma emitting halogen isotopes by a late step synthesis that maximizes the useable lifeterm of the label. The labeled compounds are useful for localizing serotonin transporter sites by positron emission tomography and/or single photon emission computed tomography.

  4. Treatment of halogen-containing waste and other waste materials

    DOE Patents [OSTI]

    Forsberg, Charles W. (Oak Ridge, TN); Beahm, Edward C. (Oak Ridge, TN); Parker, George W. (Concord, TN)

    1997-01-01

    A process for treating a halogen-containing waste material. The process provides a bath of molten glass containing a sacrificial metal oxide capable of reacting with a halogen in the waste material. The sacrificial metal oxide is present in the molten glass in at least a stoichiometric amount with respect to the halogen in the waste material. The waste material is introduced into the bath of molten glass to cause a reaction between the halogen in the waste material and the sacrificial metal oxide to yield a metal halide. The metal halide is a gas at the temperature of the molten glass. The gaseous metal halide is separated from the molten glass and contacted with an aqueous scrubber solution of an alkali metal hydroxide to yield a metal hydroxide or metal oxide-containing precipitate and a soluble alkali metal halide. The precipitate is then separated from the aqueous scrubber solution. The molten glass containing the treated waste material is removed from the bath as a waste glass. The process of the invention can be used to treat all types of waste material including radioactive wastes. The process is particularly suited for separating halogens from halogen-containing wastes.

  5. Treatment of halogen-containing waste and other waste materials

    DOE Patents [OSTI]

    Forsberg, C.W.; Beahm, E.C.; Parker, G.W.

    1997-03-18

    A process is described for treating a halogen-containing waste material. The process provides a bath of molten glass containing a sacrificial metal oxide capable of reacting with a halogen in the waste material. The sacrificial metal oxide is present in the molten glass in at least a stoichiometric amount with respect to the halogen in the waste material. The waste material is introduced into the bath of molten glass to cause a reaction between the halogen in the waste material and the sacrificial metal oxide to yield a metal halide. The metal halide is a gas at the temperature of the molten glass. The gaseous metal halide is separated from the molten glass and contacted with an aqueous scrubber solution of an alkali metal hydroxide to yield a metal hydroxide or metal oxide-containing precipitate and a soluble alkali metal halide. The precipitate is then separated from the aqueous scrubber solution. The molten glass containing the treated waste material is removed from the bath as a waste glass. The process of the invention can be used to treat all types of waste material including radioactive wastes. The process is particularly suited for separating halogens from halogen-containing wastes. 3 figs.

  6. Metal halogen battery system with multiple outlet nozzle for hydrate

    DOE Patents [OSTI]

    Bjorkman, Jr., Harry K. (Birmingham, MI)

    1983-06-21

    A metal halogen battery system, including at least one cell having a positive electrode and a negative electrode contacted by aqueous electrolyte containing the material of said metal and halogen, store means whereby halogen hydrate is formed and stored as part of an aqueous material, means for circulating electrolyte through the cell and to the store means, and conduit means for transmitting halogen gas formed in the cell to a hydrate former whereby the hydrate is formed in association with the store means, said store means being constructed in the form of a container which includes a filter means, said filter means being inoperative to separate the hydrate formed from the electrolyte, said system having, a hydrate former pump means associated with the store means and being operative to intermix halogen gas with aqueous electrolyte to form halogen hydrate, said hydrate former means including, multiple outlet nozzle means connected with the outlet side of said pump means and being operative to minimize plugging, said nozzle means being comprised of at least one divider means which is generally perpendicular to the rotational axes of gears within the pump means, said divider means acting to divide the flow from the pump means into multiple outlet flow paths.

  7. Tired of changing light bulbs AND want to save money? Still using 100 year-old technology?

    E-Print Network [OSTI]

    Gustafsson, Torgny

    Tired of changing light bulbs AND want to save money? Still using 100 year-old technology? TAKE THE COMPACT FLUORESCENT LIGHT BULB CHALLENGE! · A 23 W Compact bulb gives the same light as a 100W regular?) ·Fine print: You will also reduce Global Warming pollution. Over its lifetime, a "100W" Compact

  8. The first halos

    E-Print Network [OSTI]

    Dominik J. Schwarz

    2006-12-15

    The size and time of formation of the first gravitationally bound objects in the Universe is set by the microphysical properties of the dark matter. It is argued that observations seem to favour cold and thermal candidates for the main contribution to the dark matter. For that type of dark matter, the size and time of formation of the first halos is determined by the elastic cross sections and mass of the CDM particles. Consequently, the astrophysics of CDM might allow us to measure some of the fundamental parameters of CDM particles. Essential for observations is the survival rate and spatial distribution of the very first objetcs, which are currently under debate.

  9. Halogenated 1'-methyl-1,2'-bipyrroles (MBPs) in the Norwestern Atlantic

    E-Print Network [OSTI]

    Pangallo, Kristin C

    2009-01-01

    Halogenated 1'-methyl-1,2'-bipyrroles (MBPs) are a distinctive class of marine organic compounds. They are naturally produced, they have a unique carbon structure, they are highly halogenated, and they bioaccumulate in ...

  10. CALiPER Benchmark Report: Performance of Halogen Incandescent MR16 Lamps and LED Replacement

    SciTech Connect (OSTI)

    None

    2008-11-01

    This benchmark report addresses the halogen MR16 lamp and its commercially available light-emitting diode (LED) replacements.

  11. Symmetric and asymmetric halogen-containing metallocarboranylporphyrins and uses thereof

    DOE Patents [OSTI]

    Miura, Michiko; Wu, Haitao

    2013-05-21

    The present invention is directed to low toxicity boronated compounds and methods for their use in the treatment, visualization, and diagnosis of tumors. More specifically, the present invention is directed to low toxicity halogenated, carborane-containing 5,10,15,20-tetraphenylporphyrin compounds and methods for their use particularly in boron neutron capture therapy (BNCT) and photodynamic therapy (PDT) for the treatment of tumors of the brain, head and neck, and surrounding tissue. The invention is also directed to using these halogenated, carborane-containing tetraphenylporphyrin compounds in methods of tumor imaging and/or diagnosis such as MRI, SPECT, or PET.

  12. Halo modelling in chameleon theories

    SciTech Connect (OSTI)

    Lombriser, Lucas; Koyama, Kazuya [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Burnaby Road, Portsmouth, PO1 3FX (United Kingdom); Li, Baojiu, E-mail: lucas.lombriser@port.ac.uk, E-mail: kazuya.koyama@port.ac.uk, E-mail: baojiu.li@durham.ac.uk [Institute for Computational Cosmology, Ogden Centre for Fundamental Physics, Department of Physics, University of Durham, Science Laboratories, South Road, Durham, DH1 3LE (United Kingdom)

    2014-03-01

    We analyse modelling techniques for the large-scale structure formed in scalar-tensor theories of constant Brans-Dicke parameter which match the concordance model background expansion history and produce a chameleon suppression of the gravitational modification in high-density regions. Thereby, we use a mass and environment dependent chameleon spherical collapse model, the Sheth-Tormen halo mass function and linear halo bias, the Navarro-Frenk-White halo density profile, and the halo model. Furthermore, using the spherical collapse model, we extrapolate a chameleon mass-concentration scaling relation from a ?CDM prescription calibrated to N-body simulations. We also provide constraints on the model parameters to ensure viability on local scales. We test our description of the halo mass function and nonlinear matter power spectrum against the respective observables extracted from large-volume and high-resolution N-body simulations in the limiting case of f(R) gravity, corresponding to a vanishing Brans-Dicke parameter. We find good agreement between the two; the halo model provides a good qualitative description of the shape of the relative enhancement of the f(R) matter power spectrum with respect to ?CDM caused by the extra attractive gravitational force but fails to recover the correct amplitude. Introducing an effective linear power spectrum in the computation of the two-halo term to account for an underestimation of the chameleon suppression at intermediate scales in our approach, we accurately reproduce the measurements from the N-body simulations.

  13. M362K First Midterm Exam. February 7, 2002 Problem 1. Light Bulbs

    E-Print Network [OSTI]

    Voloch, Felipe

    M362K First Midterm Exam. February 7, 2002 Problem 1. Light Bulbs Suppose the probability function hiking, and a 20% chance that I'll stay home and play soccer. The (conditional) probability of my getting

  14. A critical period for activity-dependent synaptic development during olfactory bulb adult neurogenesis

    E-Print Network [OSTI]

    Kelsch, Wolfgang

    New neurons integrate in large numbers into the mature olfactory bulb circuit throughout life. The factors controlling the synaptic development of adult-born neurons and their connectivity remain essentially unknown. We ...

  15. Method for selective dehalogenation of halogenated polyaromatic compounds

    DOE Patents [OSTI]

    Farcasiu, Malvina (Pittsburgh, PA); Petrosius, Steven C. (Library, PA)

    1994-01-01

    A method for dehalogenating halogenated polyaromatic compounds is provided wherein the polyaromatic compounds are mixed with a hydrogen donor solvent and a carbon catalyst in predetermined proportions, the mixture is maintained at a predetermined pressure, and the mixture is heated to a predetermined temperature and for a predetermined time.

  16. Alkali and Halogen Chemistry in Volcanic Gases on Io

    E-Print Network [OSTI]

    Laura Schaefer; Bruce Fegley Jr

    2004-09-20

    We use chemical equilibrium calculations to model the speciation of alkalis and halogens in volcanic gases emitted on Io. The calculations cover wide temperature (500-2000 K) and pressure (10^-6 to 10^+1 bars) ranges, which overlap the nominal conditions at Pele (T = 1760 K, P = 0.01 bars). About 230 compounds of 11 elements (O, S, Li, Na, K, Rb, Cs, F, Cl, Br, I) are considered. We predict the major alkali and halogen species in a Pele-like volcanic gas and the major alklai and halogen condensates. We also model disequilibrium chemistry of the alkalis and halogens in the volcanic plume. Based on this work and our prior modeling for Na, K, and Cl in a volcanic plume, we predict the major loss processes for the alkali halide gases are photolysis and/or condensation onto grains. On the basis of elemental abundances and photochemical lifetimes, we recommend searching for gaseous KCl, NaF, LiF, LiCl, RbF, RbCl, CsF, and CsCl around volcanic vents during eruptions. Based on abundance considerations and observations of brown dwarfs, we also recommend a search of Io's extended atmosphere and the Io plasma torus for neutral and ionized Li, Cs, Rb, and F.

  17. Halo model and halo properties in Galileon gravity cosmologies

    SciTech Connect (OSTI)

    Barreira, Alexandre; Li, Baojiu; Hellwing, Wojciech A.; Baugh, Carlton M.; Lombriser, Lucas; Pascoli, Silvia E-mail: baojiu.li@durham.ac.uk E-mail: llo@roe.ac.uk E-mail: silvia.pascoli@durham.ac.uk

    2014-04-01

    We investigate the performance of semi-analytical modelling of large-scale structure in Galileon gravity cosmologies using results from N-body simulations. We focus on the Cubic and Quartic Galileon models that provide a reasonable fit to CMB, SNIa and BAO data. We demonstrate that the Sheth-Tormen mass function and linear halo bias can be calibrated to provide a very good fit to our simulation results. We also find that the halo concentration-mass relation is well fitted by a power law. The nonlinear matter power spectrum computed in the halo model approach is found to be inaccurate in the mildly nonlinear regime, but captures reasonably well the effects of the Vainshtein screening mechanism on small scales. In the Cubic model, the screening mechanism hides essentially all of the effects of the fifth force inside haloes. In the case of the Quartic model, the screening mechanism leaves behind residual modifications to gravity, which make the effective gravitational strength time-varying and smaller than the standard value. Compared to normal gravity, this causes a deficiency of massive haloes and leads to a weaker matter clustering on small scales. For both models, we show that there are realistic halo occupation distributions of Luminous Red Galaxies that can match both the observed large-scale clustering amplitude and the number density of these galaxies.

  18. Chem 115Lithium-Halogen ExchangeMyers RLi + R'X RX + R'Li

    E-Print Network [OSTI]

    Chem 115Lithium-Halogen ExchangeMyers RLi + R'X RX + R'Li Lithium-halogen exchange reactions are essentially inert. 2 t-BuLi t-BuI + RLi t-BuLi isobutene + isobutane + LiI Lithium-halogen exchange reactions, and lithium iodide. H OEtBr H H OEtLi H1.1 eq n-BuLi Et2O, !80 °C Lau, K. S.; Schlosser, M. J. Org. Chem. 1978

  19. Analysis and Characterization of Halogenated Transformation Products of Pharmaceuticals and Personal Care Products in Wastewater Effluent

    E-Print Network [OSTI]

    Bulloch, Daryl Neil

    2013-01-01

    for Halogenated Analogs of Bisphenol A. Environ. Healthof aqueous chlorination of bisphenol A and their estrogenicJ. L. ; Olea, N. , Bisphenol-A and chlorinated derivatives

  20. Nuclear Halo and Molecular States

    E-Print Network [OSTI]

    N. A. Orr

    2000-11-02

    Significant advances have been made in recent years in the exploration of clustering in light nuclei. This progress has arisen not only from the investigation of new systems, but also through the development and application of novel probes. This paper will briefly review selected topics concerning halo and molecular states in light nuclei through examples provided by the neutron-rich Be isotopes.

  1. Zinc halogen battery electrolyte composition with lead additive

    DOE Patents [OSTI]

    Henriksen, Gary L. (Troy, MI)

    1981-01-01

    This disclosure relates to a zinc halogen battery electrolyte composition containing an additive providing improved zinc-on-zinc recyclability. The improved electrolyte composition involves the use of a lead additive to inhibit undesirable irregular plating and reduce nodular or dendritic growth on the electrode surface. The lead-containing electrolyte composition of the present invention appears to influence not only the morphology of the base plate zinc, but also the morphology of the zinc-on-zinc replate. In addition, such lead-containing electrolyte compositions appear to reduce hydrogen formation.

  2. Halogen eAppraisal - Performance Appraisals | The Ames Laboratory

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformation Current HABFESOpportunitiesNERSCGrid-based29Hai Ah Nam Hai Ah Nam-TheHalogen

  3. Uncovering CDM halo substructure with tidal streams

    E-Print Network [OSTI]

    R. A. Ibata; G. F. Lewis; M. J. Irwin

    2001-10-31

    Models for the formation and growth of structure in a cold dark matter dominated universe predict that galaxy halos should contain significant substructure. Studies of the Milky Way, however, have yet to identify the expected few hundred sub-halos with masses greater than about 10^6 Msun. Here we propose a test for the presence of sub-halos in the halos of galaxies. We show that the structure of the tidal tails of ancient globular clusters is very sensitive to heating by repeated close encounters with the massive dark sub-halos. We discuss the detection of such an effect in the context of the next generation of astrometric missions, and conclude that it should be easily detectable with the GAIA dataset. The finding of a single extended cold stellar stream from a globular cluster would support alternative theories, such as self-interacting dark matter, that give rise to smoother halos.

  4. Dark galactic halos without dark matter

    E-Print Network [OSTI]

    R. K. Nesbet

    2015-03-03

    Using standard Einstein theory, baryonic mass cannot account for observed galactic rotation velocities and gravitational lensing, attributed to galactic dark matter halos. In contrast, theory constrained by Weyl conformal scaling symmetry explains observed galactic rotation in the halo region without invoking dark matter. An explanation of dark halos, gravitational lensing, and structural stabilization, without dark matter and consistent with conformal theory, is proposed here. Condensation of uniform primordial matter into a material cloud or galaxy vacates a large surrounding spherical halo. Within such an extended vacancy in the original cosmic background mass-energy density, conformal theory predicts centripetal acceleration of the observed magnitude.

  5. Evidence of a halo formation mechanism in the Spallation Neutron...

    Office of Scientific and Technical Information (OSTI)

    Published Article: Evidence of a halo formation mechanism in the Spallation Neutron Source linac Title: Evidence of a halo formation mechanism in the Spallation Neutron Source...

  6. Pairing Correlations in halo Nuclei

    E-Print Network [OSTI]

    H. Sagawa; K. Hagino

    2007-09-10

    Paring correlations in weakly bound halo nuclei $^{6}$He and $^{11}$Li are studied by using a three-body model with a density-dependent contact interaction. We investigate the spatial structure of two-neutron wave function in a Borromean nucleus $^{11}$Li.The behavior of the neutron pair at different densities is simulated by calculating the two-neutron wave function at several distances between the core nucleus $^9$Li and the center of mass of the two neutrons. With this representation, a strong concentration of the neutron pair on the nuclear surface is quantitatively established for neutron-rich nuclei. Dipole excitations in $^{6}$He and $^{11}$Li are also studied within the same three-body model and compared with experimental data. The small open angles between the two neutrons from the core are extracted empirically by the B(E1) sum rule together with the rms mass radii, indicating the strong di-neutron correlation in the halo nuclei.

  7. Catalytic, Asymmetric r-Halogenation Harald Wack, Andrew E. Taggi, Ahmed M. Hafez,

    E-Print Network [OSTI]

    Lectka, Thomas

    reported "relay" deprotonation strategy,5 in which protons are shuttled from the chiral amine catalyst Phenylacetyl chloride 1a was used as a test substrate to screen the various halogenating agents using 10 mol

  8. On mini-halo encounters with stars

    E-Print Network [OSTI]

    Anne M. Green; Simon P. Goodwin

    2006-12-11

    We study, analytically and numerically, the energy input into dark matter mini-haloes by interactions with stars. We find that the fractional energy input in simulations of Plummer spheres agrees well with the impulse approximation for small and large impact parameters, with a rapid transition between these two regimes. Using the impulse approximation the fractional energy input at large impact parameters is fairly independent of the mass and density profile of the mini-halo, however low-mass mini-haloes experience a greater fractional energy input in close encounters. We formulate a fitting function which encodes these results and use it to estimate the disruption timescales of mini-haloes, taking into account the stellar velocity dispersion and mass distribution. For mini-haloes with mass M< {\\cal O}(10^{-7} M_{\\odot} on typical orbits which pass through the disc, we find that the estimated disruption timescales are independent of mini-halo mass, and are of order the age of the Milky Way. For more massive mini-haloes the estimated disruption timescales increase rapidly with increasing mass.

  9. Conformastationary disk-haloes in Einstein-Maxwell gravity II. The physical interpretation of the halo

    E-Print Network [OSTI]

    Antonio C. Gutiérrez-Piñeres; Abraão Capistrano

    2014-12-18

    The relativistic treatment of galaxies modelled as a rotating disk surrounded by a magnetised material halo is considered. The galactic halo is modelled by a magnetised mass-energy distribution described by the energy-momentum tensor of a general fluid in canonical form. All the dynamics quantities characterising the physical of the halo are expressed in exact form in terms of an arbitrary solution of the Laplace's equation. By way of illustration, a "generalisation" of the Kuzmin solution of the Laplace's equation is used. The motion of a charged particle on the halo region is described. All the relevant quantities and the motion of the charged particle show a reasonable physical behaviour.

  10. Environmental Dependence of Dark Matter Halo Growth I: Halo Merger Rates

    E-Print Network [OSTI]

    Onsi Fakhouri; Chung-Pei Ma

    2009-01-23

    In an earlier paper we quantified the mean merger rate of dark matter haloes as a function of redshift z, descendant halo mass M0, and progenitor halo mass ratio xi using the Millennium simulation of the LCDM cosmology. Here we broaden that study and investigate the dependence of the merger rate of haloes on their surrounding environment. A number of local mass overdensity variables, both including and excluding the halo mass itself, are tested as measures of a halo's environment. The simple functional dependence on z, M0, and xi of the merger rate found in our earlier work is largely preserved in different environments, but we find that the overall amplitude of the merger rate has a strong positive correlation with the environmental densities. For galaxy-mass haloes, we find mergers to occur ~2.5 times more frequently in the densest regions than in voids at both z=0 and higher redshifts. Higher-mass haloes show similar trends. We present a fitting form for this environmental dependence that is a function of both mass and local density and is valid out to z=2. The amplitude of the progenitor (or conditional) mass function shows a similarly strong correlation with local overdensity, suggesting that the extended Press-Schechter model for halo growth needs to be modified to incorporate environmental effects.

  11. Exact Relativistic Magnetized halos around Rotating Disks

    E-Print Network [OSTI]

    Antonio C. Gutiérrez-Piñeres; Abraão J. S. Capistrano

    2015-05-15

    The exact relativistic treatment of a rotating disk surrounded by a magnetized material halo is presented. The features of the halo and disk are described by the distributional energy-momentum tensor of a general fluid in canonical form. All the relevant quantities and the metric and electromagnetic potentials are exactly determined by an arbitrary harmonic function only. For instance, the generalized Kuzmin-disk potential is used. The particular class of solutions obtained is asymptotically flat and satisfies all the energy conditions. Moreover, the motion of a charged particle on the halo is described. As far as we know, this is the first relativistic model describing analytically the magnetized halo of a rotating disk.

  12. Halo occupation numbers and galaxy bias

    E-Print Network [OSTI]

    J. A. Peacock; R. E. Smith

    2000-06-30

    We propose a heuristic model that displays the main features of realistic theories for galaxy bias. We show that the low-order clustering statistics of the dark-matter distribution depend almost entirely on the locations and density profiles of dark-matter haloes. A hypothetical galaxy catalogue depends on (i) the efficiency of galaxy formation, as manifested by the halo occupation number -- the number of galaxies brighter than some sample limit contained in a halo of a given mass; (ii) the location of these galaxies within their halo. The first factor is constrained by the empirical luminosity function of groups. For the second factor, we assume that one galaxy marks the halo centre, with any remaining galaxies acting as satellites that trace the halo mass. These simple assumptions amount to a recipe for non-local bias, in which the probability of finding a galaxy is not a simple function of its local mass density. We have applied this prescription to some CDM models of current interest, and find that the predictions are close to the observed galaxy correlations for a flat $\\Omega=0.3$ model ($\\Lambda$CDM), but not for an $\\Omega=1$ model with the same power spectrum ($\\tau$CDM). This is an inevitable consequence of cluster normalization for the power spectra: cluster-scale haloes of given mass have smaller core radii for high $\\Omega$, and hence display enhanced small-scale clustering. Finally, the pairwise velocity dispersion of galaxies in the $\\Lambda$CDM model is lower than that of the mass, allowing cluster-normalized models to yield a realistic Mach number for the peculiar velocity field. This is largely due to the strong variation of galaxy-formation efficiency with halo mass that is required in this model.

  13. Halo Formation in Warm Dark Matter Models

    E-Print Network [OSTI]

    Paul Bode; Jeremiah P. Ostriker; Neil Turok

    2001-05-29

    Discrepancies have emerged between the predictions of standard cold dark matter (CDM) theory and observations of clustering on sub-galactic scales. Warm dark matter (WDM) is a simple modification of CDM in which the dark matter particles have initial velocities due either to their having decoupled as thermal relics, or having been formed via non-equilibrium decay. We investigate the nonlinear gravitational clustering of WDM with a high resolution N-body code, and identify a number of distinctive observational signatures. Relative to CDM, halo concentrations and core densities are lowered, core radii are increased, and large halos emerge with far fewer low mass satellites. The number of small halos is suppressed, and those present are formed by `top down' fragmentation of caustics, as part of a `cosmic web' connecting massive halos. Few small halos form outside this web. If we identify small halos with dwarf galaxies, their number, spatial distribution, and formation epoch appear in better agreement with the observations for WDM than they are for CDM.

  14. Analysis of Halogen-Mercury Reactions in Flue Gas

    SciTech Connect (OSTI)

    Paula Buitrago; Geoffrey Silcox; Constance Senior; Brydger Van Otten

    2010-01-01

    Oxidized mercury species may be formed in combustion systems through gas-phase reactions between elemental mercury and halogens, such as chorine or bromine. This study examines how bromine species affect mercury oxidation in the gas phase and examines the effects of mixtures of bromine and chlorine on extents of oxidation. Experiments were conducted in a bench-scale, laminar flow, methane-fired (300 W), quartz-lined reactor in which gas composition (HCl, HBr, NO{sub x}, SO{sub 2}) and temperature profile were varied. In the experiments, the post-combustion gases were quenched from flame temperatures to about 350 C, and then speciated mercury was measured using a wet conditioning system and continuous emissions monitor (CEM). Supporting kinetic calculations were performed and compared with measured levels of oxidation. A significant portion of this report is devoted to sample conditioning as part of the mercury analysis system. In combustion systems with significant amounts of Br{sub 2} in the flue gas, the impinger solutions used to speciate mercury may be biased and care must be taken in interpreting mercury oxidation results. The stannous chloride solution used in the CEM conditioning system to convert all mercury to total mercury did not provide complete conversion of oxidized mercury to elemental, when bromine was added to the combustion system, resulting in a low bias for the total mercury measurement. The use of a hydroxylamine hydrochloride and sodium hydroxide solution instead of stannous chloride showed a significant improvement in the measurement of total mercury. Bromine was shown to be much more effective in the post-flame, homogeneous oxidation of mercury than chlorine, on an equivalent molar basis. Addition of NO to the flame (up to 400 ppmv) had no impact on mercury oxidation by chlorine or bromine. Addition of SO{sub 2} had no effect on mercury oxidation by chlorine at SO{sub 2} concentrations below about 400 ppmv; some increase in mercury oxidation was observed at SO{sub 2} concentrations of 400 ppmv and higher. In contrast, SO{sub 2} concentrations as low as 50 ppmv significantly reduced mercury oxidation by bromine, this reduction could be due to both gas and liquid phase interactions between SO{sub 2} and oxidized mercury species. The simultaneous presence of chlorine and bromine in the flue gas resulted in a slight increase in mercury oxidation above that obtained with bromine alone, the extent of the observed increase is proportional to the chlorine concentration. The results of this study can be used to understand the relative importance of gas-phase mercury oxidation by bromine and chlorine in combustion systems. Two temperature profiles were tested: a low quench (210 K/s) and a high quench (440 K/s). For chlorine the effects of quench rate were slight and hard to characterize with confidence. Oxidation with bromine proved sensitive to quench rate with significantly more oxidation at the lower rate. The data generated in this program are the first homogeneous laboratory-scale data on bromine-induced oxidation of mercury in a combustion system. Five Hg-Cl and three Hg-Br mechanisms, some published and others under development, were evaluated and compared to the new data. The Hg-halogen mechanisms were combined with submechanisms from Reaction Engineering International for NO{sub x}, SO{sub x}, and hydrocarbons. The homogeneous kinetics under-predicted the levels of mercury oxidation observed in full-scale systems. This shortcoming can be corrected by including heterogeneous kinetics in the model calculations.

  15. Process for removing halogenated aliphatic and aromatic compounds from petroleum products

    DOE Patents [OSTI]

    Googin, John M. (Oak Ridge, TN); Napier, John M. (Oak Ridge, TN); Travaglini, Michael A. (Oliver Springs, TN)

    1983-01-01

    A process for removing halogenated aliphatic and aromatic compounds, e.g., polychlorinated biphenyls, from petroleum products by solvent extraction. The halogenated aliphatic and aromatic compounds are extracted from a petroleum product into a polar solvent by contacting the petroleum product with the polar solvent. The polar solvent is characterized by a high solubility for the extracted halogenated aliphatic and aromatic compounds, a low solubility for the petroleum product and considerable solvent power for polyhydroxy compound. The preferred polar solvent is dimethylformamide. A miscible compound, such as, water or a polyhydroxy compound, is added to the polar extraction solvent to increase the polarity of the polar extraction solvent. The halogenated aliphatic and aromatic compounds are extracted from the highly-polarized mixture of water or polyhydroxy compound and polar extraction solvent into a low polar or nonpolar solvent by contacting the water or polyhydroxy compound-polar solvent mixture with the low polar or nonpolar solvent. The halogenated aliphatic and aromatic compounds and the low polar or nonpolar solvent are separated by physical means, e.g., vacuum evaporation. The polar and nonpolar solvents are recovered from recycling. The process can easily be designed for continuous operation. Advantages of the process include that the polar solvent and a major portion of the nonpolar solvent can be recycled, the petroleum products are reclaimable and the cost for disposing of waste containing polychlorinated biphenyls is significantly reduced.

  16. Process for removing halogenated aliphatic and aromatic compounds from petroleum products

    DOE Patents [OSTI]

    Googin, J.M.; Napier, J.M.; Travaglini, M.A.

    1983-09-20

    A process is described for removing halogenated aliphatic and aromatic compounds, e.g., polychlorinated biphenyls, from petroleum products by solvent extraction. The halogenated aliphatic and aromatic compounds are extracted from a petroleum product into a polar solvent by contacting the petroleum product with the polar solvent. The polar solvent is characterized by a high solubility for the extracted halogenated aliphatic and aromatic compounds, a low solubility for the petroleum product and considerable solvent power for polyhydroxy compound. The preferred polar solvent is dimethylformamide. A miscible compound, such as, water or a polyhydroxy compound, is added to the polar extraction solvent to increase the polarity of the polar extraction solvent. The halogenated aliphatic and aromatic compounds are extracted from the highly-polarized mixture of water or polyhydroxy compound and polar extraction solvent into a low polar or nonpolar solvent by contacting the water or polyhydroxy compound-polar solvent mixture with the low polar or nonpolar solvent. The halogenated aliphatic and aromatic compounds and the low polar or nonpolar solvent are separated by physical means, e.g., vacuum evaporation. The polar and nonpolar solvents are recovered from recycling. The process can easily be designed for continuous operation. Advantages of the process include that the polar solvent and a major portion of the nonpolar solvent can be recycled, the petroleum products are reclaimable and the cost for disposing of waste containing polychlorinated biphenyls is significantly reduced. 1 fig.

  17. Two Stellar Components in the Halo of the Milky Way

    E-Print Network [OSTI]

    D. Carollo; T. C. Beers; Y. S. Lee; M. Chiba; J. E. Norris; R. Wilhelm; T. Sivarani; B. Marsteller; J. A. Munn; C. A. L. Bailer-Jones; P. Re Fiorentin; D. G. York

    2007-12-16

    The halo of the Milky Way provides unique elemental abundance and kinematic information on the first objects to form in the Universe, which can be used to tightly constrain models of galaxy formation and evolution. Although the halo was once considered a single component, evidence for its dichotomy has slowly emerged in recent years from inspection of small samples of halo objects. Here we show that the halo is indeed clearly divisible into two broadly overlapping structural components -- an inner and an outer halo -- that exhibit different spatial density profiles, stellar orbits and stellar metallicities (abundances of elements heavier than helium). The inner halo has a modest net prograde rotation, whereas the outer halo exhibits a net retrograde rotation and a peak metallicity one-third that of the inner halo. These properties indicate that the individual halo components probably formed in fundamentally different ways, through successive dissipational (inner) and dissipationless (outer) mergers and tidal disruption of proto-Galactic clumps.

  18. Microlensing Implications for Halo Dark Matter

    E-Print Network [OSTI]

    Philippe Jetzer; Eduard Masso

    1996-01-23

    The most accurate way to get information on the mass of the MACHOs (Massive Astrophysical Compact Halo Objects) is to use the method of mass moments. For the microlensing events detected so far by the EROS and the MACHO collaborations in the Large Magellanic Cloud the average mass turns out to be 0.08$M_{\\odot}$. Assuming a spherical standard halo model we find that MACHOs contribute about 20\\% to the halo dark matter. The eleven events recorded by OGLE, mainly during its first two years of operation, in the galactic bulge lead to an average mass of 0.29$M_{\\odot}$, whereas forty events detected by MACHO during its first year give 0.16$M_{\\odot}$, thus suggesting that the lens objects are faint disk stars.

  19. Range corrections in Proton Halo Nuclei

    E-Print Network [OSTI]

    Ryberg, Emil; Hammer, H -W; Platter, Lucas

    2015-01-01

    We analyze the effects of finite-range corrections in halo effective field theory for S-wave proton halo nuclei. We calculate the charge radius to next-to-leading order and the astrophysical S-factor for low-energy proton capture to fifth order in the low-energy expansion. As an application, we confront our results with experimental data for the S-factor for proton capture on Oxygen-16 into the excited $1/2^+$ state of Fluorine-17. Our low-energy theory is characterized by a systematic low-energy expansion, which can be used to quantify an energy-dependent model error to be utilized in data fitting. Finally, we show that the existence of proton halos is suppressed by the need for two fine tunings in the underlying theory.

  20. The Mass-Function of Low Mass Halo Stars: Limits on Baryonic Halo Dark Matter

    E-Print Network [OSTI]

    David S. Graff; Katherine Freese

    1996-06-18

    We derive mass functions (MF) for halo red dwarfs (the faintest hydrogen burning stars) and then extrapolate to place limits on the total mass of halo brown dwarfs (stars not quite massive enough to burn hydrogen). The mass functions are obtained from the luminosity function of a sample of 114 local halo stars in the USNO parallax survey (Dahn \\etal 1995). We use stellar models of Alexander \\etal (1996) and make varying assumptions about metallicity and about possible unresolved binaries in the sample. We find that the MF for halo red dwarfs cannot rise more quickly than $1/m^2$ as one approaches the hydrogen burning limit. Using recent results from star formation theory, we extrapolate the MF into the brown-dwarf regime. We see that likely extrapolations imply that the total mass of brown dwarfs in the halo is less than $\\sim 3\\%$ of the local mass density of the halo ($\\sim 0.3\\%$ for the more realistic models we consider). Our limits apply to brown dwarfs in the halo that come from the same stellar population as the red dwarfs.

  1. Dark halo properties from rotation curves

    E-Print Network [OSTI]

    Raul Jimenez; Licia Verde; S. Peng Oh

    2002-01-21

    We study a large set of high spatial resolution optical rotation curves of galaxies with the goal of determining the model parameters for a disk embedded within a CDM halo that we model either with a NFW profile or pseudo-isothermal profile. We show that parameter degeneracies present in lower resolution data are lifted at these higher resolutions. 34% of the galaxies do not have a meaningful fit when using the NFW profile and 32% when using the pseudoisothermal profile, however only 14% do not have a meaningful fit in either model. In both models we find correlations between the disk baryon fraction $f_d$ and the spin parameter of the halo $\\lambda'$, between $f_d$ and the dark halo mass $M_{200}$, and between $M_{200}$ and the concentration parameter $c$. We show that the distribution of the concentration parameters $c$, for a NFW halo, is in good agreement with CDM predictions; no significant galaxy population is found with very low values of $c$. The overall distribution of $\\lambda'$ is in good agreement with theoretical predictions from hierarchical tidal torque theory. The whole sample is also well fitted by a pseudo-isothermal dark halo with a core, but the size of the core is rather small (for 70% of the sample the core size is less than 2 kpc). Thus we conclude that the profile of dark matter is steep ($r^{-1}$ or steeper) down to this radius; large dark matter cores (and therefore very low dark matter central densities) seem to be excluded. LSBs tend to have higher values of $\\lambda'$ for a given $f_d$ and lower values of $c$ for a given mass than HSBs. In an appendix we give some useful formula for pseudo-isothermal profile halos and discuss in detail the issue of parameter degeneracies.

  2. LED lamp or bulb with remote phosphor and diffuser configuration with enhanced scattering properties

    DOE Patents [OSTI]

    Tong, Tao; Le Toquin, Ronan; Keller, Bernd; Tarsa, Eric; Youmans, Mark; Lowes, Theodore; Medendorp, Jr., Nicholas W; Van De Ven, Antony; Negley, Gerald

    2014-11-11

    An LED lamp or bulb is disclosed that comprises a light source, a heat sink structure and an optical cavity. The optical cavity comprises a phosphor carrier having a conversions material and arranged over an opening to the cavity. The phosphor carrier comprises a thermally conductive transparent material and is thermally coupled to the heat sink structure. An LED based light source is mounted in the optical cavity remote to the phosphor carrier with light from the light source passing through the phosphor carrier. A diffuser dome is included that is mounted over the optical cavity, with light from the optical cavity passing through the diffuser dome. The properties of the diffuser, such as geometry, scattering properties of the scattering layer, surface roughness or smoothness, and spatial distribution of the scattering layer properties may be used to control various lamp properties such as color uniformity and light intensity distribution as a function of viewing angle.

  3. Laser photochemical etching of molybdenum and tungsten thin films by surface halogenation

    SciTech Connect (OSTI)

    Rothschild, M.; Sedlacek, J.H.; Ehrlich, D.J.

    1986-12-01

    Laser direct-write etching of the refractory metals Mo and W was developed using reactions in chlorine and nitrogen trifluoride vapors. Rate and high spatial resolution are simultaneously optimized using a two-vapor halogenation/development sequence, based on surface modification. Local-area laser chlorination of the metal surface is used to predispose areas to subsequent bulk etching.

  4. Nanoparticle halos: A new colloid stabilization mechanism

    E-Print Network [OSTI]

    Braun, Paul

    Nanoparticle halos: A new colloid stabilization mechanism Valeria Tohver*, James E. Smay*, Alan, 2001 (received for review February 7, 2001) A new mechanism for regulating the stability of colloidal for tailoring the behavior of com- plex fluids. Colloidal suspensions enjoy widespread use in applications

  5. Non-Gaussian halo mass function and non-spherical halo collapse: theory vs. simulations

    SciTech Connect (OSTI)

    Achitouv, Ixandra E.; Corasaniti, Pier Stefano, E-mail: Ixandra.Achitouv@obspm.fr, E-mail: Pier-Stefano.Corasaniti@obspm.fr [Laboratoire Univers et Théories (LUTh), UMR 8102 CNRS, Observatoire de Paris, Université Paris Diderot, 5 Place Jules Janssen, 92190 Meudon (France)

    2012-02-01

    The mass distribution of dark matter halos is a sensitive probe of primordial non-Gaussianity (NG). We derive an analytical formula of the halo mass function by perturbatively computing excursion set path-integrals for a non-Gaussian density field with non-vanishing skewness, f{sub NL}. We assume a stochastic barrier model which captures the main features of the ellipsoidal collapse of halos. Contrary to previous results based on extensions of the Press-Schechter formalism to NG initial conditions, we find that the non-spherical collapse of halos directly alter the signature of primordial NG. This points toward a potential degeneracy between the effect of primordial non-Gaussianity and that of non-linear halo collapse. The inferred mass function is found to be in remarkable agreement with N-body simulations of NG local type. Deviations are well within numerical uncertainties for all values of f{sub NL}{sup loc} in the range of validity of the perturbative calculation (|f{sub nl}{sup loc}|?<200). Moreover, the comparison with simulation results suggests that for |f{sub NL}|?>30 the non-linear collapse of halos, as described by our barrier model, strongly deviates from that of Gaussian initial conditions. This is not surprising since the effect of non-linear gravitational processes may be altered by initially large NG. Hence, in the lack of prior theoretical knowledge, halo collapse model parameters should be included in statistical halo mass function data analysis which aim to constrain the signature of primordial NG.

  6. Baryonic pinching of galactic dark matter halos

    SciTech Connect (OSTI)

    Gustafsson, Michael; Fairbairn, Malcolm; Sommer-Larsen, Jesper [Cosmology, Particle Astrophysics and String Theory, Department of Physics, Stockholm University, AlbaNova University Center, SE-106 91, Stockholm (Sweden); Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark)

    2006-12-15

    High resolution cosmological N-body simulations of four galaxy-scale dark matter halos are compared to corresponding N-body/hydrodynamical simulations containing dark matter, stars and gas. The simulations without baryons share features with others described in the literature in that the dark matter density slope continuously decreases towards the center, with a density {rho}{sub DM}{proportional_to}r{sup -1.3{+-}}{sup 0.2}, at about 1% of the virial radius for our Milky Way sized galaxies. The central cusps in the simulations which also contain baryons steepen significantly, to {rho}{sub DM}{proportional_to}r{sup -1.9{+-}}{sup 0.2}, with an indication of the inner logarithmic slope converging. Models of adiabatic contraction of dark matter halos due to the central buildup of stellar/gaseous galaxies are examined. The simplest and most commonly used model, by Blumenthal et al., is shown to overestimate the central dark matter density considerably. A modified model proposed by Gnedin et al. is tested and it is shown that, while it is a considerable improvement, it is not perfect. Moreover, it is found that the contraction parameters in their model not only depend on the orbital structure of the dark-matter-only halos but also on the stellar feedback prescription which is most relevant for the baryonic distribution. Implications for dark matter annihilation at the galactic center are discussed and it is found that, although our simulations show a considerable reduced dark matter halo contraction as compared to the Blumenthal et al. model, the fluxes from dark matter annihilation are still expected to be enhanced by at least a factor of a hundred, as compared to dark-matter-only halos. Finally, it is shown that, while dark-matter-only halos are typically prolate, the dark matter halos containing baryons are mildly oblate with minor-to-major axis ratios of c/a=0.73{+-}0.11, with their flattening aligned with the central baryonic disks.

  7. Dynamics of the Disruption Halo Current Toroidal Asymmetry in NSTX

    SciTech Connect (OSTI)

    S.P. Gerhardt

    2012-09-27

    This paper describes the dynamics of disruption halo current non-axisymmetries in the lower divertor of the National Spherical Torus Experiment [M. Ono, et al. Nuclear Fusion 40, 557 (2000)]. While. The halo currents typically have a strongly asymmetric structure where they enter the divertor floor, and this asymmetry has been observed to complete up to 7 toroidal revolutions over the duration of the halo current pulse. However, the rotation speed and toroidal extend of the asymmetry can vary significantly during the pulse. The rotation speed, halo current pulse duration, and total number of revolutions tend to be smaller in cases with large halo currents. The halo current pattern is observed to become toroidally symmetric at the end of the halo current pulse. It is proposed that this symmeterization is due to the loss of most or all of the closed field line geometry in the final phase of the vertical displacement event.

  8. Visualization of nitric oxide production in the mouse main olfactory bulb by a cell-trappable copper(II) fluorescent probe

    E-Print Network [OSTI]

    McQuade, Lindsey E.

    We report the visualization of NO production using fluorescence in tissue slices of the mouse main olfactory bulb. This discovery was possible through the use of a novel, cell-trappable probe for intracellular nitric oxide ...

  9. Halogens in the coastal snow pack near Barrow, Alaska: Evidence for active bromine air-snow chemistry during springtime

    E-Print Network [OSTI]

    Domine, Florent

    . Frost flowers have been proposed as an important intermediate step in halogen activation [Rankin et al with organic compounds, such as aldehydes, leading to HBr and HCl. These acids are then scavenged by snow

  10. Spherical collapse in Galileon gravity: fifth force solutions, halo mass function and halo bias

    SciTech Connect (OSTI)

    Barreira, Alexandre; Li, Baojiu; Baugh, Carlton M.; Pascoli, Silvia E-mail: liqb@mail.ihep.ac.cn E-mail: silvia.pascoli@durham.ac.uk

    2013-11-01

    We study spherical collapse in the Quartic and Quintic Covariant Galileon gravity models within the framework of the excursion set formalism. We derive the nonlinear spherically symmetric equations in the quasi-static and weak-field limits, focusing on model parameters that fit current CMB, SNIa and BAO data. We demonstrate that the equations of the Quintic model do not admit physical solutions of the fifth force in high density regions, which prevents the study of structure formation in this model. For the Quartic model, we show that the effective gravitational strength deviates from the standard value at late times (z?<1), becoming larger if the density is low, but smaller if the density is high. This shows that the Vainshtein mechanism at high densities is not enough to screen all of the modifications of gravity. This makes halos that collapse at z?<1 feel an overall weaker gravity, which suppresses halo formation. However, the matter density in the Quartic model is higher than in standard ?CDM, which boosts structure formation and dominates over the effect of the weaker gravity. In the Quartic model there is a significant overabundance of high-mass halos relative to ?CDM. Dark matter halos are also less biased than in ?CDM, with the difference increasing appreciably with halo mass. However, our results suggest that the bias may not be small enough to fully reconcile the predicted matter power spectrum with LRG clustering data.

  11. How many principles does it take to change a light bulb ... into a laser?

    E-Print Network [OSTI]

    Wiseman, Howard M

    2015-01-01

    Quantum optics did not, and could not, flourish without the laser. The present paper is not about the principles of laser construction, still less a history of how the laser was invented. Rather, it addresses the question: what are the fundamental features that distinguish laser light from thermal light? The answers do, however, show, in a quantitative way --- involving, indeed, very large dimensionless quantities (up to $\\sim 10^{51}$) --- that a laser must be constructed very differently from a light bulb. Some of this paper is based on material I use to introduce advanced undergraduate students to quantum optics. The theory presented is mostly quite simple, and yet it is not to be found in any text-books on quantum optics to my knowledge. The obvious answer, ``laser light is coherent'', is, I argue, so vague that it must be put aside at the start, albeit to revisit later. A specific version, ``laser light is in a coherent state'', is simply wrong in this context, since both laser light and thermal light ca...

  12. r-Process Enhanced Halo Stars

    E-Print Network [OSTI]

    J. J. Cowan; C. Sneden; J. E. Lawler; E. A. Den Hartog

    2006-10-13

    Abundance observations indicate the presence of rapid-neutron capture (i.e., r-process) elements in old Galactic halo and globular cluster stars. These observations provide insight into the nature of the earliest generations of stars in the Galaxy -- the progenitors of the halo stars -- responsible for neutron-capture synthesis of the heavy elements. The large star-to-star scatter observed in the abundances of neutron-capture element/iron ratios at low metallicities -- which diminishes with increasing metallicity or [Fe/H] -- suggests the formation of these heavy elements (presumably from certain types of supernovae) was rare in the early Galaxy. The stellar abundances also indicate a change from the r-process to the slow neutron capture (i.e., s-) process at higher metallicities in the Galaxy and provide insight into Galactic chemical evolution. Finally, the detection of thorium and uranium in halo and globular cluster stars offers an independent age-dating technique that can put lower limits on the age of the Galaxy, and hence the Universe.

  13. Spectral irradiance model for tungsten halogen lamps in 340-850 nm wavelength range

    SciTech Connect (OSTI)

    Ojanen, Maija; Kaerhae, Petri; Ikonen, Erkki

    2010-02-10

    We have developed a physical model for the spectral irradiance of 1 kW tungsten halogen incandescent lamps for the wavelength range 340-850 nm. The model consists of the Planck's radiation law, published values for the emissivity of tungsten, and a residual spectral correction function taking into account unknown factors of the lamp. The correction function was determined by measuring the spectra of a 1000 W, quartz-halogen, tungsten coiled filament (FEL) lamp at different temperatures. The new model was tested with lamps of types FEL and 1000 W, 120 V quartz halogen (DXW). Comparisons with measurements of two national standards laboratories indicate that the model can account for the spectral irradiance values of lamps with an agreement better than 1% throughout the spectral region studied. We further demonstrate that the spectral irradiance of a lamp can be predicted with an expanded uncertainty of 2.6% if the color temperature and illuminance values for the lamp are known with expanded uncertainties of 20 K and 2%, respectively. In addition, it is suggested that the spectral irradiance may be derived from resistance measurements of the filament with lamp on and off.

  14. Scaling Evolution of Universal Dark-Matter Halo Density Profiles

    E-Print Network [OSTI]

    A. Raig; G. Gonzalez-Casado; E. Salvador-Sole

    1998-10-10

    Dark-matter halos show a universal density profile with a scaling such that less massive systems are typically denser. This mass-density relation is well described by a proportionality between the characteristic density of halos and the mean cosmic density at halo formation time. It has recently been shown that this proportionality could be the result of the following simple evolutionary picture. Halos form in major mergers with essentially the same, cosmogony-dependent, dimensionless profile, and then grow inside-outside, as a consequence of accretion. Here we verify the consistency of this picture and show that it predicts the correct zero point of the mass-density relation.

  15. Mergers and Mass Accretion for Infalling Halos Both End Well...

    Office of Scientific and Technical Information (OSTI)

    Halos Both End Well Outside Cluster Virial Radii Authors: Behroozi, Peter S. ; Baltimore, Space Telescope Sci. Stanford U., Phys. Dept. SLAC KIPAC, Menlo Park ; Wechsler,...

  16. The effect of early dark matter halos on reionization

    E-Print Network [OSTI]

    Aravind Natarajan; Dominik J. Schwarz

    2008-11-21

    The annihilation of dark matter particles releases energy, ionizing some of the gas in the Universe. We investigate the effect of dark matter halos on reionization. We show that the effect depends on the assumed density profile, the particle mass, and the assumed minimum halo mass. For NFW halos and typical WIMPs, we find the effect to be quite small. However, light dark matter candidates in the MeV range can contribute significantly to reionization and can make an important contribution to the measured optical depth. This effect may be used to constrain light dark matter models. We also study the effect of varying the halo density profile on reionization.

  17. School Energy Survey Teacher Guide

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

    Key Student Guide Page 20 INCANDESCENT BULB HALOGEN COMPACT FLUORESCENT (CFL) LIGHT EMITTING DIODE (LED) Number of bulbs to get 25,000 hours 25 8.3 2.5 1 Cost of bulbs for 25,000...

  18. How many principles does it take to change a light bulb ... into a laser?

    E-Print Network [OSTI]

    Howard M. Wiseman

    2015-10-16

    Quantum optics did not, and could not, flourish without the laser. The present paper is not about the principles of laser construction, still less a history of how the laser was invented. Rather, it addresses the question: what are the fundamental features that distinguish laser light from thermal light? The answers do, however, show, in a quantitative way --- involving, indeed, very large dimensionless quantities (up to $\\sim 10^{51}$) --- that a laser must be constructed very differently from a light bulb. Some of this paper is based on material I use to introduce advanced undergraduate students to quantum optics. The theory presented is mostly quite simple, and yet it is not to be found in any text-books on quantum optics to my knowledge. The obvious answer, ``laser light is coherent'', is, I argue, so vague that it must be put aside at the start, albeit to revisit later. A specific version, ``laser light is in a coherent state'', is simply wrong in this context, since both laser light and thermal light can be described by a coherent state, though necessarily one that varies stochastically in space. Nevertheless, this perspective does reveal a profound difference between them, in that this description (a stochastically varying coherent state) is the only simple description of a laser beam. Interestingly, this implies the (perhaps new) prediction that narrowly filtered laser beams are indistinguishable from similarly filtered thermal beams. I hope that other educators find this material useful; it may contain surprises even for researchers who have been in the field longer than I have. But I cannot finish the abstract without answering the titular question: four --- high directionality, monochromaticity, high brightness, and stable intensity.

  19. COMPOSITION OF LOW-REDSHIFT HALO GAS

    SciTech Connect (OSTI)

    Cen Renyue

    2013-06-20

    Halo gas in low-z (z < 0.5) {>=}0.1 L{sub *} galaxies in high-resolution, large-scale cosmological hydrodynamic simulations is examined with respect to three components: cold, warm, and hot with temperatures of <10{sup 5}, 10{sup 5-6}, and >10{sup 6} K, respectively. Utilizing O VI {lambda}{lambda}1032, 1038 absorption lines, the warm component is compared to observations, and agreement is found with respect to the galaxy-O VI line correlation, the ratio of the O VI line incidence rate in blue to red galaxies, and the amount of O VI mass in star-forming galaxies. A detailed account of the sources of warm halo gas (stellar feedback heating, gravitational shock heating, and accretion from the intergalactic medium), inflowing and outflowing warm halo gas metallicity disparities, and their dependencies on galaxy types and environment is also presented. With the warm component securely anchored, our simulations make the following additional predictions. First, cold gas is the primary component in inner regions with its mass comprising 50% of all gas within galactocentric radius r = (30, 150) kpc in (red, blue) galaxies. Second, at r > (30, 200) kpc in (red, blue) galaxies the hot component becomes the majority. Third, the warm component is a perpetual minority, with its contribution peaking at {approx}30% at r = 100-300 kpc in blue galaxies and never exceeding 5% in red galaxies. The significant amount of cold gas in low-z early-type galaxies, which was found in simulations and in agreement with recent observations (Thom et al.), is intriguing, as is the dominance of hot gas at large radii in blue galaxies.

  20. Splashback in accreting dark matter halos

    SciTech Connect (OSTI)

    Adhikari, Susmita; Dalal, Neal; Chamberlain, Robert T. E-mail: dalaln@illinois.edu

    2014-11-01

    Recent work has shown that density profiles in the outskirts of dark matter halos can become extremely steep over a narrow range of radius. This behavior is produced by splashback material on its first apocentric passage after accretion. We show that the location of this splashback feature may be understood quite simply, from first principles. We present a simple model, based on spherical collapse, that accurately predicts the location of splashback without any free parameters. The important quantities that determine the splashback radius are accretion rate and redshift.

  1. Clustering and Correlations in Neutron Haloes

    E-Print Network [OSTI]

    N. A. Orr

    2002-01-25

    In the present paper clustering and correlations within halo systems is explored. In particular, the application of neutron-neutron interferometry and Dalitz-plot type analyses is presented through the example provided by the dissociation of 14Be. A novel approach for producing and detecting bound neutron clusters is also described. The observation of some 6 events with characteristics consistent with the liberation of a multineutron cluster in the breakup of 14Be -- possibly in the channel 10Be+4n -- is discussed.

  2. The halo-model description of marked statistics

    E-Print Network [OSTI]

    Ravi K. Sheth

    2005-11-28

    Marked statistics allow sensitive tests of how galaxy properties correlate with environment, as well as of how correlations between galaxy properties are affected by environment. A halo-model description of marked correlations is developed, which incorporates the effects which arise from the facts that typical galaxy marks (e.g., luminosity, color, star formation rate, stellar mass) depend on the mass of the parent halo, and that massive haloes extend to larger radii and populate denser regions. Comparison with measured marked statistics in semi-analytic galaxy formation models shows good agreement on scales smaller than a Megaparsec, and excellent agreement on larger scales. The halo-model description shows clearly that the behaviour of some low-order marked statistics on these scales encodes information about the mean galaxy mark as a function of halo mass, but is insensitive to mark-gradients within haloes. Higher-order statistics encode information about higher order moments of the distribution of marks within haloes. This information is obtained without ever having to identify haloes or clusters in the galaxy distribution. On scales smaller than a Megaparsec, the halo-model calculation shows that marked statistics allow sensitive tests of whether or not central galaxies in haloes are a special population. A prescription for including more general mark-gradients in the halo-model description is also provided. The formalism developed here is particularly well-suited to interpretation of marked statistics in astrophysical datasets, because it is phrased in the same language that is currently used to interpret more standard measures of galaxy clustering.

  3. Environmental Dependence of Cold Dark Matter Halo Formation

    E-Print Network [OSTI]

    H. Y. Wang; H. J. Mo; Y. P. Jing

    2006-11-21

    We use a high-resolution $N$-body simulation to study how the formation of cold dark matter (CDM) halos is affected by their environments, and how such environmental effects produce the age-dependence of halo clustering observed in recent $N$-body simulations. We estimate, for each halo selected at redshift $z=0$, an `initial' mass $M_{\\rm i}$ defined to be the mass enclosed by the largest sphere which contains the initial barycenter of the halo particles and within which the mean linear density is equal to the critical value for spherical collapse at $z=0$. For halos of a given final mass, $M_{\\rm h}$, the ratio $M_{\\rm i}/M_{\\rm h}$ has large scatter, and the scatter is larger for halos of lower final masses. Halos that form earlier on average have larger $M_{\\rm i}/M_{\\rm h}$, and so correspond to higher peaks in the initial density field than their final masses imply. Old halos are more strongly clustered than younger ones of the same mass because their initial masses are larger. The age-dependence of clustering for low-mass halos is entirely due to the difference in the initial/final mass ratio. Low-mass old halos are almost always located in the vicinity of big structures, and their old ages are largely due to the fact that their mass accretions are suppressed by the hot environments produced by the tidal fields of the larger structure. The age-dependence of clustering is weaker for more massive halos because the heating by large-scale tidal fields is less important.

  4. Process for removing halogenated aliphatic and aromatic compounds from petroleum products. [Polychlorinated biphenyls; methylene chloride; perchloroethylene; trichlorofluoroethane; trichloroethylene; chlorobenzene

    DOE Patents [OSTI]

    Googin, J.M.; Napier, J.M.; Travaglini, M.A.

    1982-03-31

    A process for removing halogenated aliphatic and aromatic compounds, e.g., polychlorinated biphenyls, from petroleum products by solvent extraction. The halogenated aliphatic and aromatic compounds are extracted from a petroleum product into a polar solvent by contracting the petroleum product with the polar solvent. The polar solvent is characterized by a high solubility for the extracted halogenated aliphatic and aromatic compounds, a low solubility for the petroleum product and considerable solvent power for polyhydroxy compound. The preferred polar solvent is dimethylformamide. A miscible polyhydroxy compound, such as, water, is added to the polar extraction solvent to increase the polarity of the polar extraction solvent. The halogenated aliphatic and aromatic compounds are extracted from the highly-polarized mixture of polyhydroxy compound and polar extraction solvent into a low polar or nonpolar solvent by contacting the polyhydroxy compound-polar solvent mixture with the low polar or nonpolar solvent. The halogenated aliphatic and aromatic compounds in the low polar or nonpolar solvent by physical means, e.g., vacuum evaporation. The polar and nonpolar solvents are recovered for recycling. The process can easily be designed for continuous operation. Advantages of the process include that the polar solvent and a major portion of the nonpolar solvent can be recycled, the petroleum products are reclaimable and the cost for disposing of waste containing polychlorinated biphenyls is significantly reduced. 2 tables.

  5. Merger vs. Accretion and the Structure of Dark Matter Halos

    E-Print Network [OSTI]

    E. Salvador-Sole; A. Manrique; J. M. Solanes

    1997-12-05

    High-resolution N-body simulations of hierarchical clustering in a wide variety of cosmogonies show that the density profiles of dark matter halos are universal, with low mass halos being denser than their more massive counterparts. This mass-density correlation is interpreted as reflecting the earlier typical formation time of less massive objects. We investigate this hypothesis in the light of formation times defined as the epoch at which halos experience their last major merger. Such halo formation times are calculated by means of a modification of the extended Press & Schechter formalism which includes a phenomenological frontier, Delta_m, between tiny and notable relative mass captures leading to the distinction between merger and accretion. For Delta_m=0.6, we confirm that the characteristic density of halos is essentially proportional to the mean density of the universe at their time of formation. Yet, proportionality with respect to the critical density yields slightly better results for open universes. In addition, we find that the scale radius of halos is also essentially proportional to their virial radius at the time of formation. We show that these two relations are consistent with the following simple scenario. Violent relaxation caused by mergers rearranges the structure of halos leading to the same density profile with universal values of the dimensionless characteristic density and scale radius. Between mergers, halos grow gradually through the accretion of surrounding layers by keeping their central parts steady and expanding their virial radius as the critical density of the universe diminishes.

  6. Scale Radii and Aggregation Histories of Dark Haloes

    E-Print Network [OSTI]

    Eduard Salvador-Sole; Alberto Manrique; Jose M. Solanes

    2005-01-21

    Relaxed dark-matter haloes are found to exhibit the same universal density profiles regardless of whether they form in hierarchical cosmologies or via spherical collapse. Likewise, the shape parameters of haloes formed hierarchically do not seem to depend on the epoch in which the last major merger took place. Both findings suggest that the density profile of haloes does not depend on their aggregation history. Yet, this possibility is apparently at odds with some correlations involving the scale radius r_s found in numerical simulations. Here we prove that the scale radius of relaxed, non-rotating, spherically symmetric haloes endowed with the universal density profile is determined exclusively by the current values of four independent, though correlated, quantities: mass, energy and their respective instantaneous accretion rates. Under this premise and taking into account the inside-out growth of haloes during the accretion phase between major mergers, we build a simple physical model for the evolution of r_s along the main branch of halo merger trees that reproduces all the empirical trends shown by this parameter in N-body simulations. This confirms the conclusion that the empirical correlations involving r_s do not actually imply the dependence of this parameter on the halo aggregation history. The present results give strong support to the explanation put forward in a recent paper by Manrique et al. (2003) for the origin of the halo universal density profile.

  7. SECULAR DAMPING OF STELLAR BARS IN SPINNING DARK MATTER HALOS

    SciTech Connect (OSTI)

    Long, Stacy; Shlosman, Isaac [Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506-0055 (United States); Heller, Clayton [Department of Physics, Georgia Southern University, Statesboro, GA 30460 (United States)

    2014-03-01

    We demonstrate using numerical simulations of isolated galaxies that growth of stellar bars in spinning dark matter halos is heavily suppressed in the secular phase of evolution. In a representative set of models, we show that for values of the cosmological spin parameter ? ? 0.03, bar growth (in strength and size) becomes increasingly quenched. Furthermore, the slowdown of the bar pattern speed weakens considerably with increasing ? until it ceases completely. The terminal structure of the bars is affected as well, including extent and shape of their boxy/peanut bulges. The essence of this effect lies in the modified angular momentum exchange between the disk and the halo facilitated by the bar. For the first time we have demonstrated that a dark matter halo can emit and not purely absorb angular momentum. Although the halo as a whole is not found to emit, the net transfer of angular momentum from the disk to the halo is significantly reduced or completely eliminated. The paradigm shift implies that the accepted view that disks serve as sources of angular momentum and halos serve as sinks must be revised. Halos with ? ? 0.03 are expected to form a substantial fraction, based on the lognormal distribution of ?. The dependence of secular bar evolution on halo spin, therefore, implies profound corollaries for the cosmological evolution of galactic disks.

  8. The prolate dark matter halo of the Andromeda galaxy

    SciTech Connect (OSTI)

    Hayashi, Kohei; Chiba, Masashi E-mail: chiba@astr.tohoku.ac.jp

    2014-07-01

    We present new limits on the global shape of the dark matter halo in the Andromeda galaxy using and generalizing non-spherical mass models developed by Hayashi and Chiba and compare our results with theoretical predictions of cold dark matter (CDM) models. This is motivated by the fact that CDM models predict non-spherical virialized dark halos, which reflect the process of mass assembly in the galactic scale. Applying our models to the latest kinematic data of globular clusters and dwarf spheroidal galaxies in the Andromeda halo, we find that the most plausible cases for Andromeda yield a prolate shape for its dark halo, irrespective of assumed density profiles. We also find that this prolate dark halo in Andromeda is consistent with theoretical predictions in which the satellites are distributed anisotropically and preferentially located along major axes of their host halos. It is a reflection of the intimate connection between galactic dark matter halos and the cosmic web. Therefore, our result is profound in understanding internal dynamics of halo tracers in Andromeda, such as orbital evolutions of tidal stellar streams, which play important roles in extracting the abundance of CDM subhalos through their dynamical effects on stream structures.

  9. MACHO (MAssive Compact Halo Objects) Data

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

    The primary aim of the MACHO Project is to test the hypothesis that a significant fraction of the dark matter in the halo of the Milky Way is made up of objects like brown dwarfs or planets: these objects have come to be known as MACHOs, for MAssive Compact Halo Objects. The signature of these objects is the occasional amplification of the light from extragalactic stars by the gravitational lens effect. The amplification can be large, but events are extremely rare: it is necessary to monitor photometrically several million stars for a period of years in order to obtain a useful detection rate. For this purpose MACHO has a two channel system that employs eight CCDs, mounted on the 50 inch telescope at Mt. Stromlo. The high data rate (several GBytes per night) is accommodated by custom electronics and on-line data reduction. The Project has taken more than 27,000 images with this system since June 1992. Analysis of a subset of these data has yielded databases containing light curves in two colors for 8 million stars in the LMC and 10 million in the bulge of the Milky Way. A search for microlensing has turned up four candidates toward the Large Magellanic Cloud and 45 toward the Galactic Bulge. The web page for data provides links to MACHO Project data portals and various specialized interfaces for viewing or searching the data. (Specialized Interface)

  10. The CMS Beam Halo Monitor Detector System

    E-Print Network [OSTI]

    Stifter, Kelly

    2015-01-01

    A new Beam Halo Monitor (BHM) detector system has been installed in the CMS cavern to measure the machine-induced background (MIB) from the LHC. This background originates from interactions of the LHC beam halo with the final set of collimators before the CMS experiment and from beam gas interactions. The BHM detector uses the directional nature of Cherenkov radiation and event timing to select particles coming from the direction of the beam and to suppress those originating from the interaction point. It consists of 40 quartz rods, placed on each side of the CMS detector, coupled to UV sensitive PMTs. For each bunch crossing the PMT signal is digitized by a charge integrating ASIC and the arrival time of the signal is recorded. The data are processed in real time to yield a precise measurement of per-bunch-crossing background rate. This measurement is made available to CMS and the LHC, to provide real-time feedback on the beam quality and to improve the efficiency of data taking. Here, I present the detector...

  11. Why are Halo Density Profiles Stable at Formation?

    E-Print Network [OSTI]

    G. Gonzalez-Casado; A. Raig; E. Salvador-Sole

    1998-10-28

    We analyze the physical justification of the picture proposed by Salvador-Sole et al. in these proceedings for the time evolution of the universal density profile of dark-matter halos. According to this picture, halos have at formation a stable (i.e. independent of mass and time) dimensionless density profile, the characteristic length and density scales of the profile depending on the underlying cosmogony. Subsequent evolution is driven by mass accretion onto the outskirts of halos and can be characterized simply by the increment of halo radius with time and the corresponding decrease of the critical density of the universe. We find this picture to be a reasonable good description of the expected evolution of halos in hierarchical models of structure formation.

  12. [?/Fe] ABUNDANCES OF FOUR OUTER M31 HALO STARS

    SciTech Connect (OSTI)

    Vargas, Luis C.; Geha, Marla; Tollerud, Erik J. [Department of Astronomy, Yale University, 260 Whitney Avenue, New Haven, CT 06511 (United States); Gilbert, Karoline M. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Kirby, Evan N. [California Institute of Technology, 1200 East California Boulevard, MC 249-17, Pasadena, CA 91125 (United States); Guhathakurta, Puragra, E-mail: luis.vargas@yale.edu [UCO/Lick Observatory and Department of Astronomy and Astrophysics, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States)

    2014-12-10

    We present alpha element to iron abundance ratios, [?/Fe], for four stars in the outer stellar halo of the Andromeda Galaxy (M31). The stars were identified as high-likelihood field halo stars by Gilbert et al. and lie at projected distances between 70 and 140 kpc from M31's center. These are the first alpha abundances measured for a halo star in a galaxy beyond the Milky Way. The stars range in metallicity between [Fe/H] = –2.2 and [Fe/H] = –1.4. The sample's average [?/Fe] ratio is +0.20 ± 0.20. The best-fit average value is elevated above solar, which is consistent with rapid chemical enrichment from Type II supernovae. The mean [?/Fe] ratio of our M31 outer halo sample agrees (within the uncertainties) with that of Milky Way inner/outer halo stars that have a comparable range of [Fe/H].

  13. The halo model in a massive neutrino cosmology

    E-Print Network [OSTI]

    Elena Massara; Francisco Villaescusa-Navarro; Matteo Viel

    2015-01-20

    We provide a quantitative analysis of the halo model in the context of massive neutrino cosmologies. We discuss all the ingredients necessary to model the non-linear matter and cold dark matter power spectra and compare with the results of N-body simulations that incorporate massive neutrinos. Our neutrino halo model is able to capture the non-linear behavior of matter clustering with a $\\sim 20\\%$ accuracy up to very non-linear scales of $k=10~h/$Mpc (which would be affected by baryon physics). The largest discrepancies arise in the range $k=0.5-1~h/$Mpc where the 1-halo and 2-halo terms are comparable and are present also in a massless neutrino cosmology. However, at scales $kOccupation Distribution scheme and our halo model extension.

  14. The alignment of dark matter halos with the cosmic web

    E-Print Network [OSTI]

    Santiago G. Patiri; Antonio J. Cuesta; Francisco Prada; Juan Betancort-Rijo; Anatoly Klypin

    2006-10-23

    We investigate the orientation of the axes and angular momentum of dark matter halos with respect to their neighboring voids using high resolution N-body cosmological simulations. We find that the minor axis of halos tends to be aligned along the line joining the halo with the center of the void, and that the major axis is perpendicular to this line. However, we find that the angular momentum of halos does not have any particular orientation. These results may provide information about the mechanisms whereby the large-scale structure of the Universe affects galaxy formation and cast light upon the issue of the orientation of galaxy disks with respect to their host halos.

  15. Sensitivity of Tropospheric Chemical Composition to Halogen-Radical Chemistry Using a Fully Coupled Size-Resolved Multiphase Chemistry-Global Climate System: Halogen Distributions, Aerosol Composition, and Sensitivity of Climate-Relevant Gases

    SciTech Connect (OSTI)

    Long, M.; Keene, W. C.; Easter, Richard C.; Sander, Rolf; Liu, Xiaohong; Kerkweg, A.; Erickson, D.

    2014-04-07

    Observations and model studies suggest a significant but highly non-linear role for halogens, primarily Cl and Br, in multiphase atmospheric processes relevant to tropospheric chemistry and composition, aerosol evolution, radiative transfer, weather, and climate. The sensitivity of global atmospheric chemistry to the production of marine aerosol and the associated activation and cycling of inorganic Cl and Br was tested using a size-resolved multiphase coupled chemistry/global climate model (National Center for Atmospheric Research’s Community Atmosphere Model (CAM); v3.6.33). Simulation results showed strong meridional and vertical gradients in Cl and Br species. The simulation reproduced most available observations with reasonable confidence permitting the formulation of potential mechanisms for several previously unexplained halogen phenomena including the enrichment of Br- in submicron aerosol, and the presence of a BrO maximum in the polar free troposphere. However, simulated total volatile Br mixing ratios were generally high in the troposphere. Br in the stratosphere was lower than observed due to the lack of long-lived organobromine species in the simulation. Comparing simulations using chemical mechanisms with and without reactive Cl and Br species demonstrated a significant temporal and spatial sensitivity of primary atmospheric oxidants (O3, HOx, NOx), CH4, and non-methane hydrocarbons (NMHC’s) to halogen cycling. Simulated O3 and NOx were globally lower (65% and 35%, respectively, less in the planetary boundary layer based on median values) in simulations that included halogens. Globally, little impact was seen in SO2 and non-sea-salt SO42- processing due to halogens. Significant regional differences were evident: The lifetime of nss-SO42- was extended downwind of large sources of SO2. The burden and lifetime of DMS (and its oxidation products) were lower by a factor of 5 in simulations that included halogens, versus those without, leading to a 20% reduction in nss-SO42- in the southern hemisphere planetary boundary layer based on median values.

  16. Quantum spin coherence in halogen-modified Cr$_7$Ni molecular nanomagnets

    E-Print Network [OSTI]

    Danielle Kaminski; Amy L. Webber; Christopher J. Wedge; Junjie Liu; Grigore A. Timco; Inigo J. Vitorica-Yrezabal; Eric J. L. McInnes; Richard E. P. Winpenny; Arzhang Ardavan

    2014-10-30

    Among the factors determining the quantum coherence of the spin in molecular magnets is the presence and the nature of nuclear spins in the molecule. We have explored modifying the nuclear spin environment in Cr$_7$Ni-based molecular nanomagnets by replacing hydrogen atoms with deuterium or the halogen atoms, fluorine or chlorine. We find that the spin coherence, studied at low temperatures by pulsed electron spin resonance, is modified by a range of factors, including nuclear spin and magnetic moment, changes in dynamics owing to nuclear mass, and molecular morphology changes.

  17. Roles of Oxygen and Water Vapor in the Oxidation of Halogen Terminated Ge(111) Surfaces

    SciTech Connect (OSTI)

    Sun, Shiyu; /Stanford U., Phys. Dept.; Sun, Yun; Liu, Zhi; Lee, Dong-Ick; Pianette, Piero; /SLAC, SSRL

    2006-12-18

    The initial stage of the oxidation of Cl and Br terminated Ge(111) surfaces is studied using photoelectron spectroscopy. The authors perform controlled experiments to differentiate the effects of different factors in oxidation, and find that water vapor and oxygen play different roles. Water vapor effectively replaces the halogen termination layers with the hydroxyl group, but does not oxidize the surfaces further. In contrast, little oxidation is observed for Cl and Br terminated surfaces with dry oxygen alone. However, with the help of water vapor, oxygen oxidizes the surface by breaking the Ge-Ge back bonds instead of changing the termination layer.

  18. Process for the solvent extraction for the radiolysis and dehalogenation of halogenated organic compounds in soils, sludges, sediments and slurries

    DOE Patents [OSTI]

    Golden, Jeffry

    2007-02-13

    A process of extracting halogenated organic compounds, and particularly PCBs, from soil, sediment, slurry, sludge and dehalogenating the compounds contacts a contaminated soil sample with an extraction medium of a mixture of an alkane and a water miscible alcohol. The organic compounds dissolve in the extraction medium which is separated from the soil by passing water upwardly through the soil. The extraction medium floats to the surface of the water and is separated. Thereafter, the extraction medium containing the halogenated organic contaminants is subjected to ionizing radiation to radiolytically dehalogenate the compounds.

  19. Process for the solvent extraction for the radiolysis and dehalogenation of halogenated organic compounds in soils, sludges, sediments and slurries

    DOE Patents [OSTI]

    Mincher, Bruce J. (3705 Creekside Dr., Idaho Falls, ID 83404); Curry, Randy Dale (1104 Merrill Ct., Columbia, MO 65203); Clevenger, Thomas E. (2512 Bluff Blvd., Columbia, MO 65201); Golden, Jeffry (12612 Cedarbrook La., Laurel, MD 20708)

    2000-01-01

    A process of extracting halogenated organic compounds, and particularly PCBs, from soil, sediment, slurry, sludge and dehalogenating the compounds contacting a contaminated soil sample with an extraction medium of a mixture of an alkane and a water miscible alcohol. The organic compounds dissolve in the extraction medium which is separated from the soil by passing water upwardly through the soil. The extraction medium floats to the surface of the water and is separated. Thereafter, the extraction medium containing the halogenated organic contaminants is subjected to ionizing radiation to radiolytically dehalogenate the compounds.

  20. Process for the solvent extraction for the radiolysis and dehalogenation of halogenated organic compounds in soils, sludges, sediments and slurries

    DOE Patents [OSTI]

    Mincher, Bruce J.; Curry, Randy Dale; Clevenger, Thomas E.; Golden, Jeffry

    2003-05-27

    A process of extracting halogenated organic compounds, and particularly PCBs, from soil, sediment, slurry, sludge and dehalogenating the compounds contacts a contaminated soil sample with an extraction medium of a mixture of an alkane and a water miscible alcohol. The organic compounds dissolve in the extraction medium which is separated from the soil by passing water upwardly through the soil. The extraction medium floats to the surface of the water and is separated. Thereafter, the extraction medium containing the halogenated organic contaminants is subjected to ionizing radiation to radiolytically dehalogenate the compounds.

  1. Optimal linear reconstruction of dark matter from halo catalogues

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

    Cai, Yan -Chuan; Bernstein, Gary; Sheth, Ravi K.

    2011-04-01

    The dark matter lumps (or "halos") that contain galaxies have locations in the Universe that are to some extent random with respect to the overall matter distributions. We investigate how best to estimate the total matter distribution from the locations of the halos. We derive the weight function w(M) to apply to dark-matter haloes that minimizes the stochasticity between the weighted halo distribution and its underlying mass density field. The optimal w(M) depends on the range of masses of halos being used. While the standard biased-Poisson model of the halo distribution predicts that bias weighting is optimal, the simple factmore »that the mass is comprised of haloes implies that the optimal w(M) will be a mixture of mass-weighting and bias-weighting. In N-body simulations, the Poisson estimator is up to 15× noisier than the optimal. Optimal weighting could make cosmological tests based on the matter power spectrum or cross-correlations much more powerful and/or cost effective.« less

  2. Optimal linear reconstruction of dark matter from halo catalogues

    SciTech Connect (OSTI)

    Cai, Yan -Chuan; Bernstein, Gary; Sheth, Ravi K.

    2011-04-01

    The dark matter lumps (or "halos") that contain galaxies have locations in the Universe that are to some extent random with respect to the overall matter distributions. We investigate how best to estimate the total matter distribution from the locations of the halos. We derive the weight function w(M) to apply to dark-matter haloes that minimizes the stochasticity between the weighted halo distribution and its underlying mass density field. The optimal w(M) depends on the range of masses of halos being used. While the standard biased-Poisson model of the halo distribution predicts that bias weighting is optimal, the simple fact that the mass is comprised of haloes implies that the optimal w(M) will be a mixture of mass-weighting and bias-weighting. In N-body simulations, the Poisson estimator is up to 15× noisier than the optimal. Optimal weighting could make cosmological tests based on the matter power spectrum or cross-correlations much more powerful and/or cost effective.

  3. Galactosynthesis: Halo Histories, Star Formation, and Disks

    E-Print Network [OSTI]

    Ari Buchalter; Raul Jimenez; Marc Kamionkowski

    2000-06-01

    We investigate the effects of a variety of ingredients that must enter into a realistic model for disk-galaxy formation, focusing primarily on the Tully-Fisher (TF) relation and its scatter in several wavebands. Our main findings are: (a) the slope, normalization, and scatter of the TF relation across various wavebands is determined {\\em both} by halo properties and star formation in the disk; (b) TF scatter owes primarily to the spread in formation redshifts. The scatter can be measurably reduced by chemical evolution, and also in some cases by the weak anti-correlation between peak height and spin; (c) multi-wavelength constraints can be important in distinguishing between models which appear to fit the TF relation in I or K; (d) successful models seem to require that the bulk of disk formation cannot occur too early (z>2) or too late (z<0.5), and are inconsistent with high values of $\\Omega_0$; (e) a realistic model with the above ingredients can reasonably reproduce the observed z=0 TF relation in {\\em all} bands (B, R, I, and K). It can also account for the z=1 B-band TF relation and yield rough agreement with the local B and K luminosity functions and B-band surface-brightness--magnitude relation. The remarkable agreement with observations suggests that the amount of gas that is expelled or poured into a disk galaxy must be small, and that the specific angular momentum of the baryons must roughly equal that of the halo; there is little room for angular momentum transfer. In an appendix we present analytic fits to stellar-population synthesis models.

  4. The halo model in a massive neutrino cosmology

    SciTech Connect (OSTI)

    Massara, Elena; Villaescusa-Navarro, Francisco; Viel, Matteo E-mail: villaescusa@oats.inaf.it

    2014-12-01

    We provide a quantitative analysis of the halo model in the context of massive neutrino cosmologies. We discuss all the ingredients necessary to model the non-linear matter and cold dark matter power spectra and compare with the results of N-body simulations that incorporate massive neutrinos. Our neutrino halo model is able to capture the non-linear behavior of matter clustering with a ?20% accuracy up to very non-linear scales of k = 10 h/Mpc (which would be affected by baryon physics). The largest discrepancies arise in the range k = 0.5 – 1 h/Mpc where the 1-halo and 2-halo terms are comparable and are present also in a massless neutrino cosmology. However, at scales k < 0.2 h/Mpc our neutrino halo model agrees with the results of N-body simulations at the level of 8% for total neutrino masses of < 0.3 eV. We also model the neutrino non-linear density field as a sum of a linear and clustered component and predict the neutrino power spectrum and the cold dark matter-neutrino cross-power spectrum up to k = 1 h/Mpc with ?30% accuracy. For masses below 0.15 eV the neutrino halo model captures the neutrino induced suppression, casted in terms of matter power ratios between massive and massless scenarios, with a 2% agreement with the results of N-body/neutrino simulations. Finally, we provide a simple application of the halo model: the computation of the clustering of galaxies, in massless and massive neutrinos cosmologies, using a simple Halo Occupation Distribution scheme and our halo model extension.

  5. Radius of B-8 halo from the asymptotic normalization coefficient 

    E-Print Network [OSTI]

    Carstoiu, F.; Trache, L.; Gagliardi, Carl A.; Tribble, Robert E.; Mukhamedzhanov, AM.

    2001-01-01

    radius of the Be-7 core. This large value and the fact that the asymptotic part of the proton wave function contributes 85% to the rms radius are good sign that B-8 is a halo nucleus....

  6. Palladium-Catalyzed Amination of Unprotected Halo-7- azaindoles

    E-Print Network [OSTI]

    Henderson, Jaclyn L.

    Simple and efficient procedures for the Pd-catalyzed cross-coupling of primary and secondary amines with halo-7-azaindoles(pyrrolo[2,3-b]pyridine) are presented. Previously, no general method was available to ensure the ...

  7. Effects of halo substructure on the power spectrum and bispectrum

    E-Print Network [OSTI]

    Derek Dolney; Bhuvnesh Jain; Masahiro Takada

    2004-09-22

    We study the effects of halo substructure and a distribution in the concentration parameter of haloes on large-scale structure statistics. The effects on the power spectrum and bispectrum are studied on the smallest scales accessible from future surveys. We compare halo-model predictions with results based on N-body simulations, but also extend our predictions to 10-kpc scales which will be probed by future simulations. We find that weak-lensing surveys proposed for the coming decade can probe the power spectrum on small enough scales to detect substructure in massive haloes. We discuss the prospects of constraining the mass fraction in substructure in view of partial degeneracies with parameters such as the tilt and running of the primordial power spectrum.

  8. Positron Propagation and Fluxes from Neutralino Annihilation in the Halo

    E-Print Network [OSTI]

    Edward A. Baltz; Joakim Edsjo

    1998-08-21

    Supersymmetric neutralinos are one of the most promising candidates for the dark matter in the Universe. If they exist, they should make up some fraction of the Milky Way halo. We investigate the fluxes of positrons expected at the Earth from neutralino annihilation in the halo. Positron propagation is treated in a diffusion model including energy loss. The positron source function includes contributions from both continuum and monochromatic positrons. We find that, for a "canonical" halo model and propagation parameters, the fluxes are generally too low to be visible. Given the large uncertainties in both propagation and halo structure, it is however possible to obtain observable fluxes. We also investigate the shapes of the positron spectra, including fits to a feature indicated by the results of the HEAT experiment.

  9. Problem 7-3: The air enters with a dry-bulb temperature of 50 o F and, at 50% relative humidity, with a wet-

    E-Print Network [OSTI]

    of the power-plant Rankine cycle. The actual process evaporates enough water to increase the humidity ratio, with a wet- bulb temperature of 42 o F, according to the Psychrometric Chart (page 821). The main evaporative% relative humidity. This process would evaporate enough water to increase the humidity ratio from 0

  10. Red Galaxies from Hot Halos in Cosmological Hydro Simulations

    E-Print Network [OSTI]

    Gabor, Jared

    2012-01-01

    I highlight three results from cosmological hydrodynamic simulations that yield a realistic red sequence of galaxies: 1) Major galaxy mergers are not responsible for shutting off star-formation and forming the red sequence. Starvation in hot halos is. 2) Massive galaxies grow substantially (about a factor of 2 in mass) after being quenched, primarily via minor (1:5) mergers. 3) Hot halo quenching naturally explains why galaxies are red when they either (a) are massive or (b) live in dense environments.

  11. Cores and cusps in warm dark matter halos

    SciTech Connect (OSTI)

    Villaescusa-Navarro, Francisco [IFIC, Universidad de Valencia-CSIC, E-46071, Valencia (Spain); Dalal, Neal, E-mail: villa@ific.uv.es, E-mail: neal@cita.utoronto.ca [Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St. George St., Toronto, ON, M5S3H8 (Canada)

    2011-03-01

    The apparent presence of large core radii in Low Surface Brightness galaxies has been claimed as evidence in favor of warm dark matter. Here we show that WDM halos do not have cores that are large fractions of the halo size: typically, r{sub core}/r{sub 200}?<10{sup ?3}. This suggests an astrophysical origin for the large cores observed in these galaxies, as has been argued by other authors.

  12. DUAL HALOS AND FORMATION OF EARLY-TYPE GALAXIES

    SciTech Connect (OSTI)

    Park, Hong Soo; Lee, Myung Gyoon E-mail: mglee@astro.snu.ac.kr

    2013-08-20

    We present a determination of the two-dimensional shape parameters of the blue and red globular cluster systems (GCSs) in a large number of elliptical galaxies and lenticular galaxies (early-type galaxies, called ETGs). We use a homogeneous data set of the globular clusters in 23 ETGs obtained from the HST/ACS Virgo Cluster Survey. The position angles of both blue and red GCSs show a correlation with those of the stellar light distribution, showing that the major axes of the GCSs are well aligned with those of their host galaxies. However, the shapes of the red GCSs show a tight correlation with the stellar light distribution as well as with the rotation property of their host galaxies, while the shapes of the blue GCSs do much less. These provide clear geometric evidence that the origins of the blue and red globular clusters are distinct and that ETGs may have dual halos: a blue (metal-poor) halo and a red (metal-rich) halo. These two halos show significant differences in metallicity, structure, and kinematics, indicating that they are formed in two distinguishable ways. The red halos might have formed via dissipational processes with rotation, while the blue halos are through accretion.

  13. High energy halogen atom reactions activated by nuclear transformations. Progress report, February 15, 1980-February 14, 1981

    SciTech Connect (OSTI)

    Not Available

    1981-02-01

    The stereochemistry of high energy /sup 18/F, /sup 34m/Cl, and /sup 76/Br substitution reactions involving enantiomeric molecules in the gas and condensed phase is studied. The gas to condensed state transition in halogen high energy chemistry, involving chlorine, bromine, and iodine activated by the (n,..gamma..) and (I.T.) processes in halomethanes, saturated and unsaturated hydrocarbons is being investigated in more detail. Special attention is given to defining the nature of the enhancement yields in the condensed phase. High energy halogen reactions in liquid and frozen aqueous solutions of organic and biomolecular solutes are studied in an attempt to learn more about these reactions. The applications of high energy chemistry techniques and theory to neutron activation analysis of biological systems are being continued. Special attention is given to developing procedures for trace molecular determinations in biological systems. The applications of hot halogen atoms as indicators of solute-solute interactions in liquid and frozen aqueous solutions of halogenated bases and nucleosides are being developed. Experiments are designed to explain the mechanisms of the radioprotection offered biomolecular solutes trapped within the frozen ice lattice. Reactions of bromine and iodine activated by isomeric transition with halogenated biomolecular solutes in liquid and frozen aqueous solutions are studied. The high energy reactions of iodine with the isomers of pentene have been studied in low pressure gaseous systems employing additives and rare gas moderators and liquid systems. Reactivity of excited complex formation and structural effects of electrophilic iodine attack on the pi-bond systems are studied.

  14. Simulating the Carbon Footprint of Galactic Halos

    E-Print Network [OSTI]

    Bird, Simeon; Suresh, Joshua; Hernquist, Lars

    2015-01-01

    We use observations of CIV and CII absorption in background quasars to constrain the parameters of supernova feedback models based on the Illustris cosmological simulation. We compare our simulations to two CIV absorber surveys at z=2-4, spanning a column density range $10^{12} - 10^{15}$ cm$^{-2}$, and an equivalent width 0.1 - 2 \\AA, respectively. We find that reproducing results from the first survey requires that the energy per unit mass of the supernova feedback be increased by a factor of two over the Illustris feedback model. We suggest that winds which deposit a fraction of their energy into heating, rather than accelerating, the surrounding gas can achieve this without altering the star formation rate. However, even our most energetic wind models do not produce enough absorbers with a CIV equivalent width greater than 0.6 Angstrom to match the results of the second survey. We connect these absorbers to the most massive haloes present in our simulations, and suggest possible ways to alleviate the disc...

  15. In situ thermally enhanced biodegradation of petroleum fuel hydrocarbons and halogenated organic solvents

    DOE Patents [OSTI]

    Taylor, R.T.; Jackson, K.J.; Duba, A.G.; Chen, C.I.

    1998-05-19

    An in situ thermally enhanced microbial remediation strategy and a method for the biodegradation of toxic petroleum fuel hydrocarbon and halogenated organic solvent contaminants are described. The method utilizes nonpathogenic, thermophilic bacteria for the thermal biodegradation of toxic and carcinogenic contaminants, such as benzene, toluene, ethylbenzene and xylenes, from fuel leaks and the chlorinated ethenes, such as trichloroethylene, chlorinated ethanes, such as 1,1,1-trichloroethane, and chlorinated methanes, such as chloroform, from past solvent cleaning practices. The method relies on and takes advantage of the pre-existing heated conditions and the array of delivery/recovery wells that are created and in place following primary subsurface contaminant volatilization efforts via thermal approaches, such as dynamic underground steam-electrical heating. 21 figs.

  16. In situ thermally enhanced biodegradation of petroleum fuel hydrocarbons and halogenated organic solvents

    DOE Patents [OSTI]

    Taylor, Robert T. (Livermore, CA); Jackson, Kenneth J. (San Leandro, CA); Duba, Alfred G. (Livermore, CA); Chen, Ching-I (Danville, CA)

    1998-01-01

    An in situ thermally enhanced microbial remediation strategy and a method for the biodegradation of toxic petroleum fuel hydrocarbon and halogenated organic solvent contaminants. The method utilizes nonpathogenic, thermophilic bacteria for the thermal biodegradation of toxic and carcinogenic contaminants, such as benzene, toluene, ethylbenzene and xylenes, from fuel leaks and the chlorinated ethenes, such as trichloroethylene, chlorinated ethanes, such as 1,1,1-trichloroethane, and chlorinated methanes, such as chloroform, from past solvent cleaning practices. The method relies on and takes advantage of the pre-existing heated conditions and the array of delivery/recovery wells that are created and in place following primary subsurface contaminant volatilization efforts via thermal approaches, such as dynamic underground steam-electrical heating.

  17. Mechanism of the Initial Oxidation of Hydrogen andHalogen Terminated Ge(111) Surfaces in Air

    SciTech Connect (OSTI)

    Sun, Shiyu; /Stanford U., Phys. Dept.; Sun, Yun; Liu, Zhi; Lee, Dong-Ick; Pianetta, Piero; /SLAC, SSRL

    2006-08-23

    The initial stage of the oxidation of Ge(111) surfaces etched by HF, HCl and HBr solutions is systematically studied using synchrotron radiation photoelectron spectroscopy (SR-PES). We perform controlled experiments to differentiate the effects of different oxidation factors. SR-PES results show that both moisture and oxygen contribute to the oxidation of the surfaces; however, they play different roles in the oxidation process. Moisture effectively replaces the hydrogen and halogen termination layers with hydroxyl (OH), but hardly oxidizes the surfaces further. On the other hand, dry oxygen does not replace the termination layers, but breaks the Ge-Ge back bonds and oxidizes the substrates with the aid of moisture. In addition, room light enhances the oxidation rate significantly.

  18. DARK MATTER SUB-HALO COUNTS VIA STAR STREAM CROSSINGS

    SciTech Connect (OSTI)

    Carlberg, R. G., E-mail: carlberg@astro.utoronto.ca [Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4 (Canada)

    2012-03-20

    Dark matter sub-halos create gaps in the stellar streams orbiting in the halos of galaxies. We evaluate the sub-halo stream crossing integral with the guidance of simulations to find that the linear rate of gap creation, R{sub U}, in a typical cold dark matter (CDM) galactic halo at 100 kpc is R{sub U}{approx_equal}0.0066 M-hat{sub 8}{sup -0.35}kpc{sup -1}Gyr{sup -1}, where M-hat{sub 8}({identical_to} M-hat /10{sup 8} M{sub Sun }) is the minimum mass halo that creates a visible gap. The relation can be recast entirely in terms of observables, as R{sub U}{approx_equal}0.059w{sup -0.85}kpc{sup -1}Gyr{sup -1}, for w in kpc, normalized at 100 kpc. Using published data, the density of gaps is estimated for M31's NW stream and the Milky Way Pal 5 stream, Orphan stream, and Eastern Banded Structure. The estimated rates of gap creation all have errors of 50% or more due to uncertain dynamical ages and the relatively noisy stream density measurements. The gap-rate-width data are in good agreement with the CDM-predicted relation. The high density of gaps in the narrow streams requires a total halo population of 10{sup 5} sub-halos above a minimum mass of 10{sup 5} M{sub Sun }.

  19. On the Origin of the Internal Structure of Haloes

    E-Print Network [OSTI]

    A. Manrique; E. Salvador-Sole; A. Raig

    2002-01-08

    High-resolution N-body simulations of hierarchical cosmologies have shown that the density and velocity dispersion profiles of dark-matter haloes display well-definite universal forms whose origin remains unknown. In the present paper, we calculate the internal structure of haloes expected to arise in any such cosmologies by simply taking into account that halo growth proceeds through an alternate sequence of discrete major mergers and long periods of gentle accretion. Major mergers cause the violent relaxation of the system subject to the boundary conditions imposed by accreting layers beginning to fall in at that moment. Accretion makes the system develop inside-out from the previous seed according to the spherical infall model. The predicted structure is in very good agreement with the results of numerical simulations, particularly for moderate and low mass haloes. We find strong indications that the slight departure observed in more massive systems is not due to a poorer theoretical prediction, but to the more marked effects of the limited resolution used in the simulations on the empirical profiles. This may have important consequences on the reported universality of halo structure.

  20. Investigation of the Contamination of the Gould (2003) Halo Sample

    E-Print Network [OSTI]

    Andrew Gould

    2007-08-09

    A recent astroph posting argued that the Gould (2003a) halo sample is substantially contaminated with thick-disk stars, which would then ``wash out'' any signature of granularity in the halo velocity distribution due to streams. If correct, this would imply that the limits placed by Gould (2003b) on streams are not valid. Here I investigate such contamination using six different indicators: (1) morphology of the underlying reduced proper motion diagram used to select halo stars; (2) comparison of kinematic and parallax-based distance scales; (3) comparison of derived halo parameters for the Gould (2003a) sample with other determinations; (4) a precision color-color diagram for a random subsample; (5) the 3-dimensional velocity distribution of a random subsample; (6) metallicity distribution versus kinematic cuts on a random subsample. I estimate that the contamination is of order 2%. Thus, the upper limits on the density of nearby streams derived by Gould (2003b) remain valid. In particular, at 95% confidence, no more than 5% of local halo stars (within about 300 pc) are in any one coherent stream. Determining whether or not this local measurement is consistent with CDM remains an outstanding question.

  1. A new halo model for clusters of galaxies

    E-Print Network [OSTI]

    Scholz, Erhard

    2015-01-01

    This paper presents a model for the dark halos of galaxy clusters in the framework of Weyl geometric scalar tensor theory with a MOND-like approximation in the weak field static limit. The basics of this approach are introduced in the first part of the paper; then a three component halo model is derived (without presupposing prior knowledge of Weyl geometric gravity). The cluster halo is constituted by the scalar field energy and the phantom energy of the gravitational structure, thus transparent rather than "dark". It is completely determined by the baryonic mass distribution of hot gas and stars. The model is tested against recent observational data for 19 clusters. The total mass of Coma and 15 other clusters is correctly predicted on the basis of data on baryonic mass in the bounds of the error intervals (1 sigma); one cluster lies in the 2 sigma interval, two more in 3 sigma.

  2. Dark Matter Halos in a Secondary Infall Model

    E-Print Network [OSTI]

    A. Del Popolo; M. Gambera

    2004-01-29

    We calculate the density profiles of virialized halos in the case of structure evolving hierarchically from a scale-free Gaussian delta-field having a power spectrum $P(k)\\propto k^n$ in a Omega=1 Universe; we suppose that the initial density contrast profile around local maxima is given by the mean peak profile introduced by Bardeen et al. (1986 hereafter BBKS). We show both that the density profiles are not power-laws but have a logarithmic slope that increases from the inner halo to its outer parts and for n \\geq -1 are well approximated by Navarro et al. (1995, 1996, 1997) profile and the radius a, at which the slope alpha=-2, is a function of the mass of the halo and of the spectral index n.

  3. Mixing between high velocity clouds and the galactic halo

    SciTech Connect (OSTI)

    Gritton, Jeffrey A.; Shelton, Robin L.; Kwak, Kyujin E-mail: rls@physast.uga.edu

    2014-11-01

    In the Galactic halo, metal-bearing Galactic halo material mixes into high velocity clouds (HVCs) as they hydrodynamically interact. This interaction begins long before the clouds completely dissipate and long before they slow to the velocity of the Galactic material. In order to make quantitative estimates of the mixing efficiency and resulting metal enrichment of HVCs, we made detailed two- and three-dimensional simulations of cloud-interstellar medium interactions. Our simulations track the hydrodynamics and time-dependent ionization levels. They assume that the cloud originally has a warm temperature and extremely low metallicity while the surrounding medium has a high temperature, low density, and substantial metallicity, but our simulations can be generalized to other choices of initial metallicities. In our simulations, mixing between cloud and halo gas noticeably raises the metallicity of the high velocity material. We present plots of the mixing efficiency and metal enrichment as a function of time.

  4. The density profiles of hot galactic halo gas

    E-Print Network [OSTI]

    Steen H. Hansen; Jesper Sommer-Larsen

    2006-06-13

    Extended gas haloes around galaxies are a ubiquitous prediction of galaxy formation scenarios. However, the density profiles of this hot halo gas is virtually unknown, although various profiles have been suggested on theoretical grounds. In order to quantitatively address the gas profile, we compare galaxies from direct cosmological simulations with analytical solutions of the underlying gas equations. We find remarkable agreement between simulations and theoretical predictions. We present an expression for this gas profile with a non-trivial dependence on the total mass profile. This expression is useful when setting up equilibrium galaxy models for numerical experiments.

  5. Suppressed fusion cross section for neutron halo nuclei

    E-Print Network [OSTI]

    Makoto Ito; Kazuhiro Yabana; Takashi Nakatsukasa; Manabu Ueda

    2006-01-20

    Fusion reactions of neutron-halo nuclei are investigated theoretically with a three-body model. The time-dependent wave-packet method is used to solve the three-body Schrodinger equation. The halo neutron behaves as a spectator during the Coulomb dissociation process of the projectile. The fusion cross sections of 11Be-209Bi and 6He-238U are calculated and are compared with measurements. Our calculation indicates that the fusion cross section is slightly hindered by the presence of weakly bound neutrons.

  6. CDM substructure problemCDM substructure problem and starand star fomationfomation in dwarf halosin dwarf halos

    E-Print Network [OSTI]

    Maryland at College Park, University of

    --scale fluctuationsscale fluctuations Credit: Ben Moore http://www.nbody.net Hot dark matter Warm dark matter Cold dark of dark matterby changing properties of dark matter and erasing smalland erasing small--sized halosized halo #12;What makes small halos faint orWhat makes small halos faint or completely dark

  7. The Star Formation History in the Andromeda Halo

    E-Print Network [OSTI]

    Thomas M. Brown

    2003-08-18

    I present the preliminary results of a program to measure the star formation history in the halo of the Andromeda galaxy. Using the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope, we obtained the deepest optical images of the sky to date, in a field on the southeast minor axis of Andromeda, 51 arcmin (11 kpc) from the nucleus. The resulting color-magnitude diagram (CMD) contains approximately 300,000 stars and extends more than 1.5 mag below the main sequence turnoff, with 50% completeness at V=30.7 mag. We interpret this CMD using comparisons to ACS observations of five Galactic globular clusters through the same filters, and through chi-squared fitting to a finely-spaced grid of calibrated stellar population models. We find evidence for a major (approximately 30%) intermediate-age (6-8 Gyr) metal-rich ([Fe/H] > -0.5) population in the Andromeda halo, along with a significant old metal-poor population akin to that in the Milky Way halo. The large spread in ages suggests that the Andromeda halo formed as a result of a more violent merging history than that in our own Milky Way.

  8. ANALYSIS OF HUMIDITY HALOS AROUND TRADE WIND CUMULUS CLOUDS

    E-Print Network [OSTI]

    , in addition to those of the clouds themselves, which have an impact on the energy balance of the atmosphereANALYSIS OF HUMIDITY HALOS AROUND TRADE WIND CUMULUS CLOUDS M.-L. Lu, J. Wang, A. Freedman, H. H [vol. 60, 1041-1059 (2003)] Environmental Sciences Department Atmospheric Sciences Division Brookhaven

  9. Haloes and Clustering in Light, Neutron-Rich Nuclei

    E-Print Network [OSTI]

    N. A. Orr

    2001-08-24

    Clustering is a relatively widespread phenomena which takes on many guises across the nuclear landscape. Selected topics concerning the study of halo systems and clustering in light, neutron-rich nuclei are discussed here through illustrative examples taken from the Be isotopic chain.

  10. Neutron-Capture Element Trends in the Halo

    E-Print Network [OSTI]

    C. Sneden; J. J. Cowan; J. W. Truran

    2001-01-24

    In a brief review of abundances neutron-capture elements (Z > ~30) in metal-poor halo stars, attention is called to their star-to-star scatter, the dominance of r-process synthesis at lowest metallicities, the puzzle of the lighter members of this element group, and the possibility of a better r-/s-process discriminant.

  11. Empirical Constraints on Halo Profiles from Rotation Curves

    E-Print Network [OSTI]

    McGaugh, Stacy

    Galaxies in the Cosmic Web New Mexico State University, Las Cruces, 19 May 2006 #12;1. Global Correlations: Tully-Fisher 2. Intermediate radii: dark matter density 3. Small radii: cusp/core #12;Primary Sample 74 concentration in model independent fashion - ! no individual fits, just amplitude of dark halo V(R) #12;Begeman

  12. Spatially resolved spectroscopic studies of planetary nebulae and their halos

    E-Print Network [OSTI]

    an automated method has been developed that includes binning of simultaneously observed spec- tra, a careful subtraction of telluric lines and now also a correction for differential atmospheric refraction. The results of previous findings. In the view of radiation hydrodynamic models a hot halo can be the product

  13. HOT GAS HALOS IN EARLY-TYPE FIELD GALAXIES

    SciTech Connect (OSTI)

    Mulchaey, John S. [Observatories of the Carnegie Institution of Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Jeltema, Tesla E., E-mail: mulchaey@obs.carnegiescience.ed, E-mail: tesla@ucolick.or [UCO/Lick Observatories, 1156 High Street, Santa Cruz, CA 95064 (United States)

    2010-05-20

    We use Chandra and XMM-Newton to study the hot gas content in a sample of field early-type galaxies. We find that the L {sub X}-L {sub K} relationship is steeper for field galaxies than for comparable galaxies in groups and clusters. The low hot gas content of field galaxies with L {sub K} {approx_lt} L {sub *} suggests that internal processes such as supernovae-driven winds or active galactic nucleus feedback expel hot gas from low-mass galaxies. Such mechanisms may be less effective in groups and clusters where the presence of an intragroup or intracluster medium can confine outflowing material. In addition, galaxies in groups and clusters may be able to accrete gas from the ambient medium. While there is a population of L {sub K} {approx_lt} L {sub *} galaxies in groups and clusters that retain hot gas halos, some galaxies in these rich environments, including brighter galaxies, are largely devoid of hot gas. In these cases, the hot gas halos have likely been removed via ram pressure stripping. This suggests a very complex interplay between the intragroup/intracluster medium and hot gas halos of galaxies in rich environments, with the ambient medium helping to confine or even enhance the halos in some cases and acting to remove gas in others. In contrast, the hot gas content of more isolated galaxies is largely a function of the mass of the galaxy, with more massive galaxies able to maintain their halos, while in lower mass systems the hot gas escapes in outflowing winds.

  14. Haloes light and dark: dynamical models of the stellar halo and constraints on the mass of the Galaxy

    E-Print Network [OSTI]

    Williams, A A

    2015-01-01

    We develop a flexible set of action-based distribution functions (DFs) for stellar halos. The DFs have five free parameters, controlling the inner and outer density slope, break radius, flattening and anisotropy respectively. The DFs generate flattened stellar halos with a rapidly varying logarithmic slope in density, as well as a spherically aligned velocity ellipsoid with a long axis that points towards the Galactic centre - all attributes possessed by the stellar halo of the Milky Way. We use our action-based distribution function to model the blue horizontal branch stars extracted from the Sloan Digital Sky Survey as stellar halo tracers in a spherical Galactic potential. As the selection function is hard to model, we fix the density law from earlier studies and solve for the anisotropy and gravitational potential parameters. Our best fit model has a velocity anisotropy that becomes more radially anisotropic on moving outwards. It changes from $\\beta \\approx 0.4$ at Galactocentric radius of 15 kpc to $\\ap...

  15. Density waves in the shearing sheet IV. Interaction with a live dark halo

    E-Print Network [OSTI]

    B. Fuchs

    2004-03-01

    It is shown that if the self-gravitating shearing sheet, a model of a patch of a galactic disk, is embedded in a live dark halo, this has a strong effect on the dynamics of density waves in the sheet. I describe how the density waves and the halo interact via halo particles either on orbits in resonance with the wave or on non-resonant orbits. Contrary to expectation the presence of the halo leads to a very considerable enhancement of the amplitudes of the density waves in the shearing sheet. This effect appears to be the equivalent of the recently reported enhanced growth of bars in numerically simulated stellar disks embedded in live dark halos. Finally I discuss the transfer of linear momentum from a density wave in the sheet to the halo and show that it is mediated only by halo particles on resonant orbits.

  16. School Energy Survey Student Guide

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

    of 40 new power plants. INCANDESCENT BULB HALOGEN COMPACT FLUORESCENT (CFL) LIGHT EMITTING DIODE (LED) Brightness 850 lumens 850 lumens 850 lumens 850 lumens Life of Bulb 1,000...

  17. Separation of toxic metal ions, hydrophilic hydrocarbons, hydrophobic fuel and halogenated hydrocarbons and recovery of ethanol from a process stream

    DOE Patents [OSTI]

    Kansa, E.J.; Anderson, B.L.; Wijesinghe, A.M.; Viani, B.E.

    1999-05-25

    This invention provides a process to tremendously reduce the bulk volume of contaminants obtained from an effluent stream produced subsurface remediation. The chemicals used for the subsurface remediation are reclaimed for recycling to the remediation process. Additional reductions in contaminant bulk volume are achieved by the ultra-violet light destruction of halogenated hydrocarbons, and the complete oxidation of hydrophobic fuel hydrocarbons and hydrophilic hydrocarbons. The contaminated bulk volume will arise primarily from the disposal of the toxic metal ions. The entire process is modular, so if there are any technological breakthroughs in one or more of the component process modules, such modules can be readily replaced. 3 figs.

  18. Separation of toxic metal ions, hydrophilic hydrocarbons, hydrophobic fuel and halogenated hydrocarbons and recovery of ethanol from a process stream

    DOE Patents [OSTI]

    Kansa, Edward J. (Livermore, CA); Anderson, Brian L. (Lodi, CA); Wijesinghe, Ananda M. (Tracy, CA); Viani, Brian E. (Oakland, CA)

    1999-01-01

    This invention provides a process to tremendously reduce the bulk volume of contaminants obtained from an effluent stream produced subsurface remediation. The chemicals used for the subsurface remediation are reclaimed for recycling to the remediation process. Additional reductions in contaminant bulk volume are achieved by the ultra-violet light destruction of halogenated hydrocarbons, and the complete oxidation of hydrophobic fuel hydrocarbons and hydrophilic hydrocarbons. The contaminated bulk volume will arise primarily from the disposal of the toxic metal ions. The entire process is modular, so if there are any technological breakthroughs in one or more of the component process modules, such modules can be readily replaced.

  19. Dynamics of dark energy in collapsing halo of dark matter

    E-Print Network [OSTI]

    Tsizh, M

    2015-01-01

    We investigate the non-linear evolution of spherical density and velocity perturbations of dark matter and dark energy in the expanding Universe. For that we have used the conservation and Einstein equations to describe the evolution of gravitationally coupled inhomogeneities of dark matter, dark energy and radiation from linear stage in the early Universe to the non-linear one at the current epoch. The simple method of the numerical integration of the system of non-linear differential equations for evolution of the central part of halo is proposed. The results are presented for halo of cluster ($k=2$ Mpc$^{-1}$) and supercluster scales ($k=0.2$ Mpc$^{-1}$) and show that quintessential scalar field dark energy with small value of effective speed of sound $c_s<0.1$ can give noticeable impact on the formation of large scale structures in the expanding Universe.

  20. Neutron structure effects in the deuteron and one neutron halos

    E-Print Network [OSTI]

    M. Nowakowski; N. G. Kelkar; T. Mart

    2006-08-29

    Although the neutron (n) does not carry a total electric charge, its charge and magnetization distributions represented in momentum space by the electromagnetic form factors, $F_1^{(n)} (q^2)$ and $F_2^{(n)} (q^2)$, lead to an electromagnetic potential of the neutron. Using this fact, we calculate the electromagnetic corrections to the binding energy, $B_d$, of the deuteron and a one neutron halo nucleus (11Be), by evaluating the neutron-proton and the neutron-charged core (10Be) potential, respectively. The correction to $B_d$ (~9 keV) is comparable to that arising due to the inclusion of the $\\Delta$-isobar component in the deuteron wave function. In the case of the more loosely bound halo nucleus, 11Be, the correction is close to about 2 keV.

  1. The Century Survey Galactic Halo Project I: Stellar Spectral Analysis

    E-Print Network [OSTI]

    W. R. Brown; C. Allende Prieto; T. C. Beers; R. Wilhelm; M. J. Geller; S. J. Kenyon; M. J. Kurtz

    2003-05-21

    The Century Survey Galactic Halo Project is a photometric and spectroscopic survey from which we select relatively blue stars (V-R<0.30 mag) as probes of the Milky Way halo. The Survey strip spans the range of Galactic latitude 35halo, and to test the hierarchical model for the formation of the Galaxy. In this paper we discuss spectroscopy and multi-passband photometry for a sample of 764 blue stars in the Century Survey region. Our sample consists predominantly of A- and F-type stars. We describe our techniques for determination of radial velocities, effective temperatures, metallicities, and surface gravities. Based on these measurements, we derive distance estimates by comparison with a set of calibrated isochrones. We devote special attention to the classification of blue horizontal-branch stars, and compare the results obtained from the application of the techniques of Kinman et al., Wilhelm et al., and Clewley et al. We identify 55 blue horizontal-branch stars. Our large sample of stars also uncovers a number of unusual objects, including three carbon-enhanced stars, a late B-type star located 0.8 kpc above the Galactic plane, and a DZ white dwarf.

  2. Systematic uncertainties from halo asphericity in dark matter searches

    SciTech Connect (OSTI)

    Bernal, Nicolás; Forero-Romero, Jaime E.; Garani, Raghuveer; Palomares-Ruiz, Sergio E-mail: je.forero@uniandes.edu.co E-mail: sergio.palomares.ruiz@ific.uv.es

    2014-09-01

    Although commonly assumed to be spherical, dark matter halos are predicted to be non-spherical by N-body simulations and their asphericity has a potential impact on the systematic uncertainties in dark matter searches. The evaluation of these uncertainties is the main aim of this work, where we study the impact of aspherical dark matter density distributions in Milky-Way-like halos on direct and indirect searches. Using data from the large N-body cosmological simulation Bolshoi, we perform a statistical analysis and quantify the systematic uncertainties on the determination of local dark matter density and the so-called J factors for dark matter annihilations and decays from the galactic center. We find that, due to our ignorance about the extent of the non-sphericity of the Milky Way dark matter halo, systematic uncertainties can be as large as 35%, within the 95% most probable region, for a spherically averaged value for the local density of 0.3-0.4 GeV/cm {sup 3}. Similarly, systematic uncertainties on the J factors evaluated around the galactic center can be as large as 10% and 15%, within the 95% most probable region, for dark matter annihilations and decays, respectively.

  3. Neutralino Gamma-ray Signals from Accreting Halo Dark Matter

    E-Print Network [OSTI]

    Lars Bergstrom; Joakim Edsjo; Christofer Gunnarsson

    2000-12-15

    There is mounting evidence that a self-consistent model for particle cold dark matter has to take into consideration spatial inhomogeneities on sub-galactic scales seen, for instance, in high-resolution N-body simulations of structure formation. Also in more idealized, analytic models, there appear density enhancements in certain regions of the halo. We use the results from a recent N-body simulation of the Milky Way halo and investigate the gamma-ray flux which would be produced when a specific dark matter candidate, the neutralino, annihilates in regions of enhanced density. The clumpiness found on all scales in the simulation results in very strong gamma-ray signals which seem to already rule out some regions of the supersymmetric parameter space, and would be further probed by upcoming experiments, such as the GLAST gamma-ray satellite. As an orthogonal model of structure formation, we also consider Sikivie's simple infall model of dark matter which predicts that there should exist continuous regions of enhanced density, caustic rings, in the dark matter halo of the Milky Way. We find, however, that the gamma-ray signal from caustic rings is generally too small to be detectable.

  4. Halo Luminosity Function From Photometric Calibration of the Revised NLTT

    E-Print Network [OSTI]

    Andrew Gould; Juna A. Kollmeier; Julio Chaname; Samir Salim

    2004-12-30

    We calibrate the photographic photometry of the revised New Luyten Two-Tenths catalog (rNLTT) by matching 3448 rNLTT stars to the Sloan Digital Sky Survey (SDSS). The correction is linear in magnitude and goes from zero at V ~ 14 to 0.32 mag at V=19, in the sense that rNLTT was previously too bright. The correction implies that the underlying USNO-A2.0 photometry, on which rNLTT photometry is based, is non-linear. The new calibration somewhat improves the appearance of the (V,V-J) reduced proper motion diagram in the sense of better separation between disk and halo stars. We repeat Gould's analysis of 5000 halo stars in rNLTT. The most important change is to move the peak of the halo luminosity function about 0.5 mag dimmer, from M_V=10.5 to M_V=11, putting it into good agreement with the parallax-based determination of Dahn et al.

  5. WHAT TO BRING RIT Housing Operations

    E-Print Network [OSTI]

    Salvaggio, Carl

    Extension cords and multi-plug adapters Portable space heaters Halogen lamps and halogen bulbs 300 watts, or laundry basket (Ones that fold are best) Towels and washcloths Iron and small portable ironing board

  6. Life-Cycle Assessment of Energy and Environmental Impacts of...

    Office of Scientific and Technical Information (OSTI)

    Hollomon, Brad; Dillon, Heather E.; Snowden-Swan, Lesley J. LED; light-emitting diode; CFL; incandescent; halogen; lamp; bulb; TCLP; STLC; TTLC; WET; hazardous waste; electronic...

  7. "Title","Creator/Author","Publication Date","OSTI Identifier...

    Office of Scientific and Technical Information (OSTI)

    National Laboratory (PNNL), Richland, WA (US)","USDOE","LED; light-emitting diode; CFL; incandescent; halogen; lamp; bulb; TCLP; STLC; TTLC; WET; hazardous waste; electronic...

  8. Halos in a deformed relativistic Hartree-Bogoliubov theory in continuum

    SciTech Connect (OSTI)

    Li Lulu; Meng Jie; Ring, P.; Zhao Enguang; Zhou Shangui

    2012-10-20

    In this contribution we present some recent results about neutron halos in deformed nuclei. A deformed relativistic Hartree-Bogoliubov theory in continuumhas been developed and the halo phenomenon in deformed weakly bound nuclei is investigated. These weakly bound quantum systems present interesting examples for the study of the interdependence between the deformation of the core and the particles in the halo. Magnesium and neon isotopes are studied and detailed results are presented for the deformed neutron-rich and weakly bound nuclei {sup 42}Mg. The core of this nucleus is prolate, but the halo has a slightly oblate shape. This indicates a decoupling of the halo orbitals from the deformation of the core. The generic conditions for the existence of halos in deformed nuclei and for the occurrence of this decoupling effect are discussed.

  9. Comparing Light Bulbs

    Office of Energy Efficiency and Renewable Energy (EERE)

    In this exercise, students will use a light to demonstrate the difference between being energy-efficient and energy-wasteful, and learn what energy efficiency means.

  10. THE DUAL ORIGIN OF STELLAR HALOS. II. CHEMICAL ABUNDANCES AS TRACERS OF FORMATION HISTORY

    SciTech Connect (OSTI)

    Zolotov, Adi; Hogg, David W. [Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Willman, Beth [Haverford College, Department of Astronomy, 370 Lancaster Avenue, Haverford, PA 19041 (United States); Brooks, Alyson M. [California Institute of Technology, M/C 350-17, Pasadena, CA 91125 (United States); Governato, Fabio [Department of Astronomy, University of Washington, P.O. Box 351580, Seattle, WA 98195 (United States); Shen, Sijing; Wadsley, James, E-mail: az481@nyu.ed, E-mail: bwillman@haverford.ed [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L88 4M1 (Canada)

    2010-09-20

    Fully cosmological, high-resolution N-body+smooth particle hydrodynamic simulations are used to investigate the chemical abundance trends of stars in simulated stellar halos as a function of their origin. These simulations employ a physically motivated supernova feedback recipe, as well as metal enrichment, metal cooling, and metal diffusion. As presented in an earlier paper, the simulated galaxies in this study are surrounded by stellar halos whose inner regions contain both stars accreted from satellite galaxies and stars formed in situ in the central regions of the main galaxies and later displaced by mergers into their inner halos. The abundance patterns ([Fe/H] and [O/Fe]) of halo stars located within 10 kpc of a solar-like observer are analyzed. We find that for galaxies which have not experienced a recent major merger, in situ stars at the high [Fe/H] end of the metallicity distribution function are more [{alpha}/Fe]-rich than accreted stars at similar [Fe/H]. This dichotomy in the [O/Fe] of halo stars at a given [Fe/H] results from the different potential wells within which in situ and accreted halo stars form. These results qualitatively match recent observations of local Milky Way halo stars. It may thus be possible for observers to uncover the relative contribution of different physical processes to the formation of stellar halos by observing such trends in the halo populations of the Milky Way and other local L{sup *} galaxies.

  11. Conformastationary disk-haloes in Einstein-Maxwell gravity

    E-Print Network [OSTI]

    Antonio C. Gutiérrez-Piñeres

    2015-04-14

    An exact solution of the Einstein-Maxwell field equations for a conformastationary metric with magnetized disk-haloes sources is worked out in full. The characterization of the nature of the energy momentum tensor of the source is discussed. All the expressions are presented in terms of a solution of the Laplace's equation. A "generalization" of the Kuzmin solution of the Laplace's equations is used as a particular example. The solution obtained is asymptotically flat in general and turns out to be free of singularities. All the relevant quantities show a reasonable physical behaviour.

  12. Neutron-Neutron Correlations in the Dissociation of Halo Nuclei

    E-Print Network [OSTI]

    N. A. Orr

    2008-03-06

    Studies attempting to probe the spatial configuration of the valence neutrons in two-neutron halo nuclei using the technique of intensity interferometry are described. Following a brief review of the method and its application to earlier measurements of the breakup of 6He, 11Li and 14Be, the results of the analysis of a high statistics data set for 6He are presented. The limitations of the technique, including the assumption of incoherent emission in the breakup and the sensitivity to the continuum states populated in the dissociation rather than the ground state, are discussed.

  13. Core excitation effects in the breakup of halo nuclei

    SciTech Connect (OSTI)

    Moro, A. M.; Diego, R. de; Lay, J. A.; Crespo, R.; Johnson, R. C.; Arias, J. M.; Gomez-Camacho, J.

    2012-10-20

    The role of core excitation in the structure and dynamics of two-body halo nuclei is investigated. We present calculations for the resonant breakup of {sup 11}Be on protons at an incident energy of 63.7 MeV/nucleon, where core excitation effects were shown to be important. To describe the reaction, we use a recently developed extension of the DWBA formalism which incorporates these core excitation effects within the no-recoil approximation. The validity of the no-recoil approximation is also examined by comparing with DWBA calculations which take into account core recoil. In addition, calculations with two different continuum representations are presented and compared.

  14. Halo formation and self-pinching of an electron beam undergoing the Weibel instability

    E-Print Network [OSTI]

    Kaganovich, Igor

    Halo formation and self-pinching of an electron beam undergoing the Weibel instability Vladimir-D Phys. Plasmas 19, 092511 (2012) 0.22 THz wideband sheet electron beam traveling wave tube amplifier://pop.aip.org/about/rights_and_permissions #12;Halo formation and self-pinching of an electron beam undergoing the Weibel instability Vladimir

  15. Effects of Merging Histories on Angular Momentum Distribution of Dark Matter Haloes

    E-Print Network [OSTI]

    Masahiro Nagashima; Naoteru Gouda

    1998-09-29

    The effects of merging histories of proto-objects on the angular momentum distributions of the present-time dark matter haloes are analysed. An analytical approach to the analysis of the angular momentum distributions assumes that the haloes are initially homogeneous ellipsoids and that the growth of the angular momentum of the haloes halts at their maximum expansion time. However, the maximum expansion time cannot be determined uniquely, because in the hierarchical clustering scenario each progenitor, or subunit, of the halo has its own maximum expansion time. Therefore the merging history of the halo may be important in estimating its angular momentum. Using the merger tree model by Rodrigues & Thomas, which takes into account the spatial correlations of the density fluctuations, we have investigated the effects of the merging histories on the angular momentum distributions of dark matter haloes. It was found that the merger effects, that is, the effects of the inhomogeneity of the maximum expansion times of the progenitors which finally merge together into a halo, do not strongly affect the final angular momentum distributions, so that the homogeneous ellipsoid approximation happens to be good for the estimation of the angular momentum distribution of dark matter haloes. This is because the effect of the different directions of the angular momenta of the progenitors cancels out the effect of the inhomogeneity of the maximum expansion times of the progenitors.

  16. DYNAMICS OF A SOLAR SAIL NEAR A HALO ORBIT A. Farresa,

    E-Print Network [OSTI]

    Barcelona, Universitat de

    DYNAMICS OF A SOLAR SAIL NEAR A HALO ORBIT A. Farr´esa, , `A. Jorbaa a Departament de Matem Abstract In this work we are interested in the local dynamics around a Halo - type orbit for a solar sail and how it varies when the sail orientation changes. To model the dynamics of a solar sail we have

  17. A new look at microlensing limits on dark matter in the Galactic halo

    E-Print Network [OSTI]

    Hawkins, M R S

    2015-01-01

    The motivation for this paper is to review the limits set on the MACHO content of the Galactic halo by microlensing experiments in the direction of the Large Magellanic Cloud. This has been prompted by recent measurements of the Galactic rotation curve, which suggest that the limits have been biassed by the assumption of an over-massive halo. The paper first discusses the security of the detection efficiency calculations which are central to deriving the MACHO content of the Galactic halo. It then sets out to compare the rotation curves from various halo models with recent observations, with a view to establishing what limits can be put on an all-MACHO halo. The main thrust of the paper is to investigate whether lighter halo models which are consistent with microlensing by an all-MACHO halo are also consistent with recent measures of the Galactic rotation curve. In this case the population of bodies discovered by the MACHO collaboration would make up the entire dark matter content of the Galactic halo. The ma...

  18. Abundance Signatures in Halo Stars: Clues to Nucleosynthesis in the First Stars

    E-Print Network [OSTI]

    Cowan, John

    Abundance Signatures in Halo Stars: Clues to Nucleosynthesis in the First Stars John J. Cowan-based telescopes to make extensive studies of Galactic halo stars. These stars contain the nucleosynthesis products the earliest Galactic r-process nucleosynthesis. These in turn will help to identify the characteristics

  19. The distribution function of the Galaxy's dark halo

    E-Print Network [OSTI]

    Binney, James

    2015-01-01

    Starting from the hypothesis that the Galaxy's dark halo responded adiabatically to the infall of baryons, we have constructed a self-consistent dynamical model of the Galaxy that satisfies a large number of observations, including measurements of gas terminal velocities and masers, the kinematics of a 180,000 giant stars from the RAVE survey, and star count data from the SDSS. The stellar disc and the dark halo are both specified by distribution functions (DFs) of the action integrals. The model is obtained by extending the work of Piffl Penoyre & Binney (2015} from the construction of a single model to a systematic search of model space. Whereas the model of Piffl et al violated constraints on the terminal-velocity curve, our model respects these constraints by adopting a long scale length R_d=3.66 kpc for the thin and thick discs. The model is, however, inconsistent with the measured optical depth for microlensing of bulge stars because it attributes too large a fraction of the density at R <~ 3 kpc...

  20. THE SPIN AND ORIENTATION OF DARK MATTER HALOS WITHIN COSMIC FILAMENTS

    SciTech Connect (OSTI)

    Zhang Youcai; Yang Xiaohu; Lin Weipeng; Faltenbacher, Andreas; Springel, Volker; Wang Huiyuan

    2009-11-20

    Clusters, filaments, sheets, and voids are the building blocks of the cosmic web. Forming dark matter halos respond to these different large-scale environments, and this in turn affects the properties of galaxies hosted by the halos. It is therefore important to understand the systematic correlations of halo properties with the morphology of the cosmic web, as this informs both about galaxy formation physics and possible systematics of weak lensing studies. In this study, we present and compare two distinct algorithms for finding cosmic filaments and sheets, a task which is far less well established than the identification of dark matter halos or voids. One method is based on the smoothed dark matter density field and the other uses the halo distributions directly. We apply both techniques to one high-resolution N-body simulation and reconstruct the filamentary/sheet like network of the dark matter density field. We focus on investigating the properties of the dark matter halos inside these structures, in particular, on the directions of their spins and the orientation of their shapes with respect to the directions of the filaments and sheets. We find that both the spin and the major axes of filament halos with masses approx<10{sup 13} h {sup -1} M{sub sun} are preferentially aligned with the direction of the filaments. The spins and major axes of halos in sheets tend to lie parallel to the sheets. There is an opposite mass dependence of the alignment strength for the spin (negative) and major (positive) axes, i.e. with increasing halo mass the major axis tends to be more strongly aligned with the direction of the filament, whereas the alignment between halo spin and filament becomes weaker with increasing halo mass. The alignment strength as a function of the distance to the most massive node halo indicates that there is a transit large-scale environment impact: from the two-dimensional collapse phase of the filament to the three-dimensional collapse phase of the cluster/node halo at small separation. Overall, the two algorithms for filament/sheet identification investigated here agree well with each other. The method based on halos alone can be easily adapted for use with observational data sets.

  1. Space Weather Application Using Projected Velocity Asymmetry of Halo CMEs

    E-Print Network [OSTI]

    G. Michalek; N. Gopalswamy; S. Yashiro

    2008-01-13

    Halo coronal mass ejections (HCMEs) originating from regions close to the center of the Sun are likely to be responsible for severe geomagnetic storms. It is important to predict geo-effectiveness of HCMEs using observations when they are still near the Sun. Unfortunately, coronagraphic observations do not provide true speeds of CMEs due to the projection effects. In the present paper, we present a new technique allowing estimate the space speed and approximate source location using projected speeds measured at different position angles for a given HCME (velocity asymmetry). We apply this technique to HCMEs observed during 2001-2002 and find that the improved speeds are better correlated with the travel times of HCMEs to Earth and with the magnitudes ensuing geomagnetic storms.

  2. Electromagnetic properties of the Be-11 nucleus in Halo EFT

    E-Print Network [OSTI]

    D. R. Phillips; H. -W. Hammer

    2010-01-19

    We compute electromagnetic properties of the Be-11 nucleus using an effective field theory that exploits the separation of scales in this halo system. We fix the parameters of the EFT from measured data on levels and scattering lengths in the Be-10 plus neutron system. We then obtain predictions for the B(E1) strength of the 1/2^+ to 1/2^- transition in the Be-11 nucleus. We also compute the charge radius of the ground state of Be-11. Agreement with experiment within the expected accuracy of a leading-order computation in this EFT is obtained. We also indicate how higher-order corrections that affect both s-wave and p-wave Be-10-neutron interactions will affect our results.

  3. Spectral Energy Distributions for Disk and Halo M--Dwarfs

    E-Print Network [OSTI]

    S. K. Leggett; F. Allard; Conard Dahn; P. H. Hauschildt; T. H. Kerr; J. Rayner

    2000-01-07

    We have obtained infrared (1 to 2.5 micron) spectroscopy for 42 halo and disk dwarfs with spectral type M1 to M6.5. These data are compared to synthetic spectra generated by the latest model atmospheres of Allard & Hauschildt. Photospheric parameters metallicity, effective temperature and radius are determined for the sample. We find good agreement between observation and theory except for known problems due to incomplete molecular data for metal hydrides and water. The metal-poor M subdwarfs are well matched by the models as oxide opacity sources are less important in this case. The derived effective temperatures for the sample range from 3600K to 2600K; at these temperatures grain formation and extinction are not significant in the photosphere. The derived metallicities range from solar to one-tenth solar. The radii and effective temperatures derived agree well with recent models of low mass stars.

  4. The importance of the cosmic web and halo substructure for power spectra

    E-Print Network [OSTI]

    Pace, Francesco; Bacon, David J; Crittenden, Robert; Percival, Will J

    2015-01-01

    In this work we study the relevance of the cosmic web and substructures on the matter and lensing power spectra measured from halo mock catalogues extracted from the N-body simulations. Since N-body simulations are computationally expensive, it is common to use faster methods that approximate the dark matter field as a set of halos. In this approximation, we replace mass concentrations in N-body simulations by a spherically symmetric Navarro-Frenk-White halo density profile. We also consider the full mass field as the sum of two distinct fields: dark matter halos ($M>9\\times 10^{12}~M_{\\odot}$/h) and particles not included into halos. Mock halos reproduce well the matter power spectrum, but underestimate the lensing power spectrum on large and small scales. For sources at $z_{\\rm s}=1$ the lensing power spectrum is underestimated by up to 40% at $\\ell\\approx 10^4$ with respect to the simulated halos. The large scale effect can be alleviated by combining the mock catalogue with the dark matter distribution out...

  5. THE STELLAR-TO-HALO MASS RELATION FOR LOCAL GROUP GALAXIES

    SciTech Connect (OSTI)

    Brook, C. B.; Cintio, A. Di; Knebe, A.; Yepes, G.; Gottlöber, S.; Hoffman, Y.; Garrison-Kimmel, S.

    2014-03-20

    We contend that a single power-law halo mass distribution is appropriate for direct matching to the stellar masses of observed Local Group dwarf galaxies, allowing the determination of the slope of the stellar mass-halo mass relation for low-mass galaxies. Errors in halo masses are well defined as the Poisson noise of simulated Local Group realizations, which we determine using local volume simulations. For the stellar mass range 10{sup 7} M {sub ?}halo mass relation follows a power law with slope of 3.1, significantly steeper than most values in the literature. This steep relation between stellar and halo masses would indicate that Local Group dwarf galaxies are hosted by dark matter halos with a small range of mass. Our methodology is robust down to the stellar mass to which the census of observed Local Group galaxies is complete, but the significant uncertainty in the currently measured slope of the stellar-to-halo mass relation will decrease dramatically if the Local Group completeness limit was 10{sup 6.5} M {sub ?} or below, highlighting the importance of pushing such limit to lower masses and larger volumes.

  6. Electromagnetic form factors of one neutron halos with spin 1/2+ ground state

    E-Print Network [OSTI]

    Fernando, Lakma; Rupak, Gautam

    2015-01-01

    The electromagnetic form factors for single neutron halo nuclei Be-11, C-15 and C-19 are calculated. The calculations are performed in halo effective field theory (EFT) where the halo nuclei are approximated as made of a single neutron and a core. The form factors depend on the single neutron separation energy, the s-wave neutron-core scattering effective range and a two-body current. The EFT expressions are presented to leading order for C-15 and next-to-leading order for Be-11 and C-19.

  7. Possible features of galactic halo with electric field and observational constraints

    E-Print Network [OSTI]

    Koushik Chakraborty; Farook Rahaman; Saibal Ray; Arka Nandi; Nasarul Islam

    2014-12-15

    Observed rotational curves of neutral hydrogen clouds strongly support the fact that galactic halo contains huge amount of nonluminous matter, the so called gravitational dark matter. The nature of dark matter is a point of debate among the researchers. Recent observations reported the presence of ions of O, S, C, Si etc in the galactic halo and intergalactic medium. This supports the possibility of existence of electric field in the galactic halo region. We therefore propose a model of galactic halo considering this electric field arising due to charged particles as one of the inputs for the background spacetime metric. Considering dark matter as an anisotropic fluid we obtain the expressions for energy density and pressure of dark matter there and consequently the equation of state of dark matter. Various other aspects of the solutions are also analyzed along with a critical comparison with and constraints of different observational evidences.

  8. X-ray scattered halo around IGR J17544–2619

    SciTech Connect (OSTI)

    Mao, Junjie; Ling, Zhixing; Zhang, Shuang-Nan, E-mail: zhangsn@ihep.ac.cn [National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

    2014-04-10

    X-ray photons coming from an X-ray point source not only arrive at the detector directly, but also can be strongly forward-scattered by the interstellar dust along the line of sight (LOS), leading to a detectable diffuse halo around the X-ray point source. The geometry of small-angle X-ray scattering is straightforward, namely, the scattered photons travel longer paths and thus arrive later than the unscattered ones; thus, the delay time of X-ray scattered halo photons can reveal information of the distances of the interstellar dust and the point source. Here we present a study of the X-ray scattered halo around IGR J17544–2619, which is one of the so-called supergiant fast X-ray transients. IGR J17544–2619 underwent a striking outburst when observed with Chandra on 2004 July 3, providing a near ?-function light curve. We find that the X-ray scattered halo around IGR J17544–2619 is produced by two interstellar dust clouds along the LOS. The one that is closer to the observer gives the X-ray scattered halo at larger observational angles, whereas the farther one, which is in the vicinity of the point source, explains the halo with a smaller angular size. By comparing the observational angle of the scattered halo photons with that predicted by different dust grain models, we are able to determine the normalized dust distance. With the delay times of the scattered halo photons, we can determine the point source distance, given a dust grain model. Alternatively, we can discriminate between the dust grain models, if the point source distance is known independently.

  9. The end of the MACHO era, revisited: New limits on MACHO masses from halo wide binaries

    SciTech Connect (OSTI)

    Monroy-Rodríguez, Miguel A.; Allen, Christine

    2014-08-01

    In order to determine an upper bound for the mass of the massive compact halo objects (MACHOs), we use the halo binaries contained in a recent catalog by Allen and Monroy-Rodríguez. To dynamically model their interactions with massive perturbers, a Monte Carlo simulation is conducted, using an impulsive approximation method and assuming a galactic halo constituted by massive particles of a characteristic mass. The results of such simulations are compared with several subsamples of our improved catalog of candidate halo wide binaries. In accordance with Quinn et al., we also find our results to be very sensitive to the widest binaries. However, our larger sample, together with the fact that we can obtain galactic orbits for 150 of our systems, allows a more reliable estimate of the maximum MACHO mass than that obtained previously. If we employ the entire sample of 211 candidate halo stars we, obtain an upper limit of 112 M{sub ?}. However, using the 150 binaries in our catalog with computed galactic orbits, we are able to refine our fitting criteria. Thus, for the 100 most halo-like binaries we obtain a maximum MACHO mass of 21-68 M{sub ?}. Furthermore, we can estimate the dynamical effects of the galactic disk using binary samples that spend progressively shorter times within the disk. By extrapolating the limits obtained for our most reliable—albeit smallest—sample, we find that as the time spent within the disk tends to zero, the upper bound of the MACHO mass tends to less than 5 M{sub ?}. The non-uniform density of the halo has also been taken into account, but the limit obtained, less than 5 M{sub ?}, does not differ much from the previous one. Together with microlensing studies that provide lower limits on the MACHO mass, our results essentially exclude the existence of such objects in the galactic halo.

  10. Non-local bias in the halo bispectrum with primordial non-Gaussianity

    E-Print Network [OSTI]

    Matteo Tellarini; Ashley J. Ross; Gianmassimo Tasinato; David Wands

    2015-06-10

    Primordial non-Gaussianity can lead to a scale-dependent bias in the density of collapsed halos relative to the underlying matter density. The galaxy power spectrum already provides constraints on local-type primordial non-Gaussianity complementary those from the cosmic microwave background (CMB), while the bispectrum contains additional shape information and has the potential to outperform CMB constraints in future. We develop the bias model for the halo density contrast in the presence of local-type primordial non-Gaussianity, deriving a bivariate expansion up to second order in terms of the local linear matter density contrast and the local gravitational potential in Lagrangian coordinates. Non-linear evolution of the matter density introduces a non-local tidal term in the halo model. Furthermore, the presence of local-type non-Gaussianity in the Lagrangian frame leads to a novel non-local convective term in the Eulerian frame, that is proportional to the displacement field when going beyond the spherical collapse approximation. We use an extended Press-Schechter approach to evaluate the halo mass function and thus the halo bispectrum. We show that including these non-local terms in the halo bispectra can lead to corrections of up to $25\\%$ for some configurations, on large scales or at high redshift.

  11. Spin Flips - II. Evolution of dark matter halo spin orientation, and its correlation with major mergers

    E-Print Network [OSTI]

    Bett, Philip E

    2015-01-01

    We expand our previous study on the relationship between changes in the orientation of the angular momentum vector of dark matter haloes ("spin flips") and changes in their mass (Bett & Frenk 2012), to cover the full range of halo masses in a simulation cube of length 100 $h^{-1}$ Mpc. Since strong disturbances to a halo (such as might be indicated by a large change in the spin direction) are likely also to disturb the galaxy evolving within, spin flips could be a mechanism for galaxy morphological transformation without involving major mergers. We find that 35% of haloes have, at some point in their lifetimes, had a spin flip of at least $45\\deg$ that does not coincide with a major merger. Over 75% of large spin flips coincide with non-major mergers; only a quarter coincide with major mergers. We find a similar picture for changes to the inner-halo spin orientation, although here there is an increased likelihood of a flip occurring. Changes in halo angular momentum orientation, and other such measures of...

  12. Shape profiles and orientation bias for weak and strong lensing cluster halos

    SciTech Connect (OSTI)

    Groener, A. M.; Goldberg, D. M.

    2014-11-10

    We study the intrinsic shape and alignment of isodensities of galaxy cluster halos extracted from the MultiDark MDR1 cosmological simulation. We find that the simulated halos are extremely prolate on small scales and increasingly spherical on larger ones. Due to this trend, analytical projection along the line of sight produces an overestimation of the concentration index as a decreasing function of radius, which we quantify by using both the intrinsic distribution of three-dimensional concentrations (c {sub 200}) and isodensity shape on weak and strong lensing scales. We find this difference to be ?18% (?9%) for low- (medium-)mass cluster halos with intrinsically low concentrations (c {sub 200} = 1-3), while we find virtually no difference for halos with intrinsically high concentrations. Isodensities are found to be fairly well aligned throughout the entirety of the radial scale of each halo population. However, major axes of individual halos have been found to deviate by as much as ?30°. We also present a value-added catalog of our analysis results, which we have made publicly available to download.

  13. The MassiveBlack-II simulation: The evolution of haloes and galaxies to z ~ 0

    SciTech Connect (OSTI)

    Khandai, Nishikanta; Di Matteo, Tiziana; Croft, Rupert; Wilkins, Stephen; Feng, Yu; Tucker, Evan; DeGraf, Colin; Liu, Mao -Sheng

    2015-04-24

    We investigate the properties and clustering of halos, galaxies and blackholes to z = 0 in the high resolution hydrodynamical simulation MassiveBlack-II (MBII). MBII evolves a ?CDM cosmology in a cubical comoving volume Vbox = (100Mpc/h)³. It is the highest resolution simulation of this size which includes a self-consistent model for star formation, black hole accretion and associated feedback. We provide a simulation browser web application which enables interactive search and tagging of the halos, subhalos and their properties and publicly release our galaxy catalogs to the scientific community. Our analysis of the halo mass function in MBII reveals that baryons have strong effects with changes in the halo abundance of 20–35% below the knee of the mass function (Mhalo 1013.2 M? h at z = 0) when compared to dark-matter-only simulations. We provide a fitting function for the halo MF out to redshift z = 11 and discuss its limitations.

  14. Linking the Metallicity Distribution of Galactic Halo Stars to the Enrichment History of the Universe

    E-Print Network [OSTI]

    Evan Scannapieco; Tom Broadhurst

    2001-02-06

    We compare the metallicity distribution of Galactic Halo stars with 3D realizations of hierarchical galaxy formation. Outflows from dwarf galaxies enrich the intergalactic medium inhomogeneously, at a rate depending on the local galaxy density. Consequently, the first stars created in small early-forming galaxies are less metal-rich that the first stars formed in more massive galaxies which typically form later. As most halo stars are likely to originate in accreted dwarfs, while disk stars formed out of outflow-enriched gas, this scenario naturally generates a ``metallicity floor'' for old disk stars, which we find to be roughly coincident with the higher end of our predicted metallicity distribution of halo stars, in agreement with observations. The broad and centrally peaked distribution of halo star metallicities is well reproduced in our models, with a natural dispersion depending on the exact accretion history. Our modeling includes the important ``baryonic stripping'' effect of early outflows, which brush away the tenuously held gas in neighboring pre-virialized density perturbations. This stripping process does not significantly modify the predicted shape of the halo star metal distribution but inhibits star-formation and hence the number of accreted stars, helping to reproduce the observed total Galactic halo luminosity and also the lack of low-luminosity local dwarf galaxies relative to N-body predictions.

  15. A DISTANT RADIO MINI-HALO IN THE PHOENIX GALAXY CLUSTER

    SciTech Connect (OSTI)

    Van Weeren, R. J.; Andrade-Santos, F.; Forman, W. R.; Jones, C. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Intema, H. T. [National Radio Astronomy Observatory, 1003 Lopezville Road, Socorro, NM 87801-0387 (United States); Lal, D. V. [National Centre for Radio Astrophysics, TIFR, Pune University Campus, Post Bag 3, Pune 411 007 (India); Brüggen, M.; De Gasperin, F. [Hamburger Sternwarte, Gojenbergsweg 112, D-21029 Hamburg (Germany); Hoeft, M. [Thüringer Landessternwarte Tautenburg, Sternwarte 5, D-07778, Tautenburg (Germany); Nuza, S. E. [Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany); Röttgering, H. J. A.; Stroe, A., E-mail: rvanweeren@cfa.harvard.edu [Leiden Observatory, Leiden University, P.O. Box 9513, NL-2300 RA Leiden (Netherlands)

    2014-05-10

    We report the discovery of extended radio emission in the Phoenix cluster (SPT-CL J2344-4243, z = 0.596) with the Giant Metrewave Radio Telescope (GMRT) at 610 MHz. The diffuse emission extends over a region of at least 400-500 kpc and surrounds the central radio source of the Brightest Cluster Galaxy, but does not appear to be directly associated with it. We classify the diffuse emission as a radio mini-halo, making it the currently most distant mini-halo known. Radio mini-halos have been explained by synchrotron emitting particles re-accelerated via turbulence, possibly induced by gas sloshing generated from a minor merger event. Chandra observations show a non-concentric X-ray surface brightness distribution, which is consistent with this sloshing interpretation. The mini-halo has a flux density of 17 ± 5 mJy, resulting in a 1.4 GHz radio power of (10.4 ± 3.5) × 10{sup 24} W Hz{sup –1}. The combined cluster emission, which includes the central compact radio source, is also detected in a shallow GMRT 156 MHz observation and together with the 610 MHz data we compute a spectral index of –0.84 ± 0.12 for the overall cluster radio emission. Given that mini-halos typically have steeper radio spectra than cluster radio galaxies, this spectral index should be taken as an upper limit for the mini-halo.

  16. Beyond the Bulge: a Fundamental Relation Between Supermassive Black Holes and Dark Matter Halos

    E-Print Network [OSTI]

    Laura Ferrarese

    2002-07-01

    The possibility that the masses of supermassive black holes (SBHs) correlate with the total gravitational mass of their host galaxy, or the mass of the dark matter halo in which they presumably formed, is investigated using a sample of 16 spiral and 20 elliptical galaxies. The bulge velocity dispersion, typically defined within an aperture of size less than 0.5 kpc, is found to correlate tightly with the galaxy's circular velocity, the latter measured at distances from the galactic center at which the rotation curve is flat, 20 to 80kpc. By using the well known M-sigma relation for SBHs, and a prescription to relate the circular velocity to the mass of the dark matter halo in a standard CDM cosmology, the correlation between velocity dispersion and circular velocity is equivalent to one between SBH and halo masses. Such a correlation is found to be nonlinear, with the ratio between the two masses decreasing from 2X10^-4 for halos of 10^14 solar masses, to 10^-5 for halos of 10^12 solar masses. Preliminary evidence suggests that halos smaller than ~5X10^11 solar masses are increasingly less efficient -- perhaps unable -- at forming SBHs.

  17. Spectral Energy Distributions for Disk and Halo M Dwarfs

    SciTech Connect (OSTI)

    Leggett, S. K.; Allard, F.; Dahn, Conard; Hauschildt, P. H.; Kerr, T. H.; Rayner, J.

    2000-06-01

    We have obtained infrared (1-2.5 {mu}m) spectroscopy for 42 halo and disk dwarfs with spectral types M1-M6.5. These data are compared to synthetic spectra generated by the latest model atmospheres of Allard and Hauschildt. Photospheric parameters metallicity, effective temperature, and radius are determined for the sample.We find good agreement between observation and theory except for known problems due to incomplete molecular data for metal hydrides and H2O. The metal-poor M subdwarfs are well matched by the models, as oxide opacity sources are less important in this case. The derived effective temperatures for the sample range from 3600 to 2600 K; at these temperatures grain formation and extinction are not significant in the photosphere. The derived metallicities range from solar to 1/10 solar. The radii and effective temperatures derived agree well with recent models of low-mass stars. The spectra are available in electronic form upon request. (c) 2000 The American Astronomical Society.

  18. Column Density Profiles of Multi-Phase Gaseous Halos

    E-Print Network [OSTI]

    Liang, Cameron J; Agertz, Oscar

    2015-01-01

    We present a suite of high-resolution cosmological galaxy re-simulations of a Milky-Way size halo with variety of star-formation and feedback models to investigate the effects of the specific details of the star formation-feedback loop modeling on the observable properties of the circumgalactic medium (CGM). We show that properties of the CGM are quite sensitive to the details of star formation-feedback loop. The simulation which produces a very realistic late-type central galaxy fails to reproduce existing observations of CGM. At the same time, variations of parameters of star formation recipe or feedback modeling, such as cosmic rays feedback, brings predicted CGM in better agreement with observations. The simulations show that the column density profiles of ions arising in such gas are well described by an exponential function of the impact parameter. Ions with higher ionization energy have more extended profiles with the scale height of the exponential distribution scaling as a power law of the ionization...

  19. Gamma-rays from halos around stars and the Sun

    E-Print Network [OSTI]

    Elena Orlando; Andrew Strong

    2006-10-31

    Inverse Compton scattering by relativistic electrons produces a major component of the diffuse emission from the Galaxy. The photon fields involved are the cosmic microwave background and the interstellar radiation field from stars and dust. Calculations of the inverse Compton distribution have usually assumed a smooth ISRF, but in fact a large part of the Galactic luminosity comes from the most luminous stars which are rare. Therefore we expect the ISRF, and hence the inverse Compton emission, to be clumpy at some level which could be detectable by instruments such as GLAST. Even individual nearby luminous stars could be detectable assuming just the normal cosmic-ray electron spectrum. We present the basic formalism required and give possible candidate stars to be detected, and make predictions for GLAST. Then we apply the formalism to OB associations and the Sun, showing that the IC emission produced is not negligible compared to the sensitivity of current or coming detectors. We estimate that the gamma-ray flux from the halo around the Sun contributes to the diffuse background emission at about the few percent level.

  20. Mass segregation in the outer halo globular cluster Palomar 14

    E-Print Network [OSTI]

    Frank, Matthias J; Kuepper, Andreas H W

    2014-01-01

    We present evidence for mass segregation in the outer-halo globular cluster Palomar 14, which is intuitively unexpected since its present-day two-body relaxation time significantly exceeds the Hubble time. Based on archival Hubble Space Telescope imaging, we analyze the radial dependence of the stellar mass function in the cluster's inner 39.2 pc in the mass range of 0.53-0.80 M_sun, ranging from the main-sequence turn-off down to a V-band magnitude of 27.1 mag. The mass function at different radii is well approximated by a power law and rises from a shallow slope of 0.6+/-0.2 in the cluster's core to a slope of 1.6+/-0.3 beyond 18.6 pc. This is seemingly in conflict with the finding by Beccari et al. (2011), who interpret the cluster's non-segregated population of (more massive) blue straggler stars, compared to (less massive) red giants and horizontal branch stars, as evidence that the cluster has not experienced dynamical segregation yet. We discuss how both results can be reconciled. Our findings indicate...

  1. Electric properties of the Beryllium-11 system in Halo EFT

    E-Print Network [OSTI]

    H. -W. Hammer; D. R. Phillips

    2012-08-15

    We compute E1 transitions and electric radii in the Beryllium-11 nucleus using an effective field theory that exploits the separation of scales in this halo system. We fix the leading-order parameters of the EFT from measured data on the 1/2+ and 1/2- levels in Be-11 and the B(E1) strength for the transition between them. We then obtain predictions for the B(E1) strength for Coulomb dissociation of the Be-11 nucleus to the continuum. We also compute the charge radii of the 1/2+ and 1/2- states. Agreement with experiment within the expected accuracy of a leading-order computation in this EFT is obtained. We also discuss how next-to-leading-order (NLO) corrections involving both s-wave and p-wave neutron-Be-10 interactions affect our results, and display the NLO predictions for quantities which are free of additional short-distance operators at this order. Information on neutron-Be-10 scattering in the relevant channels is inferred.

  2. Coulomb effects on the formation of proton halo nuclei

    E-Print Network [OSTI]

    Yu-Jie Liang; Yan-Song Li; Fu-Guo Deng; Xi-Han Li; Bao-An Bian; Feng-Shou Zhang; Zu-Hua Liu; Hong-Yu Zhou

    2007-08-01

    The exotic structures in the 2s_{1/2} states of five pairs of mirror nuclei ^{17}O-^{17}F, ^{26}Na-^{26}P, ^{27}Mg-^{27}P, ^{28}Al-^{28}P and ^{29}Si-^{29}P are investigated with the relativistic mean-field (RMF) theory and the single-particle model (SPM) to explore the role of the Coulomb effects on the proton halo formation. The present RMF calculations show that the exotic structure of the valence proton is more obvious than that of the valence neutron of its mirror nucleus, the difference of exotic size between each mirror nuclei becomes smaller with the increase of mass number A of the mirror nuclei and the ratios of the valence proton and valence neutron root-mean-square (RMS) radius to the matter radius in each pair of mirror nuclei all decrease linearly with the increase of A. In order to interpret these results, we analyze two opposite effects of Coulomb interaction on the exotic structure formation with SPM and find that the contribution of the energy level shift is more important than that of the Coulomb barrier for light nuclei. However, the hindrance of the Coulomb barrier becomes more obvious with the increase of A. When A is larger than 34, Coulomb effects on the exotic structure formation will almost become zero because its two effects counteract with each other.

  3. Disk Contamination in a sample of proper motion selected halo stars: A Comment on "Direct Detection of Galactic Halo Dark Matter", B.A. Oppenheimer et al., Science

    E-Print Network [OSTI]

    David S. Graff

    2001-07-12

    Based on a proper motion survey, Oppenheimer et al. claim the detection of a white dwarf component of the dark matter of the halo. I show that most of the white dwarfs in their sample are likely disk white dwarfs which have been previously detected, and represent no new population.

  4. ACCURATE UNIVERSAL MODELS FOR THE MASS ACCRETION HISTORIES AND CONCENTRATIONS OF DARK MATTER HALOS

    SciTech Connect (OSTI)

    Zhao, D. H.; Jing, Y. P.; Mo, H. J.; Boerner, G.

    2009-12-10

    A large amount of observations have constrained cosmological parameters and the initial density fluctuation spectrum to a very high accuracy. However, cosmological parameters change with time and the power index of the power spectrum dramatically varies with mass scale in the so-called concordance LAMBDACDM cosmology. Thus, any successful model for its structural evolution should work well simultaneously for various cosmological models and different power spectra. We use a large set of high-resolution N-body simulations of a variety of structure formation models (scale-free, standard CDM, open CDM, and LAMBDACDM) to study the mass accretion histories, the mass and redshift dependence of concentrations, and the concentration evolution histories of dark matter halos. We find that there is significant disagreement between the much-used empirical models in the literature and our simulations. Based on our simulation results, we find that the mass accretion rate of a halo is tightly correlated with a simple function of its mass, the redshift, parameters of the cosmology, and of the initial density fluctuation spectrum, which correctly disentangles the effects of all these factors and halo environments. We also find that the concentration of a halo is strongly correlated with the universe age when its progenitor on the mass accretion history first reaches 4% of its current mass. According to these correlations, we develop new empirical models for both the mass accretion histories and the concentration evolution histories of dark matter halos, and the latter can also be used to predict the mass and redshift dependence of halo concentrations. These models are accurate and universal: the same set of model parameters works well for different cosmological models and for halos of different masses at different redshifts, and in the LAMBDACDM case the model predictions match the simulation results very well even though halo mass is traced to about 0.0005 times the final mass, when cosmological parameters and the power index of the initial density fluctuation spectrum have changed dramatically. Our model predictions also match the PINOCCHIO mass accretion histories very well, which are much independent of our numerical simulations and our definitions of halo merger trees. These models are also simple and easy to implement, making them very useful in modeling the growth and structure of dark matter halos. We provide appendices describing the step-by-step implementation of our models. A calculator which allows one to interactively generate data for any given cosmological model is provided on the Web, together with a user-friendly code to make the relevant calculations and some tables listing the expected concentration as a function of halo mass and redshift in several popular cosmological models. We explain why LAMBDACDM and open CDM halos on nearly all mass scales show two distinct phases in their mass growth histories. We discuss implications of the universal relations we find in connection to the formation of dark matter halos in the cosmic density field.

  5. DOES THE SAGITTARIUS STREAM CONSTRAIN THE MILKY WAY HALO TO BE TRIAXIAL?

    SciTech Connect (OSTI)

    Ibata, R.; Martin, N. F.; Lewis, G. F.; Bellazzini, M.; Correnti, M.

    2013-03-01

    Recent analyses of the stellar stream of the Sagittarius dwarf galaxy have suggested that the kinematics and three-dimensional location of the M-giant stars in this structure constrain the dark matter halo of our Galaxy to possess a triaxial shape that is extremely flattened, being essentially an oblate ellipsoid oriented perpendicular to the Galactic disk. Using a new stream-fitting algorithm, based on a Markov Chain Monte Carlo procedure, we investigate whether this claim remains valid if we allow the density profile of the Milky Way halo greater freedom. We find stream solutions that fit the leading and trailing arms of this structure even in a spherical halo, although this would need a rising Galactic rotation curve at large Galactocentric radius. However, the required rotation curve is not ruled out by current constraints. It appears therefore that for the Milky Way, halo triaxiality, despite its strong theoretical motivation, is not required to explain the Sagittarius stream. This degeneracy between triaxiality and the halo density profile suggests that, in future endeavors to model this structure, it will be advantageous to relax the strict analytic density profiles that have been used to date.

  6. Taking Halo-Independent Dark Matter Methods Out of the Bin

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

    Fox, Patrick J.; Kahn, Yonatan; McCullough, Matthew

    2014-10-30

    We develop a new halo-independent strategy for analyzing emerging DM hints, utilizing the method of extended maximum likelihood. This approach does not require the binning of events, making it uniquely suited to the analysis of emerging DM direct detection hints. It determines a preferred envelope, at a given confidence level, for the DM velocity integral which best fits the data using all available information and can be used even in the case of a single anomalous scattering event. All of the halo-independent information from a direct detection result may then be presented in a single plot, allowing simple comparisons betweenmore »multiple experiments. This results in the halo-independent analogue of the usual mass and cross-section plots found in typical direct detection analyses, where limit curves may be compared with best-fit regions in halo-space. The method is straightforward to implement, using already-established techniques, and its utility is demonstrated through the first unbinned halo-independent comparison of the three anomalous events observed in the CDMS-Si detector with recent limits from the LUX experiment.« less

  7. The response of dark matter haloes to elliptical galaxy formation: a new test for quenching scenarios

    E-Print Network [OSTI]

    Dutton, Aaron A; Stinson, Gregory S; Gutcke, Thales A; Penzo, Camilla; Buck, Tobias

    2015-01-01

    We use cosmological hydrodynamical zoom-in simulations with the SPH code gasoline of four haloes of mass M_{200} \\sim 10^{13}\\Msun to study the response of the dark matter to elliptical galaxy formation. At z=2 the progenitor galaxies have stellar to halo mass ratios consistent with halo abundance matching, assuming a Salpeter initial mass function. However by z=0 the standard runs suffer from the well known overcooling problem, overpredicting the stellar masses by a factor of > 4. To mimic a suppressive halo quenching scenario, in our forced quenching (FQ) simulations, cooling and star formation are switched off at z=2. The resulting z=0 galaxies have stellar masses, sizes and circular velocities close to what is observed. Relative to the control simulations, the dark matter haloes in the FQ simulations have contracted, with central dark matter density slopes d\\log\\rho/d\\log r \\sim -1.5, showing that dry merging alone is unable to fully reverse the contraction that occurs at z>2. Simulations in the literatur...

  8. Techniques for the measurement of disruption halo currents in the National Spherical Torus Experiment

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

    Gerhardt, S. P.; Fredrickson, E.; Guttadora, L.; Kaita, R.; Kugel, H.; Menard, J.; Takahashi, H.

    2011-10-06

    This paper describes techniques for measuring halo currents, and their associated toroidal peaking, in the National Spherical Torus Experiments. The measurements are based on three techniques: (i) measurement of the toroidal field created by the poloidal halo current, either with segmented Rogowski coils or discrete toroidal field sensors, (ii) the direct measurement of halo currents into specially instrument tiles, and (iii) small Rogowski coils placed on the mechanical supports of in-vessel components. For the segmented Rogowski coils and discrete toroidal field detectors, it is shown that the toroidal peaking factor inferred from the data is significantly less than the peakingmore »factor of the underlying halo current distribution, and a simple model is developed to relate the two. For the array of discrete toroidal field detectors and small Rogowski sensors, the compensation steps that are used to isolate the halo current signal are described. The electrical and mechanical design of compact under-tile resistive shunts and mini-Rogowski coils is described. Example data from the various systems is shown.« less

  9. Techniques for the measurement of disruption halo currents in the National Spherical Torus Experiment

    SciTech Connect (OSTI)

    Gerhardt, S. P.; Fredrickson, E.; Guttadora, L.; Kaita, R.; Kugel, H.; Menard, J. [Princeton Plasma Physics Laboratory, Plainsboro, New Jersey 08540 (United States); Takahashi, H. [Princeton Fusion Research LLC, Princeton, New Jersey 08540 (United States)

    2011-10-15

    This paper describes techniques for measuring halo currents, and their associated toroidal peaking, in the National Spherical Torus Experiments [M. Ono et al., Nucl. Fusion 40, 557 (2000)]. The measurements are based on three techniques: (1) measurement of the toroidal field created by the poloidal halo current, either with segmented Rogowski coils or discrete toroidal field sensors, (2) the direct measurement of halo currents into specially instrument tiles, and (3) small Rogowski coils placed on the mechanical supports of in-vessel components. For the segmented Rogowski coils and discrete toroidal field detectors, it is shown that the toroidal peaking factor inferred from the data is significantly less than the peaking factor of the underlying halo current distribution, and a simple model is developed to relate the two. For the array of discrete toroidal field detectors and small Rogowski sensors, the compensation steps that are used to isolate the halo current signal are described. The electrical and mechanical design of compact under-tile resistive shunts and mini-Rogowski coils is described. Example data from the various systems are shown.

  10. The MassiveBlack-II simulation: The evolution of haloes and galaxies to z ~ 0

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

    Khandai, Nishikanta; Di Matteo, Tiziana; Croft, Rupert; Wilkins, Stephen; Feng, Yu; Tucker, Evan; DeGraf, Colin; Liu, Mao -Sheng

    2015-04-24

    We investigate the properties and clustering of halos, galaxies and blackholes to z = 0 in the high resolution hydrodynamical simulation MassiveBlack-II (MBII). MBII evolves a ?CDM cosmology in a cubical comoving volume Vbox = (100Mpc/h)³. It is the highest resolution simulation of this size which includes a self-consistent model for star formation, black hole accretion and associated feedback. We provide a simulation browser web application which enables interactive search and tagging of the halos, subhalos and their properties and publicly release our galaxy catalogs to the scientific community. Our analysis of the halo mass function in MBII reveals thatmore »baryons have strong effects with changes in the halo abundance of 20–35% below the knee of the mass function (Mhalo 1013.2 M? h at z = 0) when compared to dark-matter-only simulations. We provide a fitting function for the halo MF out to redshift z = 11 and discuss its limitations.« less

  11. Tetrahedral collapse: a rotational toy model of simultaneous dark-matter halo, filament and wall formation

    E-Print Network [OSTI]

    Neyrinck, Mark C

    2015-01-01

    We discuss an idealized model of halo formation, in which a collapsing halo node is tetrahedral, with a filament extruding from each of its four faces, and with a wall connecting each pair of filaments. In the model, filaments generally spin when they form, and the halo spins if and only if there is some rotation in filaments. This is the simplest-possible fully three-dimensional halo collapse in the 'origami approximation,' in which voids are irrotational, and the dark-matter sheet out of which dark-matter structures form is allowed to fold in position-velocity phase space, but not stretch (i.e., it cannot vary in density along a stream). Up to an overall scaling, the four filament directions, and only three other quantities, such as filament spins, suffice to determine all of the collapse's properties: the shape, mass, and spin of the halo; the densities per unit length and spins of all filaments; and masses per unit area of the walls. If the filaments are arranged regular-tetrahedrally, filament properties...

  12. Properties of Lithium-11 and Carbon-22 at leading order in halo effective field theory

    E-Print Network [OSTI]

    Acharya, Bijaya

    2015-01-01

    We study the $^{11}\\mathrm{Li}$ and $^{22}\\mathrm{C}$ nuclei at leading order (LO) in halo effective field theory (Halo EFT). Using the value of the $^{22}\\mathrm{C}$ rms matter radius deduced in Ref. [1] as an input in a LO calculation, we simultaneously constrained the values of the two-neutron (2$n$) separation energy of $^{22}\\mathrm{C}$ and the virtual-state energy of the $^{20}\\mathrm{C}-$neutron system (hereafter denoted $^{21}$C). The 1$-\\sigma$ uncertainty of the input rms matter radius datum, along with the theory error estimated from the anticipated size of the higher-order terms in the Halo EFT expansion, gave an upper bound of about 100 keV for the 2$n$ separation energy. We also study the electric dipole excitation of 2$n$ halo nuclei to a continuum state of two neutrons and the core at LO in Halo EFT. We first compare our results with the $^{11}\\mathrm{Li}$ data from a Coulomb dissociation experiment and obtain good agreement within the theoretical uncertainty of a LO calculation. We then obtai...

  13. An extended Zel'dovich model for the halo mass function

    SciTech Connect (OSTI)

    Lim, Seunghwan; Lee, Jounghun, E-mail: shlim@astro.snu.ac.kr, E-mail: jounghun@astro.snu.ac.kr [Astronomy Program, FPRD, Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of)

    2013-01-01

    A new way to construct a fitting formula for the halo mass function is presented. Our formula is expressed as a solution to the modified Jedamzik matrix equation that automatically satisfies the normalization constraint. The characteristic parameters expressed in terms of the linear shear eigenvalues are empirically determined by fitting the analytic formula to the numerical results from the high-resolution N-body simulation and found to be independent of scale, redshift and background cosmology. Our fitting formula with the best-fit parameters is shown to work excellently in the wide mass-range at various redshifts: The ratio of the analytic formula to the N-body results departs from unity by up to 10% and 5% over 10{sup 11} ? M/(h{sup ?1}M{sub s}un) ? 5 × 10{sup 15} at z = 0,0.5 and 1 for the FoF-halo and SO-halo cases, respectively.

  14. Possible signature of hypernova nucleosynthesis in a beryllium rich halo dwarf

    E-Print Network [OSTI]

    R. Smiljanic; L. Pasquini; F. Primas; P. Mazzali; D. Galli; G. Valle

    2008-01-07

    As part of a large survey of halo and thick disc stars, we found one halo star, HD 106038, exceptionally overabundant in beryllium. In spite of its low metallicity, [Fe/H] = -1.26, the star has log(Be/H) = -10.60, which is similar to the solar meteoritic abundance, log(Be/H) = -10.58. This abundance is more than ten times higher the abundance of stars with similar metallicity and cannot be explained by models of chemical evolution of the Galaxy that include the standard theory of cosmic-ray spallation. No other halo star exhibiting such a beryllium overabundance is known. In addition, overabundances of Li, Si, Ni, Y, and Ba are also observed. We suggest that all these chemical peculiarities, but the Ba abundance, can be simultaneously explained if the star was formed in the vicinity of a hypernova.

  15. The non-linear correlation function and the shapes of virialized halos

    E-Print Network [OSTI]

    Ravi K. Sheth; Bhuvnesh Jain

    1996-02-20

    The correlation function xi(r) of matter in the non-linear regime is assumed to be determined by the density profiles rho(r) and the mass distribution n(M) of virialized halos. The Press--Schechter approach is used to compute n(M), and the stable clustering hypothesis is used to determine the density profiles of these Press--Schechter halos. Thus, the shape and amplitude of xi(r) on small scales is related to the initial power spectrum of density fluctuations. The case of clustering from scale-free initial conditions is treated in detail. If n is the slope of the initial power spectrum of density fluctuations, then stable clustering requires that xi(r)\\propto r^{-gamma}, where gamma is a known function of n. If halo--halo correlations can be neglected, then rho(r)\\propto r^{-epsilon}, where epsilon = (gamma+3)/2 = 3(4+n)/(5+n). For all values of n of current interest, this slope is steeper than the value 3(3+n)/(4+n) that was obtained by Hoffman & Shaham in their treatment of the shapes of the outer regions of collapsed halos. Our main result is a prediction for the amplitude of the non-linear correlation function. The predicted amplitude and its dependence on n are in good quantitative agreement with N-body simulations of self-similar clustering. If stable clustering is a good approximation only inside the half-mass radii of Press--Schechter halos, then the density contrast required for the onset of stable clustering can be estimated. This density contrast is in the range ~300-600 and increases with the initial slope n, in agreement with estimates from N-body simulations.

  16. WEAK GALACTIC HALO-DWARF SPHEROIDAL CONNECTION FROM RR LYRAE STARS

    SciTech Connect (OSTI)

    Fiorentino, Giuliana [INAF-Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna (Italy); Bono, Giuseppe [Dipartimento di Fisica, Universitá di Roma Tor Vergata, Via della Ricerca Scientifica 1, I-00133 Roma (Italy); Monelli, Matteo; Gallart, Carme; Martínez-Vásquez, Clara E. [Instituto de Astrofísica de Canarias, Calle Via Lactea s/n, E-38205 La Laguna, Tenerife (Spain); Stetson, Peter B. [National Research Council, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada); Tolstoy, Eline [Kapteyn Astronomical Institute, University of Groningen, Postbus 800, 9700 AV Groningen (Netherlands); Salaris, Maurizio [Astrophysics Research Institute, Liverpool John Moores University IC2, Liverpool Science Park, 146 Brownlow Hill, Liverpool L35RF (United Kingdom); Bernard, Edouard J., E-mail: giuliana.fiorentino@oabo.inaf.it [SUPA, Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom)

    2015-01-01

    We discuss the role that dwarf galaxies may have played in the formation of the Galactic halo (Halo) using RR Lyrae stars (RRL) as tracers of their ancient stellar component. The comparison is performed using two observables (periods, luminosity amplitudes) that are reddening and distance independent. Fundamental mode RRL in 6 dwarf spheroidals (dSphs) and 11 ultra faint dwarf galaxies (?1300) show a Gaussian period distribution well peaked around a mean period of (Pab) = 0.610 ± 0.001 days (? = 0.03). The Halo RRL (?15,000) are characterized by a broader period distribution. The fundamental mode RRL in all the dSphs apart from Sagittarius are completely lacking in High Amplitude Short Period (HASP) variables, defined as those having P ? 0.48 days and A{sub V} ? 0.75 mag. Such variables are not uncommon in the Halo and among the globular clusters and massive dwarf irregulars. To further interpret this evidence, we considered 18 globulars covering a broad range in metallicity (–2.3 ? [Fe/H] ? –1.1) and hosting more than 35 RRL each. The metallicity turns out to be the main parameter, since only globulars more metal-rich than [Fe/H] ? –1.5 host RRL in the HASP region. This finding suggests that dSphs similar to the surviving ones do not appear to be the major building-blocks of the Halo. Leading physical arguments suggest an extreme upper limit of ?50% to their contribution. On the other hand, massive dwarfs hosting an old population with a broad metallicity distribution (Large Magellanic Cloud, Sagittarius) may have played a primary role in the formation of the Halo.

  17. Compact binary mergers as the origin of r-process elements in the Galactic halo

    SciTech Connect (OSTI)

    Ishimaru, Yuhri [Department of Material Science, International Christian University, 3-10-2 Osawa, Mitaka, Tokyo 181-8585 (Japan); Wanajo, Shinya [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Prantzos, Nikos [Institut d'Astrophysique de Paris, UMR7095 CNRS, Univ. P. and M. Curie, 98bis Bd. Arago, 75104 Paris (France)

    2014-05-02

    Compact binary mergers (of double neutron star and black hole-neutron star systems) are suggested to be the major site of the r-process elements in the Galaxy by recent hydrodynamical and nucleosynthesis studies. It has been pointed out, however, that estimated long lifetimes of compact binaries are in conflict with the presence of r-process-enhanced stars at the metallicity [Fe/H] ? ?3. To resolve this problem, we examine the role of compact binary mergers in the early Galactic chemical evolution on the assumption that our Galactic halo was formed from merging sub-halos. The chemical evolutions are modeled for sub-halos with their total stellar masses between 10{sup 4}M{sub ?} and 2 × 10{sup 8}M{sub ?}. The lifetimes of compact binaries are assumed to be 100 Myr (95%) and 1 Myr (5%) according to recent binary population synthesis studies. We find that the r-process abundances (relative to iron; [r/Fe]) start increasing at [Fe/H] ? ?3 if the star formation rates are smaller for less massive sub-halos. Our models also suggest that the star-to-star scatter of [r/Fe]'s observed in Galactic halo stars can be interpreted as a consequence of greater gas outflow rates for less massive sub-halos. In addition, the sub-solar [r/Fe]'s (observed as [Ba/Fe] ? ?1.5 for [Fe/H] < ?3) are explained by the contribution from the short-lived (? 1 Myr) binaries. Our result indicates, therefore, that compact binary mergers can be potentially the origin of the r-process elements throughout the Galactic history.

  18. Changes in the halo formation rates due to features in the primordial spectrum

    SciTech Connect (OSTI)

    Hazra, Dhiraj Kumar, E-mail: dhiraj@apctp.org [Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211019 (India)

    2013-03-01

    Features in the primordial scalar power spectrum provide a possible roadway to describe the outliers at the low multipoles in the WMAP data. Apart from the CMB angular power spectrum, these features can also alter the matter power spectrum and, thereby, the formation of the large scale structure. Carrying out a complete numerical analysis, we investigate the effects of primordial features on the formation rates of the halos. We consider a few different inflationary models that lead to features in the scalar power spectrum and an improved fit to the CMB data, and analyze the corresponding imprints on the formation of halos. Performing a Markov Chain Monte Carlo analysis with the WMAP seven year data and the SDSS halo power spectrum from LRG DR7 for the models of our interest, we arrive at the parameter space of the models allowed by the data. We illustrate that, inflationary potentials, such as the quadratic potential with sinusoidal modulations and the axion monodromy model, which generate certain repeated, oscillatory features in the inflationary perturbation spectrum, do not induce a substantial difference in the number density of halos at their best fit values, when compared with, say, a nearly scale invariant spectrum as is generated by the standard quadratic potential. However, we find that the number density and the formation rates of halos change by about 13–22% for halo masses ranging over 10{sup 4}–10{sup 14} M{sub s}un, for potential parameters that lie within 2-? around the best fit values arrived at from the aforesaid joint constraints. We briefly discuss the implications of our results.

  19. Gas infall into atomic cooling haloes: on the formation of protogalactic disks and supermassive black holes at z > 10

    E-Print Network [OSTI]

    Prieto, Joaquin; Haiman, Zoltan

    2013-01-01

    We have performed cosmo-hydro simulations using the RAMSES code to study atomic cooling (ACHs) haloes at z=10 with masses 5E7Msun10 to date. We examine the morphology, angular momentum (AM), thermodynamic, and turbulence of these haloes, in order to assess the prevalence of disks and supermassive black holes (SMBHs). We find no correlation between either the magnitude or the direction of the AM of the gas and its parent DM halo. Only 3 haloes form rotationally supported cores. Two of the most massive haloes form massive, compact overdense blobs. These blobs have an accretion rate ~0.5 Msun/yr (at a distance of 100 pc), and are possible sites of SMBH formation. Our results suggest that the degree of rotational support and the fate of the gas in a halo is determined by its large-scale environment and merger history. In particular, the two haloes forming blobs are located at knots of the cosmic web, cooled early on, and experienced many mergers. The gas in these haloes is lumpy and highly turbulent, with Mach N....

  20. Halo mass dependence of H I and O VI absorption: evidence for differential kinematics

    SciTech Connect (OSTI)

    Mathes, Nigel L.; Churchill, Christopher W.; Nielsen, Nikole M.; Trujillo-Gomez, Sebastian [New Mexico State University, Las Cruces, NM 88003 (United States); Kacprzak, Glenn G. [Swinburne University of Technology, Victoria 3122 (Australia); Charlton, Jane; Muzahid, Sowgat [The Pennsylvania State University, University Park, PA 16802 (United States)

    2014-09-10

    We studied a sample of 14 galaxies (0.1 < z < 0.7) using HST/WFPC2 imaging and high-resolution HST/COS or HST/STIS quasar spectroscopy of Ly?, Ly?, and O VI ??1031, 1037 absorption. The galaxies, having 10.8 ? log (M {sub h}/M {sub ?}) ? 12.2, lie within D = 300 kpc of quasar sightlines, probing out to D/R {sub vir} = 3. When the full range of M {sub h} and D/R {sub vir} of the sample are examined, ?40% of the H I absorbing clouds can be inferred to be escaping their host halo. The fraction of bound clouds decreases as D/R {sub vir} increases such that the escaping fraction is ?15% for D/R {sub vir} < 1, ?45% for 1 ? D/R {sub vir} < 2, and ?90% for 2 ? D/R {sub vir} < 3. Adopting the median mass log M {sub h}/M {sub ?} = 11.5 to divide the sample into 'higher' and 'lower' mass galaxies, we find a mass dependency for the hot circumgalactic medium kinematics. To our survey limits, O VI absorption is found in only ?40% of the H I clouds in and around lower mass halos as compared to ?85% around higher mass halos. For D/R {sub vir} < 1, lower mass halos have an escape fraction of ?65%, whereas higher mass halos have an escape fraction of ?5%. For 1 ? D/R {sub vir} < 2, the escape fractions are ?55% and ?35% for lower mass and higher mass halos, respectively. For 2 ? D/R {sub vir} < 3, the escape fraction for lower mass halos is ?90%. We show that it is highly likely that the absorbing clouds reside within 4R {sub vir} of their host galaxies and that the kinematics are dominated by outflows. Our finding of 'differential kinematics' is consistent with the scenario of 'differential wind recycling' proposed by Oppenheimer et al. We discuss the implications for galaxy evolution, the stellar to halo mass function, and the mass-metallicity relationship of galaxies.

  1. Core excitation effects in halo nuclei using a transformed oscillator basis

    SciTech Connect (OSTI)

    Lay, J. A.; Arias, J. M.; Moro, A. M. [Departamento de FAMN, Facultad de Fisica, Universidad de Sevilla, Apdo. 1065, E-41080 Sevilla (Spain); Gomez-Camacho, J. [Departamento de FAMN, Facultad de Fisica, Universidad de Sevilla, Apdo. 1065, E-41080 Sevilla, Spain and Centro Nacional de Aceleradores, Avda. Thomas A. Edison, E-41092, Sevilla (Spain)

    2013-06-10

    A recent generalization of the Transformed Harmonic Oscillator basis, intended to consider core excitations in the structure of one nucleon halo nuclei, is applied to the break up of {sup 11}Be. The reaction studied is {sup 11}Be+{sup 208}Pb at 69 MeV/nucleon. The experimental set up is designed to ensure pure dipole Coulomb excitations. Making use of the Equivalent Photon Method and the electromagnetic transition probabilities obtained with the transformed oscillator basis, a relevant contribution of the quadrupole excitations of the core is found. The inclusion of core excitations is, therefore, necessary for the correct extraction of the dipole electromagnetic transition probability of halo nuclei.

  2. Emittance dilution and halo creation during the first milliseconds after injection at the Fermilab Booster

    SciTech Connect (OSTI)

    Spentzouris, Panagiotis; Amundson, J.; /Fermilab

    2005-01-01

    During the past year, the Fermilab Booster has been pushed to record intensities in order to satisfy the needs of the Tevatron collider and neutrino programs. This high intensity makes the study of space-charge effects and halo formation highly relevant to optimizing Booster performance. We present measurements of beam width evolution, halo formation, and coherent tune shifts, emphasizing the experimental techniques used and the calibration of the measuring devices. We also use simulations utilizing the 3D space-charge code Synergia to study the physical origins of these effects.

  3. On the shoulders of giants: properties of the stellar halo and the Milky Way mass distribution

    SciTech Connect (OSTI)

    Kafle, Prajwal Raj; Sharma, Sanjib; Lewis, Geraint F.; Bland-Hawthorn, Joss

    2014-10-10

    Halo stars orbit within the potential of the Milky Way, and hence their kinematics can be used to understand the underlying mass distribution. However, the inferred mass distribution depends sensitively on assumptions made on the density and the velocity anisotropy profiles of the tracer population. Also, there is a degeneracy between the parameters of the halo and those of the disk or bulge. Most previous attempts that use halo stars have made arbitrary assumptions about these. In this paper, we decompose the Galaxy into three major components—a bulge, a Miyamoto-Nagai disk, and a Navarro-Frenk-White dark matter halo - and then model the kinematic data of the halo blue horizontal branch and K-giant stars from the Sloan Extension for Galactic Understanding and Exploration. Additionally, we use the gas terminal velocity curve and the Sgr A* proper motion. With the distance of the Sun from the center of the Galaxy R {sub ?} = 8.5 kpc, our kinematic analysis reveals that the density of the stellar halo has a break at 17.2{sub ?1.0}{sup +1.1} kpc and an exponential cutoff in the outer parts starting at 97.7{sub ?15.8}{sup +15.6} kpc. Also, we find that the tracer velocity anisotropy is radially biased with ? {sub s} = 0.4 ± 0.2 in the outer halo. We measure halo virial mass M {sub vir} to be 0.80{sub ?0.16}{sup +0.31}×10{sup 12} M{sub ?}, concentration c to be 21.1{sub ?8.3}{sup +14.8}, disk mass to be 0.95{sub ?0.30}{sup +0.24}×10{sup 11} M{sub ?}, disk scale length to be 4.9{sub ?0.4}{sup +0.4} kpc, and bulge mass to be 0.91{sub ?0.38}{sup +0.31}×10{sup 10} M{sub ?}. The halo mass is found to be small, and this has important consequences. The giant stars reveal that the outermost halo stars have low velocity dispersion, but interestingly this suggests a truncation of the stellar halo density rather than a small overall mass of the Galaxy. Our estimates of local escape velocity v{sub esc}=550.9{sub ?22.1}{sup +32.4} km s{sup ?1} and dark matter density ?{sub ?}{sup DM}=0.0088{sub ?0.0018}{sup +0.0024} M{sub ?} pc{sup ?3} (0.35{sub ?0.07}{sup +0.08} GeV cm{sup –3}) are in good agreement with recent estimates. Some of the above estimates, in particular M {sub vir}, are dependent on the adopted value of R {sub ?} and also on the choice of the outer power-law index of the tracer number density.

  4. The Century Survey Galactic Halo Project III: A Complete 4300 deg^2 Survey of Blue Horizontal Branch Stars in the Metal-Weak Thick Disk and Inner Halo

    E-Print Network [OSTI]

    Warren R. Brown; Timothy C. Beers; Ronald Wilhelm; Carlos Allende Prieto; Margaret J. Geller; Scott J. Kenyon; Michael J. Kurtz

    2007-11-19

    We present a complete spectroscopic survey of 2414 2MASS-selected blue horizontal branch (BHB) candidates selected over 4300 deg^2 of the sky. We identify 655 BHB stars in this non-kinematically selected sample. We calculate the luminosity function of field BHB stars and find evidence for very few hot BHB stars in the field. The BHB stars located at a distance from the Galactic plane |Z|<4 kpc trace what is clearly a metal-weak thick disk population, with a mean metallicity of [Fe/H]= -1.7, a rotation velocity gradient of dv_{rot}/d|Z|= -28+-3.4 km/s in the region |Z|<6 kpc, and a density scale height of h_Z= 1.26+-0.1 kpc. The BHB stars located at 5<|Z|<9 kpc are a predominantly inner-halo population, with a mean metallicity of [Fe/H]= -2.0 and a mean Galactic rotation of -4+-31 km/s. We infer the density of halo and thick disk BHB stars is 104+-37 kpc^-3 near the Sun, and the relative normalization of halo to thick-disk BHB stars is 4+-1% near the Sun.

  5. Metal halogen electrochemical cell

    SciTech Connect (OSTI)

    Walsh, F.M.

    1986-06-03

    An electrochemical cell is described having a metal anode selected from the group consisting of zinc and cadmium; a bromine cathode; and, an aqueous electrolyte containing a metal bromide, the metal having the same metal as the metal of the anode, the improvement comprising: a bromine complexing agent in the aqueous metal bromide electrolyte consisting solely of a tetraorgano substituted ammonium salt, which salt is soluble of water and forms and substantially water immiscible liquid bromine complex at temperatures in the range of about 10/sup 0/C. to about 60/sup 0/C. and wherein the tetraorgano substituted ammonium salt is selected from asymmetric quaternary ammonium compounds.

  6. Rare measurements of a sprite with halo event driven by a negative lightning discharge over Argentina

    E-Print Network [OSTI]

    Thomas, Jeremy N.

    Argentina M. J. Taylor,1 M. A. Bailey,1 P. D. Pautet,1 S. A. Cummer,2 N. Jaugey,2 J. N. Thomas,3,4 N. N measurements were made of a mesoscale thunderstorm observed on February 22­23, 2006 over northern Argentina of a sprite with halo event driven by a negative lightning discharge over Argentina, Geophys. Res. Lett., 35

  7. Influence of halo implant on leakage current and sheet resistance of ultrashallow p-n junctions

    E-Print Network [OSTI]

    Schroder, Dieter K.

    generation in the near-surface end-of-range damaged layer enhanced by trap-assisted tunneling. The reduced increase for USJs formed in halo-implanted profiles is explained by high electron and hole recombination should be addressed; electronic mail: vladimirf@frontiersemi.com 1588 1588J. Vac. Sci. Technol. B 25

  8. Why does the clustering of haloes depend on their formation history

    E-Print Network [OSTI]

    H. B. Sandvik; O. Moeller; J. Lee; S. D. M. White

    2006-10-06

    We discuss in the framework of the excursion set formalism a recent discovery from N-body simulations that the clustering of haloes of given mass depends on their formation history. We review why the standard implementation of this formalism is unable to explain such dependencies, and we show that this can, in principle, be rectified by implementing in full an ellipsoidal collapse model where collapse depends not only on the overdensity but also on the shape of the initial density field. We also present an alternative remedy for this deficiency, namely the inclusion of collapse barriers for pancakes and filaments, together with the assumption that formation history depends on when these barriers are crossed. We implement both these extensions in a generalised excursion set method, and run large Monte Carlo realisations to quantify the effects. Our results suggest that effects as large as those found in simulations can only arise in the excursion set formalism if the formation history of a halo does indeed depend on the size of its progenitor filaments and pancakes. We also present conditional distributions of progenitor pancakes and filaments for low-mass haloes identified at present epoch, and discuss a recent claim by Mo et.al. that most low-mass haloes were embedded in massive pancakes at $z\\sim 2$.

  9. Station-keeping Analysis for the Terrestrial Planet Formation in Halo Orbit

    E-Print Network [OSTI]

    Born, George

    nd Sun-Earth Libration Point OD Orbit Determination SKM Station-keeping Maneuver t0 A given initial: An Earth drift-away orbit, and a halo orbit about the second Sun-Earth libration point, EL2. This paper geometrically in a plane: four collectors evenly spaced in a line and one combiner offset perpendicularly from

  10. The Effect of Spatial Correlations on Merger Trees of Dark Matter Haloes

    E-Print Network [OSTI]

    Masahiro Nagashima; Naoteru Gouda

    1996-08-13

    The effects of spatial correlations of density fluctuations on merger histories of dark matter haloes (so-called `{\\it merger trees}') are analysed. We compare the mass functions of dark haloes derived by a new method for calculating merger trees, that proposed by Rodrigues \\& Thomas (RT), with those given by other methods such as the Block model, the Press-Schechter formula and our own formula in which the mass functions are analytically expressed in a way that takes into consideration the spatial correlations. It is found that the mass functions given by the new method are well fit by those given by our formula. We believe that new method (RT) {\\it naturally} and correctly takes into account the spatial correlations of the density fluctuations due to a calculated, grid-based realisation of the density fluctuations and so is very useful for estimating the merger tree accurately in a way that takes into consideration spatial correlations. Moreover, by applying our formula, we present an analytic expression which reproduces the mass function derived by the Block model. We therefore show clearly why and how the mass functions given by the new method and the Block model are different from each other. Furthermore, we note that the construction of merger trees is sensitive to the criterion of collapse and merging of overlapped haloes in cases in which two or more haloes happen to overlap. In fact, it is shown that the mass function is very much affected when the criterion of overlapping is changed.

  11. Probing Halo and Molecular States in Light, Neutron-Rich Nuclei

    E-Print Network [OSTI]

    N. A. Orr

    2002-02-05

    Selected topics on halo and molecular states in light, neutron-rich nuclei are discussed. In particular, work on $x\\alpha$:X$n$ structures is briefly reviewed. The use of proton radiative capture as a probe of clustering is also presented through the example provided by the $^6$He(p,$\\gamma$) reaction.

  12. A skewer survey of the Galactic halo from deep CFHT and INT images

    E-Print Network [OSTI]

    Pila-Díez, B; Kuijken, K; van der Burg, R F J; Hoekstra, H

    2015-01-01

    We study the density profile and shape of the Galactic halo using deep multicolour images from the MENeaCS and CCCP projects, over 33 fields selected to avoid overlap with the Galactic plane. Using multicolour selection and PSF homogenization techniques we obtain catalogues of F stars (near-main sequence turnoff stars) out to Galactocentric distances up to 60kpc. Grouping nearby lines of sight, we construct the stellar density profiles through the halo in eight different directions by means of photometric parallaxes. Smooth halo models are then fitted to these profiles. We find clear evidence for a steepening of the density profile power law index around R=20 kpc, from -2.50 +- 0.04 to -4.85 +- 0.04, and for a flattening of the halo towards the poles with best-fit axis ratio 0.63 +- 0.02. Furthermore, we cannot rule out a mild triaxiality (w>=0.8). We recover the signatures of well-known substructure and streams that intersect our lines of sight. These results are consistent with those derived from wider but ...

  13. Resonant Trapping in the Galactic Disc and Halo and its Relation with Moving Groups

    E-Print Network [OSTI]

    Moreno, Edmundo; Schuster, William

    2015-01-01

    With the use of a detailed Milky Way nonaxisymmetric potential, observationally and dynamically constrained, the e?ects of the bar and the spiral arms in the Galaxy are studied in the disc and in the stellar halo. Especially the trapping of stars in the disc and Galactic halo by resonances on the Galactic plane, induced by the Galactic bar, has been analysed in detail. To this purpose, a new method is presented to delineate the trapping regions using empirical diagrams of some orbital properties obtained in the Galactic potential. In these diagrams we plot in the inertial Galactic frame a characteristic orbital energy versus a characteristic orbital angular momentum, or versus the orbital Jacobi constant in the reference frame of the bar, when this is the only nonaxisymmetric component in the Galactic potential. With these diagrams some trapping regions are obtained in the disc and halo using a sample of disc stars and halo stars in the solar neighbourhood. We compute several families of periodic orbits on th...

  14. Three frontside full halo coronal mass ejections with a nontypical geomagnetic response

    E-Print Network [OSTI]

    Dasso, Sergio

    purposes, e.g., for satellite operations, radio communications, global positioning system applications, power grid, and pipeline maintenance. We analyze three frontside full halo coronal mass ejections (CMEs weaker geomagnetic responses. Therefore, these three events do not fit into the general statistical

  15. The Effect of Halo Mass on the HI Content of Galaxies in Groups and Clusters

    E-Print Network [OSTI]

    Yoon, Ilsang

    2015-01-01

    We combine data from the Sloan Digital Sky Survey (SDSS) and the Arecibo Legacy Fast ALFA Survey (ALFALFA) to study the cold atomic gas content of galaxies in groups and clusters in local universe. A careful cross-matching of galaxies in the SDSS, ALFALFA and SDSS group catalogs provides a sample of group galaxies with stellar masses $10^{8.4} M_{\\odot} \\le M_{*} \\le 10^{10.6} M_{\\odot}$ and group halo masses $10^{12.5} h^{-1} M_{\\odot} \\le M_h \\le 10^{15.0} h^{-1} M_{\\odot}$. Controlling our sample in stellar mass and redshift, we find no significant radial variation in the galaxy \\hi\\ gas-to-stellar mass ratio for the halo mass range in our sample. However, the fraction of galaxies detected in ALFALFA declines steadily towards the centers of groups with the effect being most prominent in the most massive halos. In the outskirts of massive halos a hint of a depressed detection fraction for low mass galaxies suggests pre-processing that decreases the \\hi\\ in these galaxies before they fall into massive cluste...

  16. Touching the void: A striking drop in stellar halo density beyond 50 kpc

    SciTech Connect (OSTI)

    Deason, A. J.; Rockosi, C. M.; Belokurov, V.; Koposov, S. E.

    2014-05-20

    We use A-type stars selected from Sloan Digital Sky Survey data release 9 photometry to measure the outer slope of the Milky Way stellar halo density profile beyond 50 kpc. A likelihood-based analysis is employed that models the ugr photometry distribution of blue horizontal branch and blue straggler stars. In the magnitude range 18.5 < g < 20.5, these stellar populations span a heliocentric distance range of: 10 ? D {sub BS}/kpc ? 75, 40 ? D {sub BHB}/kpc ? 100. Contributions from contaminants, such as QSOs, and the effect of photometric uncertainties, are also included in our modeling procedure. We find evidence for a very steep outer halo profile, with power-law index ? ? 6 beyond Galactocentric radii r = 50 kpc, and even steeper slopes favored (? ? 6-10) at larger radii. This result holds true when stars belonging to known overdensities, such as the Sagittarius stream, are included or excluded. We show that, by comparison to numerical simulations, stellar halos with shallower slopes at large distances tend to have more recent accretion activity. Thus, it is likely that the Milky Way has undergone a relatively quiet accretion history over the past several gigayears. Our measurement of the outer stellar halo profile may have important implications for dynamical mass models of the Milky Way, where the tracer density profile is strongly degenerate with total mass estimates.

  17. Satellites of LMCs: Close Friendships Ruined by Milky Way Mass Halos

    E-Print Network [OSTI]

    Deason, Alis J; Garrison-Kimmel, Shea; Belokurov, Vasily

    2015-01-01

    Motivated by the recent discovery of several dwarf galaxies near the Large Magellanic Cloud (LMC), we study the accretion of massive satellites onto Milky Way (MW)/M31-like halos using the ELVIS suite of N-body simulations. We identify 25 surviving subhalos near the expected mass of the LMC, and investigate the lower-mass satellites that were associated with these subhalos before they fell into the MW/M31 halos. Typically, 7% of the overall z=0 satellite population of MW/M31 halos were in a surviving LMC-group prior to falling into the MW/M31 halo. This fraction, however, can vary between 1% and 25%, being higher for groups with higher-mass and/or more recent infall times. Groups of satellites disperse rapidly in phase space after infall, and their distances and velocities relative to the group center become statistically similar to the overall satellite population after 4-8 Gyr. We quantify the likelihood that satellites were associated with an LMC-mass group as a function of both distance and velocity relat...

  18. X-ray Dust Scattering at Small Angles: The Complete Halo around GX13+1

    E-Print Network [OSTI]

    Randall K. Smith

    2008-05-04

    The exquisite angular resolution available with Chandra should allow precision measurements of faint diffuse emission surrounding bright sources, such as the X-ray scattering halos created by interstellar dust. However, the ACIS CCDs suffer from pileup when observing bright sources, and this creates difficulties when trying to extract the scattered halo near the source. The initial study of the X-ray halo around GX13+1 using only the ACIS-I detector done by Smith, Edgar & Shafer (2002) suffered from a lack of sensitivity within 50'' of the source, limiting what conclusions could be drawn. To address this problem, observations of GX13+1 were obtained with the Chandra HRC-I and simultaneously with the RXTE PCA. Combined with the existing ACIS-I data, this allowed measurements of the X-ray halo between 2-1000''. After considering a range of dust models, each assumed to be smoothly distributed with or without a dense cloud along the line of sight, the results show that there is no evidence in this data for a dense cloud near the source, as suggested by Xiang et al. (2005). Finally, although no model leads to formally acceptable results, the Weingartner & Draine (2001) and nearly all of the composite grain models from Zubko, Dwek & Arendt (2004) give poor fits.

  19. A distant radio mini-halo in the Phoenix galaxy cluster

    E-Print Network [OSTI]

    van Weeren, R J; Lal, D V; Andrade-Santos, F; Brüggen, M; de Gasperin, F; Forman, W R; Hoeft, M; Jones, C; Nuza, S E; Röttgering, H J A; Stroe, A

    2014-01-01

    We report the discovery of extended radio emission in the Phoenix cluster (SPT-CL J2344-4243, z=0.596) with the GMRT at 610 MHz. The diffuse emission extends over a region of at least 400-500 kpc and surrounds the central radio source of the Brightest Cluster Galaxy, but does not appear to be directly associated with it. We classify the diffuse emission as a radio mini-halo, making it the currently most distant mini-halo known. Radio mini-halos have been explained by synchrotron emitting particles re-accelerated via turbulence, possibly induced by gas sloshing generated from a minor merger event. Chandra observations show a non-concentric X-ray surface brightness distribution, which is consistent with this sloshing interpretation. The mini-halo has a flux density of $17\\pm5$ mJy, resulting in a 1.4 GHz radio power of ($10.4\\pm3.5) \\times 10^{24}$ W Hz$^{-1}$. The combined cluster emission, which includes the central compact radio source, is also detected in a shallow GMRT 156 MHz observation and together with...

  20. THE CLUSTERING AND HALO MASSES OF STAR-FORMING GALAXIES AT z < 1

    SciTech Connect (OSTI)

    Dolley, Tim; Brown, Michael J. I.; Pimbblet, Kevin A.; Palamara, David P.; Beare, Richard; Weiner, Benjamin J.; Jannuzi, Buell T.; Brodwin, Mark; Kochanek, C. S.; Dey, Arjun; Atlee, David W.

    2014-12-20

    We present clustering measurements and halo masses of star-forming galaxies at 0.2 < z < 1.0. After excluding active galactic nuclei (AGNs), we construct a sample of 22,553 24 ?m sources selected from 8.42 deg{sup 2} of the Spitzer MIPS AGN and Galaxy Evolution Survey of Boötes. Mid-infrared imaging allows us to observe galaxies with the highest star formation rates (SFRs), less biased by dust obscuration afflicting the optical bands. We find that the galaxies with the highest SFRs have optical colors that are redder than typical blue cloud galaxies, with many residing within the green valley. At z > 0.4 our sample is dominated by luminous infrared galaxies (LIRGs, L {sub TIR} > 10{sup 11} L {sub ?}) and is composed entirely of LIRGs and ultraluminous infrared galaxies (ULIRGs, L {sub TIR} > 10{sup 12} L {sub ?}) at z > 0.6. We observe weak clustering of r {sub 0} ? 3-6 h {sup –1} Mpc for almost all of our star-forming samples. We find that the clustering and halo mass depend on L {sub TIR} at all redshifts, where galaxies with higher L {sub TIR} (hence higher SFRs) have stronger clustering. Galaxies with the highest SFRs at each redshift typically reside within dark matter halos of M {sub halo} ? 10{sup 12.9} h {sup –1} M {sub ?}. This is consistent with a transitional halo mass, above which star formation is largely truncated, although we cannot exclude that ULIRGs reside within higher mass halos. By modeling the clustering evolution of halos, we connect our star-forming galaxy samples to their local descendants. Most star-forming galaxies at z < 1.0 are the progenitors of L ? 2.5 L {sub *} blue galaxies in the local universe, but star-forming galaxies with the highest SFRs (L {sub TIR} ? 10{sup 11.7} L {sub ?}) at 0.6 < z < 1.0 are the progenitors of early-type galaxies in denser group environments.

  1. Properties of Lithium-11 and Carbon-22 at leading order in halo effective field theory

    E-Print Network [OSTI]

    Bijaya Acharya; Daniel Phillips

    2015-08-11

    We study the $^{11}\\mathrm{Li}$ and $^{22}\\mathrm{C}$ nuclei at leading order (LO) in halo effective field theory (Halo EFT). Using the value of the $^{22}\\mathrm{C}$ rms matter radius deduced in Ref. [1] as an input in a LO calculation, we simultaneously constrained the values of the two-neutron (2$n$) separation energy of $^{22}\\mathrm{C}$ and the virtual-state energy of the $^{20}\\mathrm{C}-$neutron system (hereafter denoted $^{21}$C). The 1$-\\sigma$ uncertainty of the input rms matter radius datum, along with the theory error estimated from the anticipated size of the higher-order terms in the Halo EFT expansion, gave an upper bound of about 100 keV for the 2$n$ separation energy. We also study the electric dipole excitation of 2$n$ halo nuclei to a continuum state of two neutrons and the core at LO in Halo EFT. We first compare our results with the $^{11}\\mathrm{Li}$ data from a Coulomb dissociation experiment and obtain good agreement within the theoretical uncertainty of a LO calculation. We then obtain the low-energy spectrum of $B(E1)$ of this transition at several different values of the 2$n$ separation energy of $^{22}\\mathrm{C}$ and the virtual-state energy of $^{21}\\mathrm{C}$. Our predictions can be compared to the outcome of an ongoing experiment on the Coulomb dissociation of $^{22}\\mathrm{C}$ to obtain tighter constraints on the two- and three-body energies in the $^{22}\\mathrm{C}$ system.

  2. Quantifying the Cosmic Web I: The large-scale halo ellipticity-ellipticity and ellipticity-direction correlations

    E-Print Network [OSTI]

    Jounghun Lee; Volker Springel; Ue-Li Pen; Gerard Lemson

    2008-06-20

    The formation of dark matter halos tends to occur anisotropically along the filaments of the Cosmic Web, which induces both ellipticity-ellipticity (EE) correlations between the shapes of halos, as well as ellipticity-direction (ED) cross-correlations between halo shapes and the directions to neighboring halos. We analyze the halo catalogue and the semi-analytic galaxy catalogue of the recent Millennium Run Simulation to measure the EE and ED correlations numerically at four different redshifts (z=0, 0.5, 1 and 2). For the EE correlations, we find that (i) the major-axis correlation is strongest while the intermediate-axis correlation is weakest; (ii) the signal is significant at distances out to 10 Mpc/h; (iii) the signal decreases as z decreases; (iv) and its behavior depends strongly on the halo mass scale, with larger masses showing stronger correlations at large distances. For the ED correlations, we find that (i) the correlations are much stronger than the EE correlations, and are significant even out to distances of 50 Mpc/h; (ii) the signal also decreases as z decreases; (iii) and it increases with halo mass at all distances. We also provide empirical fitting functions for the EE and ED correlations. The EE correlations are found to scale linearly with the linear density correlation function, xi(r). While the ED cross-correlation is found to scale as xi^{1/2}(r) at large distances beyond 10 Mpc/h. The best-fit values of the fitting parameters for the EE and the ED correlations are all determined through chi^{2}-statistics. Our results may be useful for quantifying the filamentary distribution of dark matter halos over a wide range of scales.

  3. Tidal energy effects of dark matter halos on early-type galaxies

    E-Print Network [OSTI]

    Valentinuzzi, T; D'Onofrio, M

    2010-01-01

    Tidal interactions between neighboring objects span across the whole admissible range of lengths in nature: from, say, atoms to clusters of galaxies i.e. from micro to macrocosms. According to current cosmological theories, galaxies are embedded within massive non-baryonic dark matter (DM) halos, which affects their formation and evolution. It is therefore highly rewarding to understand the role of tidal interaction between the dark and luminous matter in galaxies. The current investigation is devoted to Early-Type Galaxies (ETGs), looking in particular at the possibility of establishing whether the tidal interaction of the DM halo with the luminous baryonic component may be at the origin of the so-called "tilt" of the Fundamental Plane (FP). The extension of the tensor virial theorem to two-component matter distributions implies the calculation of the self potential energy due to a selected subsystem, and the tidal potential energy induced by the other one. The additional assumption of homeoidally striated d...

  4. The modified dynamics (MOND) predicts an absolute maximum to the acceleration produced by `dark halos'

    E-Print Network [OSTI]

    Rafael Brada; Mordehai Milgrom

    1998-12-21

    We have recently discovered that the modified dynamics (MOND) implies some universal upper bound on the acceleration that can be contributed by a `dark halo'--assumed in a Newtonian analysis to account for the effects of MOND. Not surprisingly, the limit is of the order of the acceleration constant of the theory. This can be contrasted directly with the results of structure-formation simulations. The new limit is substantial and different from earlier MOND acceleration limits (discussed in connection with the MOND explanation of the Freeman law for galaxy disks, and the Fish law for ellipticals): It pertains to the `halo', and not to the observed galaxy; it is absolute, and independent of further physical assumptions on the nature of the galactic system; and it applies at all radii, whereas the other limits apply only to the mean acceleration in the system.

  5. The X-ray Halo of G21.5-0.9

    E-Print Network [OSTI]

    R. Bandiera; F. Bocchino

    2003-05-21

    The emission of the plerion G21.5-0.9 appears more extended in X rays than in radio. This is an unexpected result because it would imply that short-lived X-ray electrons may reach distances even larger than radio electrons. Applying an empirical relationship between dust scattering optical depth and photoelectric column density, the measured column density leads to a large optical depth at 1 keV, of about 1. Therefore we investigate the hypothesis that the detected halo be an effect of dust scattering, re-analyzing an Cal/PV XMM-Newton observation of G21.5-0.9 and critically examining it in terms of a dust scattering model. We also present a spectral analysis of a prominent extended feature in the northern sector of the halo.

  6. On the relevance of chaos for halo stars in the Solar Neighbourhood

    E-Print Network [OSTI]

    Maffione, Nicolás P; Cincotta, Pablo M; Giordano, Claudia M; Cooper, Andrew P; O'Shea, Brian W

    2015-01-01

    We show that diffusion due to chaotic mixing in the Neighbourhood of the Sun may not be as relevant as previously suggested in erasing phase space signatures of past Galactic accretion events. For this purpose, we analyse Solar Neighbourhood-like volumes extracted from cosmological simulations that naturally account for chaotic orbital behaviour induced by the strongly triaxial and cuspy shape of the resulting dark matter haloes, among other factors. In the approximation of an analytical static triaxial model, our results show that a large fraction of stellar halo particles in such local volumes have chaos onset times (i.e., the timescale at which stars commonly associated with chaotic orbits will exhibit their chaotic behaviour) significantly larger than a Hubble time. Furthermore, particles that do present a chaotic behaviour within a Hubble time do not exhibit significant diffusion in phase space.

  7. On the relevance of chaos for halo stars in the Solar Neighbourhood

    E-Print Network [OSTI]

    Nicolás P. Maffione; Facundo A. Gómez; Pablo M. Cincotta; Claudia M. Giordano; Andrew P. Cooper; Brian W. O'Shea

    2015-08-03

    We show that diffusion due to chaotic mixing in the Neighbourhood of the Sun may not be as relevant as previously suggested in erasing phase space signatures of past Galactic accretion events. For this purpose, we analyse Solar Neighbourhood-like volumes extracted from cosmological simulations that naturally account for chaotic orbital behaviour induced by the strongly triaxial and cuspy shape of the resulting dark matter haloes, among other factors. In the approximation of an analytical static triaxial model, our results show that a large fraction of stellar halo particles in such local volumes have chaos onset times (i.e., the timescale at which stars commonly associated with chaotic orbits will exhibit their chaotic behaviour) significantly larger than a Hubble time. Furthermore, particles that do present a chaotic behaviour within a Hubble time do not exhibit significant diffusion in phase space.

  8. Accurate calculations of the WIMP halo around the Sun and prospects for gamma ray detection

    E-Print Network [OSTI]

    Sofia Sivertsson; Joakim Edsjö

    2009-03-04

    Weakly interacting massive particles (WIMPs) can be captured by heavenly objects, like the Sun. Under the process of being captured by the Sun, they will build up a population of WIMPs around it, that will eventually sink to the core of the Sun. It has been argued with simpler estimates before that this halo of WIMPs around the Sun could be a strong enough gamma ray source to be a detectable signature for WIMP dark matter. We here revisit the problem using detailed Monte Carlo simulations and detailed composition and structure information about the Sun to estimate the size of the gamma ray flux. Compared to earlier estimates, we find that the gamma ray flux from WIMP annihilations in the Sun halo would be negligible and no current or planned detectors would even be able to detect this flux.

  9. Dark matter-radiation interactions: the impact on dark matter haloes

    E-Print Network [OSTI]

    J. A. Schewtschenko; R. J. Wilkinson; C. M. Baugh; C. Boehm; S. Pascoli

    2015-02-27

    Interactions between dark matter (DM) and radiation (photons or neutrinos) in the early Universe suppress density fluctuations on small mass scales. Here we perform a thorough analysis of structure formation in the fully non-linear regime using N-body simulations for models with DM-radiation interactions and compare the results to a traditional calculation in which DM only interacts gravitationally. Significant differences arise due to the presence of interactions, in terms of the number of low-mass DM haloes and their properties, such as their spin and density profile. These differences are clearly seen even for haloes more massive than the scale on which density fluctuations are suppressed. We also show that semi-analytical descriptions of the matter distribution in the non-linear regime fail to reproduce our numerical results, emphasizing the challenge of predicting structure formation in models with physics beyond collisionless DM.

  10. Carbon-19 in Halo EFT: Effective-range parameters from Coulomb-dissociation experiments

    E-Print Network [OSTI]

    B. Acharya; Daniel R. Phillips

    2013-06-15

    We study the Coulomb dissociation of the 19C nucleus in an effective field theory that uses the 18C core and the neutron as effective degrees of freedom and exploits the separation of scales in this halo system. We extract the effective-range parameters and the separation energy of the halo neutron from the experimental data taken at RIKEN by Nakamura et al. We obtain a value of (575 +/- 55(stat.) +/- 20(EFT)) keV for the one-neutron separation energy of 19C, and (7.75 +/- 0.35(stat.) +/- 0.3(EFT)) fm for the 18C-neutron scattering length. The width of the longitudinal momentum distribution predicted by EFT using this separation energy agrees well with the experimental data taken at NSCL by Bazin et al., reaffirming the dominance of the s-wave configuration of the valence neutron.

  11. Dark Matter annihilations in halos and high-redshift sources of reionization of the universe

    E-Print Network [OSTI]

    Vivian Poulin; Pasquale D. Serpico; Julien Lesgourgues

    2015-12-03

    It is well known that annihilations in the homogeneous fluid of dark matter (DM) can leave imprints in the cosmic microwave background (CMB) anisotropy power spectrum. However, the relevance of DM annihilations in halos for cosmological observables is still subject to debate, with previous works reaching different conclusions on this point. Also, all previous studies used a single type of parameterization for the astrophysical reionization, and included no astrophysical source for the heating of the intergalactic medium. In this work, we revisit these problems. When standard approaches are adopted, we find that the ionization fraction does exhibit a very particular (and potentially constraining) pattern, but the currently measurable optical depth to reionization is left almost unchanged: In agreement with the most of the previous literature, for plausible halo models we find that the modification of the signal with respect to the one coming from annihilations in the smooth background is tiny, below cosmic variance within currently allowed parameter space. However, if different and probably more realistic treatments of the astrophysical sources of reionization and heating are adopted, a more pronounced effect of the DM annihilation in halos is possible. We thus conclude that within currently adopted baseline models the impact of the virialised DM structures cannot be uncovered by CMB power spectra measurements, but a larger impact is possible if peculiar models are invoked for the redshift evolution of the DM annihilation signal or different assumptions are made for the astrophysical contributions. A better understanding (both theoretical and observational) of the reionization and temperature history of the universe, notably via the 21 cm signal, seems the most promising way for using halo formation as a tool in DM searches, improving over the sensitivity of current cosmological probes.

  12. Near-barrier Fusion Induced by Stable Weakly Bound and Exotic Halo Light Nuclei

    E-Print Network [OSTI]

    C. Beck; A. Sanchez i Zafra; A. Diaz-Torres; I. J. Thompson; N. Keeley; F. A. Souza

    2006-10-02

    The effect of breakup is investigated for the medium weight $^{6}$Li+$^{59}$Co system in the vicinity of the Coulomb barrier. The strong coupling of breakup/transfer channels to fusion is discussed within a comparison of predictions of the Continuum Discretized Coupled-Channels model which is also applied to $^{6}$He+$^{59}$Co a reaction induced by the borromean halo nucleus $^{6}$He.

  13. Searching for Gravitational Radiation from Binary Black Hole MACHOs in the Galactic Halo

    E-Print Network [OSTI]

    Duncan A. Brown

    2007-05-10

    The Laser Interferometer Gravitational Wave Observatory (LIGO) is one of a new generation of detectors of gravitational radiation. The existence of gravitational radiation was first predicted by Einstein in 1916, however gravitational waves have not yet been directly observed. One source of gravitation radiation is binary inspiral. Two compact bodies orbiting each other, such as a pair of black holes, lose energy to gravitational radiation. As the system loses energy the bodies spiral towards each other. This causes their orbital speed and the amount of gravitational radiation to increase, producing a characteristic ``chirp'' waveform in the LIGO sensitive band. In this thesis, matched filtering of LIGO science data is used to search for low mass binary systems in the halo of dark matter surrounding the Milky Way. Observations of gravitational microlensing events of stars in the Large Magellanic Cloud suggest that some fraction of the dark matter in the halo may be in the form of Massive Astrophysical Compact Halo Objects (MACHOs). It has been proposed that low mass black holes formed in the early universe may be a component of the MACHO population; some fraction of these black hole MACHOs will be in binary systems and detectable by LIGO. The inspiral from a MACHO binary composed of two 0.5 solar mass black holes enters the LIGO sensitive band around 40 Hz. The chirp signal increases in amplitude and frequency, sweeping through the sensitive band to 4400 Hz in 140 seconds. By using evidence from microlensing events and theoretical predictions of the population an upper limit is placed on the rate of black hole MACHO inspirals in the galactic halo.

  14. Deuteron stripping and pickup involving halo nuclei 11Be and 15C

    E-Print Network [OSTI]

    A. Deltuva

    2009-04-22

    Three-body calculations of (d,p) and (p,d) reactions involving one-neutron halo nuclei 11Be and 15C are performed using the framework of Faddeev-type scattering equations. Important effects of the optical potential nonlocality are found improving the description of the experimental data. The obtained values for the neutron spectroscopic factor are consistent with estimations from other approaches.

  15. HOT GAS HALOS AROUND DISK GALAXIES: CONFRONTING COSMOLOGICAL SIMULATIONS WITH OBSERVATIONS

    SciTech Connect (OSTI)

    Rasmussen, Jesper [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Sommer-Larsen, Jesper [Excellence Cluster Universe, Technische Universitaet Muenchen, Boltzmannstr. 2, D-85748 Garching bei Muenchen (Germany); Pedersen, Kristian; Toft, Sune; Grove, Lisbeth F. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Benson, Andrew [Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Mail Code 130-33, Pasadena, CA 91125 (United States); Bower, Richard G. [Institute for Computational Cosmology, University of Durham, South Road, Durham DH1 3LE (United Kingdom)], E-mail: jr@ociw.edu

    2009-05-20

    Models of disk galaxy formation commonly predict the existence of an extended reservoir of accreted hot gas surrounding massive spirals at low redshift. As a test of these models, we use X-ray and H{alpha} data of the two massive, quiescent edge-on spirals NGC 5746 and NGC 5170 to investigate the amount and origin of any hot gas in their halos. Contrary to our earlier claim, the Chandra analysis of NGC 5746, employing more recent calibration data, does not reveal any significant evidence for diffuse X-ray emission outside the optical disk, with a 3{sigma} upper limit to the halo X-ray luminosity of 4 x 10{sup 39} erg s{sup -1}. An identical study of the less massive NGC 5170 also fails to detect any extraplanar X-ray emission. By extracting hot halo properties of disk galaxies formed in cosmological hydrodynamical simulations, we compare these results to expectations for cosmological accretion of hot gas by spirals. For Milky-Way-sized galaxies, these high-resolution simulations predict hot halo X-ray luminosities which are lower by a factor of {approx}2 compared to our earlier results reported by Toft et al. We find the new simulation predictions to be consistent with our observational constraints for both NGC 5746 and NGC 5170, while also confirming that the hot gas detected so far around more actively star-forming spirals is in general probably associated with stellar activity in the disk. Observational results on quiescent disk galaxies at the high-mass end are nevertheless providing powerful constraints on theoretical predictions, and hence on the assumed input physics in numerical studies of disk galaxy formation and evolution.

  16. Ultra High Energy Cosmic Ray and UHE Neutrino-Z Showering in Dark Halos

    E-Print Network [OSTI]

    Daniele Fargion; P. G. De Sanctis Lucentini; M. Grossi; M. De Santis; Barbara Mele

    2002-01-03

    The Ultra High Energy Cosmic Ray (UHECR), by UHE neutrino-relic neutrino--Z showering in Hot Dark Halos (HDM), shows an energy spectra, an anisotropy following the relic neutrino masses and clustering in dark halo. The lighter are the relic neutrinos masses, the higher their corresponding Z resonance energy peaks. A twin light neutrino mass splitting may reflect into a twin Z resonance and a complex UHECR spectra modulation as a twin bump at at highest GZK energy cut-off. Each possible neutrino mass associates a characteristic dark halo size (galactic, local, super cluster) and its anisotropy due to our peculiar position within that dark matter distribution. The expected Z or WW,ZZ showering into proton-anti proton and neutron-anti neutron might correspond to peculiar clustering in observed UHECR at 10^{19}, 2 10^{19}, 4 10^{19} eV. A neutrino light HDM halo around a Mpc will allow to the UHECR neutron--anti-neutron secondary component at E_n> 10^{20} eV (due to Z decay) to arise playing a role comparable with the charged p-bar{p} ones. Their un-deflected n-bar{n} flight is shorter leading to a prompt and hard UHECR trace pointing toward the original UHECR source direction. The direct proton-antiproton pairs are split and spread by random magnetic fields into a more diluted and smeared and lower energy UHECR signal around the original source direction. Additional prompt TeVs signals by synchrotron radiation of electro-magnetic Z showering must also occur solving the Infrared-TeV cut-off. The observed hard doublet and triplets spectra, their time and space clustering already favour the rising key role of UHECR n-bar n secondaries originated by neutrino-Z tail shower.

  17. A dynamical and kinematical model of the Galactic stellar halo and possible implications for galaxy formation scenarios

    E-Print Network [OSTI]

    J. Sommer-Larsen; T. C. Beers; C. Flynn; R. Wilhelm; P. R. Christensen

    1996-10-23

    We re-analyse the kinematics of the system of blue horizontal branch field (BHBF) stars in the Galactic halo (in particular the outer halo), fitting the kinematics with the model of radial and tangential velocity dispersions in the halo as a function of galactocentric distance r proposed by Sommer-Larsen, Flynn & Christensen (1994), using a much larger sample (almost 700) of BHBF stars. The basic result is that the character of the stellar halo velocity ellipsoid changes markedly from radial anisotropy at the sun to tangential anisotropy in the outer parts of the Galactic halo (r greater than approx 20 kpc). Specifically, the radial component of the stellar halo's velocity ellipsoid decreases fairly rapidly beyond the solar circle, from approx 140 +/- 10 km/s at the sun, to an asymptotic value of 89 +/- 19 km/s at large r. The rapid decrease in the radial velocity dispersion is matched by an increase in the tangential velocity dispersion, with increasing r. Our results may indicate that the Galaxy formed hierarchically (partly or fully) through merging of smaller subsystems - the 'bottom-up' galaxy formation scenario, which for quite a while has been favoured by most theorists and recently also has been given some observational credibility by HST observations of a potential group of small galaxies, at high redshift, possibly in the process of merging to a larger galaxy (Pascarelle et al 1996).

  18. The outer regions of the giant Virgo galaxy M87 II. Kinematic separation of stellar halo and intracluster light

    E-Print Network [OSTI]

    Longobardi, Alessia; Gerhard, Ortwin; Hanuschik, Reinhard

    2015-01-01

    We present a spectroscopic study of 287 Planetary Nebulas (PNs) in a total area of ~0.4 deg^2 around the BCG M87 in Virgo A. With these data we can distinguish the stellar halo from the co-spatial intracluster light (ICL). PNs were identified from their narrow and symmetric redshifted lambda 5007\\4959 Angstrom [OIII] emission lines, and the absence of significant continuum. We implement a robust technique to measure the halo velocity dispersion from the projected phase-space to identify PNs associated with the M87 halo and ICL. The velocity distribution of the spectroscopically confirmed PNs is bimodal, containing a narrow component centred on the systemic velocity of the BCG and an off-centred broader component, that we identify as halo and ICL, respectively. Halo and ICPN have different spatial distributions: the halo PNs follow the galaxy's light, whereas the ICPNs are characterised by a shallower power-law profile. The composite PN number density profile shows the superposition of different PN populations...

  19. The metallicity distribution of the halo and the satellites of the Milky way in the hierarchical merging paradigm

    E-Print Network [OSTI]

    Nikos Prantzos

    2008-07-09

    To account for the observed differential metallicity distribution (DMD) of the Milky Way halo, a semi-analytical model is presented in the framework of the hierarchical merging paradigm for structure formation. It is assumed that the Milky Way halo is composed of a number of sub-haloes with properties either as observed in the dwarf satellite galaxies of the Local group (shape of metallicity distribution, effective yield) or derived from calculations of structure formation (sub-halo distribution function). With reasonable assumptions for the parameters involved, we find that the overall shape and effective yield of the Galactic halo DMD can be reproduced in the framework of such a simple model. The low metallicity tail of the DMD presents a defficiency of stars with respect to the simple model predictions (akin to the G-dwarf problem in the solar neighborhood); it is suggested that an early infall phase can account for that problem, as well as for the observed DMDs of dwarf satellite galaxies.Accretion of galaxies similar (but not identical) to the progenitors of present day dwarf satellites of the Milky Way may well have formed the Galactic halo.

  20. Using chemical tagging to redefine the interface of the Galactic disk and halo

    E-Print Network [OSTI]

    Hawkins, Keith; Masseron, Thomas; Gilmore, Gerry

    2015-01-01

    We present a chemical abundance distribution study in 14 $\\alpha$, odd-Z, even-Z, light, and Fe-peak elements of approximately 3200 intermediate metallicity giant stars from the APOGEE survey. The main aim of our analysis is to explore the Galactic disk-halo transition region between -1.20 $chemical difference (and similarities) between these components. In this paper, we show that there is an $\\alpha$-poor and $\\alpha$-rich sequence within both the metal-poor and intermediate metallicity regions. Using the Galactic rest-frame radial velocity and spatial positions, we further separate our sample into the canonical Galactic components. We then studied the abundances ratios, of Mg, Ti, Si, Ca, O, S, Al, C+N, Na, Ni, Mn, V, and K for each of the components and found the following: (1) the $\\alpha$-poor halo subgroup is chemically distinct in the $\\alpha$-elements (particularly O, Mg, and S), Al, C+N, and Ni from the $\\alpha$-rich halo, consistent with the literature ...

  1. Non-local bias in the halo bispectrum with primordial non-Gaussianity

    E-Print Network [OSTI]

    Tellarini, Matteo; Tasinato, Gianmassimo; Wands, David

    2015-01-01

    The statistics of large-scale structure in our Universe can discriminate between different scenarios for the origin of primordial density perturbations. Primordial non-Gaussianity can lead to a scale-dependent bias in the density of collapsed halos relative to the underlying matter density. The galaxy power spectrum already provides constraints on local-type primordial non-Gaussianity complementary to those from the cosmic microwave background, while the bispectrum contains additional shape information and has the potential to outperform CMB constraints in future. We develop the bias model for the halo density contrast in the presence of local-type primordial non-Gaussianity, deriving a bivariate expansion up to second order in terms of the local linear matter density contrast and the local gravitational potential in Lagrangian coordinates. We show how the evolution from linear to non-linear matter density introduces the non-local, tidal term in the halo model, while the presence of local-type non-Gaussianity...

  2. Fusion and Direct Reactions of Halo Nuclei at Energies around the Coulomb Barrier

    E-Print Network [OSTI]

    N. Keeley; R. Raabe; N. Alamanos; J. L. Sida

    2007-02-16

    The present understanding of reaction processes involving light unstable nuclei at energies around the Coulomb barrier is reviewed. The effect of coupling to direct reaction channels on elastic scattering and fusion is investigated, with the focus on halo nuclei. A list of definitions of processes is given, followed by a review of the experimental and theoretical tools and information presently available. The effect of couplings on elastic scattering and fusion is studied with a series of model calculations within the coupled-channels framework. The experimental data on fusion are compared to "bare" no-coupling one-dimensional barrier penetration model calculations. On the basis of these calculations and comparisons with experimental data, conclusions are drawn from the observation of recurring features. The total fusion cross sections for halo nuclei show a suppression with respect to the "bare" calculations at energies just above the barrier that is probably due to single neutron transfer reactions. The data for total fusion are also consistent with a possible sub-barrier enhancement; however, this observation is not conclusive and other couplings besides the single-neutron channels would be needed in order to explain any actual enhancement. We find that a characteristic feature of halo nuclei is the dominance of direct reactions over fusion at near and sub-barrier energies; the main part of the cross section is related to neutron transfers, while calculations indicate only a modest contribution from the breakup process.

  3. Shrinking galaxy disks with fountain-driven accretion from the halo

    SciTech Connect (OSTI)

    Elmegreen, Bruce G.; Struck, Curtis; Hunter, Deidre A. E-mail: curt@iastate.edu

    2014-12-01

    Star formation in most galaxies requires cosmic gas accretion because the gas consumption time is short compared to the Hubble time. This accretion presumably comes from a combination of infalling satellite debris, cold flows, and condensation of hot halo gas at the cool disk interface, perhaps aided by a galactic fountain. In general, the accretion will have a different specific angular momentum than the part of the disk that receives it, even if the gas comes from the nearby halo. The gas disk then expands or shrinks over time. Here we show that condensation of halo gas at a rate proportional to the star formation rate in the fountain model will preserve an initial shape, such as an exponential, with a shrinking scale length, leaving behind a stellar disk with a slightly steeper profile of younger stars near the center. This process is slow for most galaxies, producing imperceptible radial speeds, and it may be dominated by other torques, but it could be important for blue compact dwarfs, which tend to have large, irregular gas reservoirs and steep blue profiles in their inner stellar disks.

  4. Halo and Bulge/Disk globular clusters in the S0 galaxy NGC 1380

    E-Print Network [OSTI]

    Markus Kissler-Patig; Tom Richtler; Jesper Storm; Massimo Della Valle

    1997-06-30

    We investigated the globular cluster system of the S0 galaxy NGC 1380 in the Fornax cluster with deep BVR photometry. We identified two, presumably old, populations of globular clusters. The blue globular clusters seem to be counterparts to the halo globular clusters in our Milky Way. They have comparable colors and magnitudes, are spherically distributed around the elliptical galaxy but have a very flat surface density profile. The red population follows the stellar light in ellipticity and position angle, has a similar magnitude distribution to the blue clusters, and a surface density profile comparable to that of globular clusters in other Fornax ellipticals. From their colors the red clusters appear slightly more metal rich then the metal rich globular clusters in the Milky way. We associate this red population with the bulge and disk of NGC 1380. While these two populations are compatible with a merger formation, we unfortunately see no other hint in favor nor against a past merger event in this galaxy. This would be the first identification of halo and bulge globular clusters in an early--type galaxy by their colors and spatial distribution, and could hint to the presence of halo and bulge globular clusters in all galaxies.

  5. Milky Way mass and potential recovery using tidal streams in a realistic halo

    SciTech Connect (OSTI)

    Bonaca, Ana; Geha, Marla; Küpper, Andreas H. W.; Johnston, Kathryn V.; Diemand, Jürg; Hogg, David W.

    2014-11-01

    We present a new method for determining the Galactic gravitational potential based on forward modeling of tidal stellar streams. We use this method to test the performance of smooth and static analytic potentials in representing realistic dark matter halos, which have substructure and are continually evolving by accretion. Our FAST-FORWARD method uses a Markov Chain Monte Carlo algorithm to compare, in six-dimensional phase space, an 'observed' stream to models created in trial analytic potentials. We analyze a large sample of streams that evolved in the Via Lactea II (VL2) simulation, which represents a realistic Galactic halo potential. The recovered potential parameters are in agreement with the best fit to the global, present-day VL2 potential. However, merely assuming an analytic potential limits the dark matter halo mass measurement to an accuracy of 5%-20%, depending on the choice of analytic parameterization. Collectively, the mass estimates using streams from our sample reach this fundamental limit, but individually they can be highly biased. Individual streams can both under- and overestimate the mass, and the bias is progressively worse for those with smaller perigalacticons, motivating the search for tidal streams at galactocentric distances larger than 70 kpc. We estimate that the assumption of a static and smooth dark matter potential in modeling of the GD-1- and Pal5-like streams introduces an error of up to 50% in the Milky Way mass estimates.

  6. Genetically modified halos: towards controlled experiments in $\\Lambda$CDM galaxy formation

    E-Print Network [OSTI]

    Roth, Nina; Peiris, Hiranya V

    2015-01-01

    We propose a method to generate `genetically-modified' (GM) initial conditions for high-resolution simulations of galaxy formation in a cosmological context. Building on the Hoffman-Ribak algorithm, we start from a reference simulation with fully random initial conditions, then make controlled changes to specific properties of a single halo (such as its mass and merger history). The algorithm demonstrably makes minimal changes to other properties of the halo and its environment, allowing us to isolate the impact of a given modification. As a significant improvement over previous work, we are able to calculate the abundance of the resulting objects relative to the $\\Lambda$CDM reference cosmology. Our approach can be applied to a wide range of cosmic structures and epochs; here we study two problems as a proof-of-concept. First, we investigate the change in density profile and concentration as the collapse time of three individual halos are varied at fixed final mass, showing good agreement with previous stati...

  7. TITLE AUTHORS SUBJECT SUBJECT RELATED DESCRIPTION PUBLISHER AVAILABILI...

    Office of Scientific and Technical Information (OSTI)

    Jason R Hollomon Brad Dillon Heather E Snowden Swan Lesley J LED light emitting diode CFL incandescent halogen lamp bulb TCLP STLC TTLC WET hazardous waste electronic waste e...

  8. Deep SAURON Spectral-Imaging of the diffuse Lyman-alpha halo LAB1 in SSA22

    E-Print Network [OSTI]

    Richard Bower; S. L. Morris; R. Bacon; R. J. Wilman; M. Sullivan; S. C. Chapman; R. L. Davies; P. T. de Zeeuw; E. Emsellem

    2004-02-19

    We have used the SAURON panoramic integral field spectrograph to study the structure of the Ly-alpha emission-line halo, LAB1, surrounding the sub-millimeter galaxy SMM J221726+0013. This emission-line halo was discovered during a narrow-band imaging survey of the z=3.1 large-scale structure in the SSA22 region. Our observations trace the emission halo out to almost 100 kpc from the sub-millimeter source and identify two distinct Ly-alpha `mini-haloes' around the nearby Lyman-break galaxies. The main emission region has a broad line profile, with variations in the line profile seeming chaotic and lacking evidence for a coherent velocity structure. The data also suggests that Ly-alpha emission is suppressed around the sub-mm source. Interpretation of the line structure needs care because Ly-alpha may be resonantly scattered, leading to complex radiative transfer effects, and we suggest that the suppression in this region arises because of such effects. We compare the structure of the central emission-line halo with local counter-parts, and find that the emission line halo around NGC 1275 in the Perseus cluster may be a good local analogue, although the high redshift halo is factor of ~100 more luminous and appears to have higher velocity broadening. Around the Lyman-break galaxy C15, the emission line is narrower, and a clear shear in the emission wavelength is seen. A plausible explanation for the line profile is that the emission gas is expelled from C15 in a bipolar outflow, similar to that seen in M82.

  9. Applications of Cu{sub 2}O octahedral particles on ITO glass in photocatalytic degradation of dye pollutants under a halogen tungsten lamp

    SciTech Connect (OSTI)

    Zhai, Wei; Sun, Fengqiang; Chen, Wei; Zhang, Lihe; Min, Zhilin; Li, Weishan

    2013-11-15

    Graphical abstract: - Highlights: • Photocatalytic activity of Cu{sub 2}O octahedral microcrystals on ITO glass was studied. • They showed high abilities in degradation of methylene blue in the presence of H{sub 2}O{sub 2}. • H{sub 2}O{sub 2} amount could affect the degradation efficiency. • Such particles could be easily recycled and still kept high activity. • Many dye pollutants and their mixtures could be efficiently degraded. - Abstract: Cu{sub 2}O octahedral microcrystals were prepared on the ITO glass by galvanostatic electrodeposition in CuSO{sub 4} solution with poly(vinylpryrrolidone) as the surfactant. By controlling the electrodeposition time, the microcrystals could be randomly distributed on the ITO glass and separated from each other, resulting in as many as possible (1 1 1) crystalline planes were exposed. Such microcrystals immobilized on ITO glass were employed in photodegradation of dye pollutants in the presence of H{sub 2}O{sub 2} under a 150 W halogen tungsten lamp. The photodegradation of methylene blue was taken as an example to evaluate the photocatalytic activities of the octahedral Cu{sub 2}O microcrystals. Effects of electrodeposition time and H{sub 2}O{sub 2} amount on the degradation efficiency was discussed, giving the optimum conditions and the corresponding degradation mechanism. The catalyst showed high ability in degradation of methylene blue, methyl orange, rhodamine B, eosin B and their mixtures under identical conditions.

  10. The metallicity distribution of the halo and the satellites of the Milky way in the hierarchical merging paradigm

    E-Print Network [OSTI]

    Prantzos, Nikos

    2008-01-01

    To account for the observed differential metallicity distribution (DMD) of the Milky Way halo, a semi-analytical model is presented in the framework of the hierarchical merging paradigm for structure formation. It is assumed that the Milky Way halo is composed of a number of sub-haloes with properties either as observed in the dwarf satellite galaxies of the Local group (shape of metallicity distribution, effective yield) or derived from calculations of structure formation (sub-halo distribution function). With reasonable assumptions for the parameters involved, we find that the overall shape and effective yield of the Galactic halo DMD can be reproduced in the framework of such a simple model. The low metallicity tail of the DMD presents a defficiency of stars with respect to the simple model predictions (akin to the G-dwarf problem in the solar neighborhood); it is suggested that an early infall phase can account for that problem, as well as for the observed DMDs of dwarf satellite galaxies.Accretion of gal...

  11. Effect of basic physical parameters to control plasma meniscus and beam halo formation in negative ion sources

    SciTech Connect (OSTI)

    Miyamoto, K. [Naruto University of Education, 748 Nakashima, Takashima, Naruto-cho, Naruto-shi, Tokushima 772-8502 (Japan)] [Naruto University of Education, 748 Nakashima, Takashima, Naruto-cho, Naruto-shi, Tokushima 772-8502 (Japan); Okuda, S.; Nishioka, S.; Hatayama, A. [Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan)] [Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan)

    2013-09-14

    Our previous study shows that the curvature of the plasma meniscus causes the beam halo in the negative ion sources: the negative ions extracted from the periphery of the meniscus are over-focused in the extractor due to the electrostatic lens effect, and consequently become the beam halo. In this article, the detail physics of the plasma meniscus and beam halo formation is investigated with two-dimensional particle-in-cell simulation. It is shown that the basic physical parameters such as the H{sup ?} extraction voltage and the effective electron confinement time significantly affect the formation of the plasma meniscus and the resultant beam halo since the penetration of electric field for negative ion extraction depends on these physical parameters. Especially, the electron confinement time depends on the characteristic time of electron escape along the magnetic field as well as the characteristic time of electron diffusion across the magnetic field. The plasma meniscus penetrates deeply into the source plasma region when the effective electron confinement time is short. In this case, the curvature of the plasma meniscus becomes large, and consequently the fraction of the beam halo increases.

  12. THE COS-HALOS SURVEY: RATIONALE, DESIGN, AND A CENSUS OF CIRCUMGALACTIC NEUTRAL HYDROGEN

    SciTech Connect (OSTI)

    Tumlinson, Jason; Thom, Christopher; Sembach, Kenneth R. [Space Telescope Science Institute, Baltimore, MD (United States); Werk, Jessica K.; Prochaska, J. Xavier [UCO/Lick Observatory, University of California, Santa Cruz, CA (United States); Tripp, Todd M.; Katz, Neal; Meiring, Joseph D. [Department of Astronomy, University of Massachusetts, Amherst, MA (United States); Davé, Romeel [University of the Western Cape, South African Astronomical Observatories, and African Institute for Mathematical Sciences, Cape Town (South Africa); Oppenheimer, Benjamin D. [Leiden Observatory, Leiden University, 2300 RA Leiden (Netherlands); Ford, Amanda Brady [Steward Observatory, University of Arizona, Tucson, AZ (United States); O'Meara, John M. [Department of Chemistry and Physics, Saint Michael's College, Colchester, VT (United States); Peeples, Molly S. [Center for Galaxy Evolution, University of California Los Angeles, Los Angeles, CA (United States); Weinberg, David H. [Department of Astronomy, The Ohio State University, Columbus, OH (United States)

    2013-11-01

    We present the design and methods of the COS-Halos survey, a systematic investigation of the gaseous halos of 44 z = 0.15-0.35 galaxies using background QSOs observed with the Cosmic Origins Spectrograph aboard the Hubble Space Telescope. This survey has yielded 39 spectra of z{sub em} ? 0.5 QSOs with S/N ?10-15 per resolution element. The QSO sightlines pass within 150 physical kpc of the galaxies, which span early and late types over stellar mass log M{sub *}/M{sub ?} = 9.5-11.5. We find that the circumgalactic medium exhibits strong H I, averaging ? 1 Å in Ly? equivalent width out to 150 kpc, with 100% covering fraction for star-forming galaxies and 75% covering for passive galaxies. We find good agreement in column densities between this survey and previous studies over similar range of impact parameter. There is weak evidence for a difference between early- and late-type galaxies in the strength and distribution of H I. Kinematics indicate that the detected material is bound to the host galaxy, such that ?> 90% of the detected column density is confined within ±200 km s{sup –1} of the galaxies. This material generally exists well below the halo virial temperatures at T ?< 10{sup 5} K. We evaluate a number of possible origin scenarios for the detected material, and in the end favor a simple model in which the bulk of the detected H I arises in a bound, cool, low-density photoionized diffuse medium that is generic to all L* galaxies and may harbor a total gaseous mass comparable to galactic stellar masses.

  13. The Dark Matter Halos of Massive, Relaxed Galaxy Clusters Observed With Chandra

    SciTech Connect (OSTI)

    Schmidt, Robert W.; /Heidelberg, Astron. Rechen Inst.; Allen, S.W.; /KIPAC, Menlo Park

    2006-10-11

    We use the Chandra X-ray Observatory to study the dark matter halos of 34 massive, dynamically relaxed galaxy clusters, spanning the redshift range 0.06 < z < 0.7. The observed dark matter and total mass (dark-plus-luminous matter) profiles can be approximated by the Navarro Frenk & White (hereafter NFW) model for cold dark matter (CDM) halos; for {approx} 80 percent of the clusters, the NFW model provides a statistically acceptable fit. In contrast, the singular isothermal sphere model can, in almost every case, be completely ruled out. We observe a well-defined mass-concentration relation for the clusters with a normalization and intrinsic scatter in good agreement with the predictions from simulations. The slope of the mass-concentration relation, c {infinity} M{sub vir}{sup a}/(1 + z){sup b} with a = -0.41 {+-} 0.11 at 95 percent confidence, is steeper than the value a {approx} -0.1 predicted by CDM simulations for lower mass halos. With the slope a included as a free fit parameter, the redshift evolution of the concentration parameter, b = 0.54 {+-} 0.47 at 95 percent confidence, is also slower than, but marginally consistent with, the same simulations (b {approx} 1). Fixing a {approx} -0.1 leads to an apparent evolution that is significantly slower, b = 0.20 {+-} 0.45, although the goodness of fit in this case is significantly worse. Using a generalized NFW model, we find the inner dark matter density slope, a, to be consistent with unity at 95 percent confidence for the majority of clusters. Combining the results for all clusters for which the generalized NFW model provides a good description of the data, we measure ? = 0.88 {+-} 0.29 at 95 percent confidence, in agreement with CDM model predictions.

  14. Predicting Galaxy Star Formation Rates via the Co-evolution of Galaxies and Halos

    SciTech Connect (OSTI)

    Watson, Douglas F.; Hearin, Andrew P.; Berlind, Andreas A.; Becker, Matthew R.; Behroozi, Peter S.; Skibba, Ramin A.; Reyes, Reinabelle; Zentner, Andrew R.

    2014-03-06

    In this paper, we test the age matching hypothesis that the star formation rate (SFR) of a galaxy is determined by its dark matter halo formation history, and as such, that more quiescent galaxies reside in older halos. This simple model has been remarkably successful at predicting color-based galaxy statistics at low redshift as measured in the Sloan Digital Sky Survey (SDSS). To further test this method with observations, we present new SDSS measurements of the galaxy two-point correlation function and galaxy-galaxy lensing as a function of stellar mass and SFR, separated into quenched and star forming galaxy samples. We find that our age matching model is in excellent agreement with these new measurements. We also employ a galaxy group finder and show that our model is able to predict: (1) the relative SFRs of central and satellite galaxies, (2) the SFR-dependence of the radial distribution of satellite galaxy populations within galaxy groups, rich groups, and clusters and their surrounding larger scale environments, and (3) the interesting feature that the satellite quenched fraction as a function of projected radial distance from the central galaxy exhibits an approx r-.15 slope, independent of environment. The accurate prediction for the spatial distribution of satellites is intriguing given the fact that we do not explicitly model satellite-specific processes after infall, and that in our model the virial radius does not mark a special transition region in the evolution of a satellite, contrary to most galaxy evolution models. The success of the model suggests that present-day galaxy SFR is strongly correlated with halo mass assembly history.

  15. A MEGACAM SURVEY OF OUTER HALO SATELLITES. II. BLUE STRAGGLERS IN THE LOWEST STELLAR DENSITY SYSTEMS

    SciTech Connect (OSTI)

    Santana, Felipe A.; Munoz, Ricardo R.; Geha, Marla; Cote, Patrick; Stetson, Peter; Simon, Joshua D.; Djorgovski, S. G. E-mail: rmunoz@das.uchile.cl

    2013-09-10

    We present a homogeneous study of blue straggler stars across 10 outer halo globular clusters, 3 classical dwarf spheroidal galaxies, and 9 ultra-faint galaxies based on deep and wide-field photometric data taken with MegaCam on the Canada-France-Hawaii Telescope. We find blue straggler stars to be ubiquitous among these Milky Way satellites. Based on these data, we can test the importance of primordial binaries or multiple systems on blue straggler star formation in low-density environments. For the outer halo globular clusters, we find an anti-correlation between the specific frequency of blue stragglers and absolute magnitude, similar to that previously observed for inner halo clusters. When plotted against density and encounter rate, the frequency of blue stragglers is well fit by a single trend with a smooth transition between dwarf galaxies and globular clusters; this result points to a common origin for these satellites' blue stragglers. The fraction of blue stragglers stays constant and high in the low encounter rate regime spanned by our dwarf galaxies, and decreases with density and encounter rate in the range spanned by our globular clusters. We find that young stars can mimic blue stragglers in dwarf galaxies only if their ages are 2.5 {+-} 0.5 Gyr and they represent {approx}1%-7% of the total number of stars, which we deem highly unlikely. These results point to mass-transfer or mergers of primordial binaries or multiple systems as the dominant blue straggler formation mechanism in low-density systems.

  16. Galaxy Mergers and Dark Matter Halo Mergers in LCDM: Mass, Redshift, and Mass-Ratio Dependence

    SciTech Connect (OSTI)

    Stewart, Kyle R.; Bullock, James S.; Barton, Elizabeth J.; Wechsler, Risa H.; /KIPAC, Menlo Park /SLAC

    2009-08-03

    We employ a high-resolution LCDM N-body simulation to present merger rate predictions for dark matter halos and investigate how common merger-related observables for galaxies - such as close pair counts, starburst counts, and the morphologically disturbed fraction - likely scale with luminosity, stellar mass, merger mass ratio, and redshift from z = 0 to z = 4. We provide a simple 'universal' fitting formula that describes our derived merger rates for dark matter halos a function of dark halo mass, merger mass ratio, and redshift, and go on to predict galaxy merger rates using number density-matching to associate halos with galaxies. For example, we find that the instantaneous merger rate of m/M > 0.3 mass ratio events into typical L {approx}> fL{sub *} galaxies follows the simple relation dN/dt {approx_equal} 0.03(1+f)Gyr{sup -1} (1+z){sup 2.1}. Despite the rapid increase in merger rate with redshift, only a small fraction of > 0.4L{sub *} high-redshift galaxies ({approx} 3% at z = 2) should have experienced a major merger (m/M > 0.3) in the very recent past (t < 100 Myr). This suggests that short-lived, merger-induced bursts of star formation should not contribute significantly to the global star formation rate at early times, in agreement with observational indications. In contrast, a fairly high fraction ({approx} 20%) of those z = 2 galaxies should have experienced a morphologically transformative merger within a virial dynamical time. We compare our results to observational merger rate estimates from both morphological indicators and pair-fraction based determinations between z = 0-2 and show that they are consistent with our predictions. However, we emphasize that great care must be made in these comparisons because the predicted observables depend very sensitively on galaxy luminosity, redshift, overall mass ratio, and uncertain relaxation timescales for merger remnants. We show that the majority of bright galaxies at z = 3 should have undergone a major merger (> 0.3) in the last 700 Myr and conclude that mergers almost certainly play an important role in delivering baryons and influencing the kinematic properties of Lyman Break Galaxies (LBGs).

  17. Halo effective field theory constrains the solar Beryllium-7 + proton -> Boron-8 + photon rate

    E-Print Network [OSTI]

    Xilin Zhang; Kenneth M. Nollett; D. R. Phillips

    2015-07-26

    We report an improved low-energy extrapolation of the cross section for the process Beryllium-7+proton -> Boron-8+photon, which determines the Boron-8 neutrino flux from the Sun. Our extrapolant is derived from Halo Effective Field Theory (EFT) at next-to-leading order. We apply Bayesian methods to determine the EFT parameters and the low-energy S-factor, using measured cross sections and scattering lengths as inputs. Asymptotic normalization coefficients of Boron-8 are tightly constrained by existing radiative capture data, and contributions to the cross section beyond external direct capture are detected in the data at E prediction for S(E).

  18. On the reliability of merger-trees and the mass growth histories of dark matter haloes

    E-Print Network [OSTI]

    N. Hiotelis; A. Del Popolo

    2005-08-24

    We have used merger trees realizations to study the formation of dark matter haloes. The construction of merger-trees is based on three different pictures about the formation of structures in the Universe. These pictures include: the spherical collapse (SC), the ellipsoidal collapse (EC) and the non-radial collapse (NR). The reliability of merger-trees has been examined comparing their predictions related to the distribution of the number of progenitors, as well as the distribution of formation times, with the predictions of analytical relations. The comparison yields a very satisfactory agreement. Subsequently, >.........

  19. Do radio mini-halos and gas heating in cool-core clusters have a common origin?

    E-Print Network [OSTI]

    Bravi, Luca; Brunetti, Gianfranco

    2015-01-01

    In this letter we present a study of the central regions of cool-core clusters hosting radio mini-halos, which are diffuse synchrotron sources extended on cluster-scales surrounding the radio-loud brightest cluster galaxy. We aim to investigate the interplay between the thermal and non-thermal components in the intra-cluster medium in order to get more insights into these radio sources, whose nature is still unclear. It has recently been proposed that turbulence plays a role for heating the gas in cool cores. By assuming that mini-halos are powered by the same turbulence, we expect that the integrated radio luminosity of mini-halos, $\

  20. Primordial pollution of globular clusters within their host dwarfs embedded in dark matter halos at high redshifts

    E-Print Network [OSTI]

    Kenji Bekki

    2005-12-19

    Recent observational studies have revealed star-to-star abundance inhomogeneity among light elements (e.g., C, N, O, Na, and Al) of stars on the main sequence in the Galactic globular clusters (GCs). One of promising interpretations for this result is that the observed abundance inhomogeneity is due to the second generation of stars formed from ejecta of the first generation of evolved stars (e.g., AGB stars) within GCs. However it remains unclear whether and how this primordial pollution can occur within GCs. We here propose a new scenario in which primordial pollution of GCs is highly likely to occur if GCs are located in the central regions of high redshift dark matter subhalos that can host low-mass dwarf galaxies. In this scenario, gas ejected from the first generation of stars of GCs can be effectively trapped in the deep gravitational potential of their host halos and consequently can be consumed for the formation of the second generation of stars without losing a significant amount of gas by ram pressure stripping of interstellar and intergalactic medium. During merging of these halos with the proto-Galaxy, the halos are completely destroyed owing to the strong tidal field of the Galaxy. The self-polluted GCs located initially in the central regions of the halos can survive from tidal destruction owing to their compactness and finally become the Galactic halo GCs. In this scenario, ejecta of field stars surrounding the central GCs can be also converted into stars within their host dwarfs and finally become the second generation of stars of GCs. We also discuss the origin of the difference in the degree of abundance inhomogeneity between different GCs, such as $\\omega$ Centauri and NGC 6752, in terms of the difference in physical properties between host halos from which GC originate.

  1. Three-Dimensional Numerical Simulations of Thermal-Gravitational Instability in Protogalactic Halo Environment

    E-Print Network [OSTI]

    Chang Hyun Baek; Hyesung Kang; Jongsoo Kim; Dongsu Ryu

    2005-06-08

    We study thermal-gravitational instability in simplified models for protogalactic halos using three-dimensional hydrodynamic simulations. The simulations followed the evolution of gas with radiative cooling down to T = 10^4 K, background heating, and self-gravity. Then cooled and condensed clouds were identified and their physical properties were examined in detail. During early stage clouds start to form around initial density peaks by thermal instability. Small clouds appear first and they are pressure-bound. Subsequently, the clouds grow through compression by the background pressure as well as gravitational infall. During late stage cloud-cloud collisions become important, and clouds grow mostly through gravitational merging. Gravitationally bound clouds with mass M_c > ~6 X 10^6 Msun are found in the late stage. They are approximately in virial equilibrium and have radius R_c = \\~150 - 200 pc. Those clouds have gained angular momentum through tidal torque as well as merging, so they have large angular momentum with the spin parameter ~ 0.3. The clouds formed in a denser background tend to have smaller spin parameters. We discuss briefly the implications of our results on the formation of protoglobular cluster clouds in protogalactic halos. (abridged)

  2. Quantifying (dis)agreement between direct detection experiments in a halo-independent way

    SciTech Connect (OSTI)

    Feldstein, Brian; Kahlhoefer, Felix, E-mail: brian.feldstein@physics.ox.ac.uk, E-mail: felix.kahlhoefer@physics.ox.ac.uk [Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP (United Kingdom)

    2014-12-01

    We propose an improved method to study recent and near-future dark matter direct detection experiments with small numbers of observed events. Our method determines in a quantitative and halo-independent way whether the experiments point towards a consistent dark matter signal and identifies the best-fit dark matter parameters. To achieve true halo independence, we apply a recently developed method based on finding the velocity distribution that best describes a given set of data. For a quantitative global analysis we construct a likelihood function suitable for small numbers of events, which allows us to determine the best-fit particle physics properties of dark matter considering all experiments simultaneously. Based on this likelihood function we propose a new test statistic that quantifies how well the proposed model fits the data and how large the tension between different direct detection experiments is. We perform Monte Carlo simulations in order to determine the probability distribution function of this test statistic and to calculate the p-value for both the dark matter hypothesis and the background-only hypothesis.

  3. The Stellar Populations of NGC 3109: Another Dwarf Irregular Galaxy with a Population II Stellar Halo

    E-Print Network [OSTI]

    Dante Minniti; Albert Zijlstra; M. Victoria Alonso

    1998-10-29

    We have obtained V and I-band photometry for about 17500 stars in the field of the dwarf irregular galaxy NGC3109, located in the outskirts of the Local Group. The photometry allows us to study the stellar populations present inside and outside the disk of this galaxy. From the VI color-magnitude diagram we infer metallicities and ages for the stellar populations in the main body and in the halo of NGC3109. The stars in the disk of this galaxy have a wide variety of ages, including very young stars with approximately 10^7 yr. Our main result is to establish the presence of a halo consisting of population II stars, extending out to about 4.5 arcmin (or 1.8 kpc) above and below the plane of this galaxy. For these old stars we derive an age of > 10 Gyr and a metallicity of [Fe/H] = -1.8 +/- 0.2. We construct a deep luminosity function, obtaining an accurate distance modulus (m-M)_0 = 25.62 +/- 0.1 for this galaxy based on the I-magnitude of the red giant branch (RGB) tip and adopting E(V-I) = 0.05.

  4. High-velocity gas towards the LMC resides in the Milky Way halo

    E-Print Network [OSTI]

    Richter, P; Werner, K; Rauch, T

    2015-01-01

    To explore the origin of high-velocity gas in the direction of the Large Magellanic Cloud (LMC) we analyze absorption lines in the ultraviolet spectrum of a Galactic halo star that is located in front of the LMC at d=9.2 kpc distance. We study the velocity-component structure of low and intermediate metal ions in the spectrum of RXJ0439.8-6809, as obtained with the Cosmic Origins Spectrograph (COS) onboard HST, and measure equivalent widths and column densities for these ions. We supplement our COS data with a Far-Ultraviolet Spectroscopic Explorer spectrum of the nearby LMC star Sk-69 59 and with HI 21cm data from the Leiden-Argentina-Bonn (LAB) survey. Metal absorption towards RXJ0439.8-6809 is unambiguously detected in three different velocity components near v_LSR=0,+60, and +150 km/s. The presence of absorption proves that all three gas components are situated in front of the star, thus being located in the disk and inner halo of the Milky Way. For the high-velocity cloud (HVC) at v_LSR=+150 km/s we deri...

  5. Beryllium in the Ultra-Lithium-Deficient,Metal-Poor Halo Dwarf, G186-26

    E-Print Network [OSTI]

    Ann Merchant Boesgaard; Megan C. Novicki

    2005-09-16

    The vast majority of low-metal halo dwarfs show a similar amount of Li; this has been attributed to the Li that was produced in the Big Bang. However, there are nine known halo stars with T $>$ 5900 K and [Fe/H] $<$ $-$1.0 that are ultra-Li-deficient. We have looked for Be in the very low metallicity star, G 186-26 at [Fe/H] = $-$2.71, which is one of the ultra-Li-deficient stars. This star is also ultra-Be deficient. Relative to Be in the Li-normal stars at [Fe/H] = $-$2.7, G 182-26 is down in Be by more than 0.8 dex. Of two potential causes for the Li-deficiency -- mass-transfer in a pre-blue straggler or extra rotationally-induced mixing in a star that was initially a very rapid rotator -- the absence of Be favors the blue-straggler hypothesis, but the rotation model cannot be ruled-out completely.

  6. The derivation of constraints on the msugra parameter space from the entropy of dark matter halos

    SciTech Connect (OSTI)

    Cabral-Rosetti, L. G.; Mondragon, M.; Nellen, L.; Nunez, D.; Sussmann, R.; Zavala, J.

    2009-04-20

    We derive an expression for the entropy of a present dark matter halo described by a Navarro-Frenk-White modified model with a central core. We obtain an expression for the relic abundance of neutralinos by comparing this entropy of the halo with the value it had during the freeze-out era. Using WMAP observations, we constrain the parameter space for mSUGRA models. Combining our results with the usual abundance criteria, we are able to discriminate clearly among different validity regions for tan {beta} values. For this, we require both criteria to be consistent within a 2{sigma} bound of the WMAP observations for the relic density: 0.112<{omega}h{sup 2}<0.122. We find that for sgn {mu} = +1, small values of tan {beta} are not favored; only for tan {beta}{approx}50 are both criteria significantly consistent. Both criteria allow us to put a lower bound on the neutralino mass, m{sub {chi}}{>=}141 GeV.

  7. The COS-Halos survey: physical conditions and baryonic mass in the low-redshift circumgalactic medium

    SciTech Connect (OSTI)

    Werk, Jessica K.; Prochaska, J. Xavier; Tejos, Nicolas [UCO/Lick Observatory, University of California, Santa Cruz, CA (United States); Tumlinson, Jason; Peeples, Molly S.; Fox, Andrew J.; Thom, Christopher; Bordoloi, Rongmon [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD (United States); Tripp, Todd M.; Katz, Neal [Department of Astronomy, University of Massachusetts, Amherst, MA (United States); Lehner, Nicolas [Department of Physics and Astronomy, University of Notre Dame, South Bend, IN (United States); O'Meara, John M. [Department of Chemistry and Physics, Saint Michael's College, Colchester, VT (United States); Ford, Amanda Brady [Astronomy Department, University of Arizona, Tucson, AZ 85721 (United States); Oppenheimer, Benjamin D. [Leiden Observatory, Leiden University, NL-2300 RA Leiden (Netherlands); Davé, Romeel [University of the Western Cape, Bellville, Cape Town 7535 (South Africa); Weinberg, David H., E-mail: jwerk@ucolick.org [Department of Astronomy, The Ohio State University, Columbus, OH (United States)

    2014-09-01

    We analyze the physical conditions of the cool, photoionized (T ?10{sup 4} K) circumgalactic medium (CGM) using the COS-Halos suite of gas column density measurements for 44 gaseous halos within 160 kpc of L ? L* galaxies at z ? 0.2. These data are well described by simple photoionization models, with the gas highly ionized (n {sub H} {sub II}/n {sub H} ? 99%) by the extragalactic ultraviolet background. Scaling by estimates for the virial radius, R {sub vir}, we show that the ionization state (tracked by the dimensionless ionization parameter, U) increases with distance from the host galaxy. The ionization parameters imply a decreasing volume density profile n {sub H} = (10{sup –4.2±0.25})(R/R {sub vir}){sup –0.8±0.3}. Our derived gas volume densities are several orders of magnitude lower than predictions from standard two-phase models with a cool medium in pressure equilibrium with a hot, coronal medium expected in virialized halos at this mass scale. Applying the ionization corrections to the H I column densities, we estimate a lower limit to the cool gas mass M{sub CGM}{sup cool}>6.5×10{sup 10} M {sub ?} for the volume within R < R {sub vir}. Allowing for an additional warm-hot, O VI-traced phase, the CGM accounts for at least half of the baryons purported to be missing from dark matter halos at the 10{sup 12} M {sub ?} scale.

  8. Interpreting short gamma-ray burst progenitor kicks and time delays using the host galaxy-dark matter halo connection

    SciTech Connect (OSTI)

    Behroozi, Peter S. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Ramirez-Ruiz, Enrico [Department of Astronomy and Astrophysics, University of California Santa Cruz, CA 95064 (United States); Fryer, Christopher L. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2014-09-10

    Nearly 20% of short gamma-ray bursts (sGRBs) have no observed host galaxies. Combining this finding with constraints on galaxies' dark matter halo potential wells gives strong limits on the natal kick velocity distribution for sGRB progenitors. For the best-fitting velocity distribution, one in five sGRB progenitors receives a natal kick above 150 km s{sup –1}, consistent with merging neutron star models but not with merging white dwarf binary models. This progenitor model constraint is robust to a wide variety of systematic uncertainties, including the sGRB progenitor time-delay model, the Swift redshift sensitivity, and the shape of the natal kick velocity distribution. We also use constraints on the galaxy-halo connection to determine the host halo and host galaxy demographics for sGRBs, which match extremely well with available data. Most sGRBs are expected to occur in halos near 10{sup 12} M {sub ?} and in galaxies near 5 × 10{sup 10} M {sub ?} (L {sub *}); unobserved faint and high-redshift host galaxies contribute a small minority of the observed hostless sGRB fraction. We find that sGRB redshift distributions and host galaxy stellar masses weakly constrain the progenitor time-delay model; the active versus passive fraction of sGRB host galaxies may offer a stronger constraint. Finally, we discuss how searches for gravitational wave optical counterparts in the local universe can reduce follow-up times using these findings.

  9. GALAXY HALO TRUNCATION AND GIANT ARC SURFACE BRIGHTNESS RECONSTRUCTION IN THE CLUSTER MACSJ1206.2-0847

    SciTech Connect (OSTI)

    Eichner, Thomas; Seitz, Stella; Monna, Anna [Universitaets-Sternwarte Muenchen, Scheinerstr. 1, D-81679 Muenchen (Germany); Suyu, Sherry H. [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Halkola, Aleksi [Institute of Medical Engineering, University of Luebeck, Ratzeburger Allee 160 23562 Luebeck (Germany); Umetsu, Keiichi [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China); Zitrin, Adi [Institut fuer Theoretische Astrophysik, ZAH, Albert-Ueberle-Strasse 2, D-69120 Heidelberg (Germany); Coe, Dan; Postman, Marc; Koekemoer, Anton; Bradley, Larry [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21208 (United States); Rosati, Piero [ESO-European Southern Observatory, D-85748 Garching bei Muenchen (Germany); Grillo, Claudio; Host, Ole [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Balestra, Italo [Max-Planck-Institut fuer Extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching (Germany); Zheng, Wei; Lemze, Doron [Department of Physics and Astronomy, The Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Broadhurst, Tom [Department of Theoretical Physics, University of the Basque Country, P.O. Box 644, E-48080 Bilbao (Spain); Moustakas, Leonidas [Jet Propulsion Laboratory, California Institute of Technology, MS 169-327, Pasadena, CA 91109 (United States); Molino, Alberto [Instituto de Astrofisica de Andalucia (CSIC), C/Camino Bajo de Huetor 24, Granada E-18008 (Spain); and others

    2013-09-10

    In this work, we analyze the mass distribution of MACSJ1206.2-0847, particularly focusing on the halo properties of its cluster members. The cluster appears relaxed in its X-ray emission, but has a significant amount of intracluster light that is not centrally concentrated, suggesting that galaxy-scale interactions are still ongoing despite the overall relaxed state. The cluster lenses 12 background galaxies into multiple images and one galaxy at z = 1.033 into a giant arc and its counterimage. The multiple image positions and the surface brightness (SFB) distribution of the arc, which is bent around several cluster members, are sensitive to the cluster galaxy halo properties. We model the cluster mass distribution with a Navarro-Frenk-White profile and the galaxy halos with two parameters for the mass normalization and the extent of a reference halo assuming scalings with their observed near-infrared light. We match the multiple image positions at an rms level of 0.''85 and can reconstruct the SFB distribution of the arc in several filters to a remarkable accuracy based on this cluster model. The length scale where the enclosed galaxy halo mass is best constrained is about 5 effective radii-a scale in between those accessible to dynamical and field strong-lensing mass estimates on the one hand and galaxy-galaxy weak-lensing results on the other hand. The velocity dispersion and halo size of a galaxy with m{sub 160W,AB} = 19.2 and M{sub B,Vega} = -20.7 are {sigma} = 150 km s{sup -1} and r Almost-Equal-To 26 {+-} 6 kpc, respectively, indicating that the halos of the cluster galaxies are tidally stripped. We also reconstruct the unlensed source, which is smaller by a factor of {approx}5.8 in area, demonstrating the increase in morphological information due to lensing. We conclude that this galaxy likely has star-forming spiral arms with a red (older) central component.

  10. Prediction Space Weather Using an Asymmetric Cone Model for Halo CMEs

    E-Print Network [OSTI]

    G. Michalek; N. Gopalswamy; S. Yashiro

    2007-10-24

    Halo coronal mass ejections (HCMEs) are responsible of the most severe geomagnetic storms. A prediction of their geoeffectiveness and travel time to Earth's vicinity is crucial to forecast space weather. Unfortunately coronagraphic observations are subjected to projection effects and do not provide true characteristics of CMEs. Recently, Michalek (2006, {\\it Solar Phys.}, {\\bf237}, 101) developed an asymmetric cone model to obtain the space speed, width and source location of HCMEs. We applied this technique to obtain the parameters of all front-sided HCMEs observed by the SOHO/LASCO experiment during a period from the beginning of 2001 until the end of 2002 (solar cycle 23). These parameters were applied for the space weather forecast. Our study determined that the space speeds are strongly correlated with the travel times of HCMEs within Earth's vicinity and with the magnitudes related to geomagnetic disturbances.

  11. Ultra-High Energy Cosmic Rays and Neutron-Decay Halos from Gamma Ray Bursts

    E-Print Network [OSTI]

    C. D. Dermer

    2001-03-20

    Simple arguments concerning power and acceleration efficiency show that ultra-high energy cosmic rays (UHECRS) with energies >~ 10^{19} eV could originate from GRBs. Neutrons formed through photo-pion production processes in GRB blast waves leave the acceleration site and travel through intergalactic space, where they decay and inject a very energetic proton and electron component into intergalactic space. The neutron-decay protons form a component of the UHECRs, whereas the neutron-decay electrons produce optical/X-ray synchrotron and gamma radiation from Compton-scattered background radiation. A significant fraction of galaxies with GRB activity should be surrounded by neutron-decay halos of characteristic size ~ 100 kpc.

  12. Domain Wall Model in the Galactic Bose-Einstein Condensate Halo

    E-Print Network [OSTI]

    J. C. C. de Souza; M. O. C. Pires

    2013-05-22

    We assume that the galactical dark matter halo, considered composed of an axionlike particles Bose-Einstein condensate \\cite{pir12}, can present topological defects, namely domain walls, arising as the dark soliton solution for the Gross-Pitaevskii equation in a self-graviting potential. We investigate the influence that such substructures would have in the gravitational interactions within a galaxy. We find that, for the simple domain wall model proposed, the effects are too small to be identified, either by means of a local measurement of the gradient of the gravitational field or by analysing galaxy rotation curves. In the first case, the gradient of the gravitational field in the vicinity of the domain wall would be $10^{-31}\\; (m/s^2)/m$. In the second case, the ratio of the tangential velocity correction of a star due to the presence of the domain wall to the velocity in the spherical symmetric case would be $10^{-8}$.

  13. Polytropic transonic galactic outflows in a dark matter halo with a central black hole

    E-Print Network [OSTI]

    Igarashi, Asuka; Nitta, Shin-ya

    2015-01-01

    Polytropic transonic solutions of spherically symmetric and steady galactic winds in the gravitational potential of a dark matter halo (DMH) with a supermassive black hole (SMBH) are studied. The solutions are classified in terms of their topological features, and the gravitational potential of the SMBH adds a new branch to the transonic solutions generated by the gravity of the DMH. The topological types of the transonic solutions depend on the mass distribution, the amount of supplied energy, the polytropic index $\\gamma$, and the slope $\\alpha$ of the DMH mass distribution. When $\\alpha$ becomes larger than a critical value $\\alpha_\\mathrm{c}$, the transonic solution types change dramatically. Further, our model predicts that it is possible for a slowly accelerating outflow to exist, even in quiescent galaxies with small $\\gamma$. This slowly accelerating outflow differs from those considered in many of the previous studies focusing on supersonic outflows in active star-forming galaxies. In addition, our m...

  14. Direct versus indirect detection in mSUGRA with self-consistent halo models

    E-Print Network [OSTI]

    Joakim Edsjo; Mia Schelke; Piero Ullio

    2004-05-21

    We perform a detailed analysis of the detection prospects of neutralino dark matter in the mSUGRA framework. We focus on models with a thermal relic density, estimated with high accuracy using the DarkSUSY package, in the range favored by current precision cosmological measurements. Direct and indirect detection rates are computed implementing two models for the dark matter halo, tracing opposite regimes for the phase of baryon infall, with fully consistent density profiles and velocity distribution functions. This has allowed, for the first time, a fully consistent comparison between direct and indirect detection prospects. We discuss all relevant regimes in the mSUGRA parameter space, underlining relevant effects, and providing the basis for extending the discussion to alternative frameworks. In general, we find that direct detection and searches for antideuterons in the cosmic rays seems to be the most promising ways to search for neutralinos in these scenarios.

  15. Light bending in the galactic halo by Rindler-Ishak method

    SciTech Connect (OSTI)

    Bhattacharya, Amrita; Nandi, Kamal K.; Isaev, Ruslan; Scalia, Massimo; Cattani, Carlo E-mail: subfear@gmail.com E-mail: ccattani@unisa.it

    2010-09-01

    After the work of Rindler and Ishak, it is now well established that the bending of light is influenced by the cosmological constant ? appearing in the Schwarzschild-de Sitter spacetime. We show that their method, when applied to the exact Mannheim-Kazanas-de Sitter solution of the Weyl conformal gravity, nicely yields the expected answer together with several other physically interesting new terms. Apart from ?, the solution is parametrized by a conformal parameter ?, which is known to play a dominant role in the galactic halo gravity. The application of the method yields exactly the same ?? correction to Schwarzschild bending as obtained by standard methods. Different cases are analyzed, which include some corrections to the special cases considered in the original paper by Rindler and Ishak.

  16. Galactic Halos and Black Holes in Non-Canonical Scalar Field Theories

    E-Print Network [OSTI]

    Ratindranath Akhoury; Christopher S. Gauthier

    2008-06-03

    We consider static spherically symmetric solutions of a general scalar field theory with non-standard kinetic energy coupled to gravity with a view to explain dark matter halos as a coherent state of the scalar field. Consistent solutions are found with a smooth scalar profile which can describe observed rotation curves. Some of the solutions have negative scalar energy density near the origin though the total energy is positive definite. The solutions with positive energy density everywhere have a steeper rotation curve near the origin than those that don't. We also reconsider the no scalar hair theorems for black holes with emphasis on asymptotic boundary conditions and super-luminal propagation. Some modifications and extensions of previous analyses are discussed.

  17. Galactic Halos and Black Holes in Non-Canonical Scalar Field Theories

    E-Print Network [OSTI]

    Akhoury, Ratindranath

    2008-01-01

    We consider static spherically symmetric solutions of a general scalar field theory with non-standard kinetic energy coupled to gravity with a view to explain dark matter halos as a coherent state of the scalar field. Consistent solutions are found with a smooth scalar profile which can describe observed rotation curves. Some of the solutions have negative scalar energy density near the origin though the total energy is positive definite. The solutions with positive energy density everywhere have a steeper rotation curve near the origin than those that don't. We also reconsider the no scalar hair theorems for black holes with emphasis on asymptotic boundary conditions and super-luminal propagation. Some modifications and extensions of previous analyses are discussed.

  18. Fusion reactions with the one-neutron halo nucleus 15C

    E-Print Network [OSTI]

    M. Alcorta; K. E. Rehm; B. B. Back; S. Bedoor; P. F. Bertone; C. M. Deibel; B. DiGiovine; H. Esbensen; J. P. Greene; C. R. Hoffmann; C. L. Jiang; J. C. Lighthall; S. T. Marley; R. C. Pardo; M. Paul; A. M. Rogers; C. Ugalde; A. H. Wuosmaa

    2011-04-06

    The structure of 15C, with an s1/2 neutron weakly bound to a closed-neutron shell nucleus 14C, makes it a prime candidate for a one-neutron halo nucleus. We have for the first time studied the cross section for the fusion-fission reaction 15C + 232Th at energies in the vicinity of the Coulomb barrier and compared it to the yield of the neighboring 14C + 232Th system measured in the same experiment. At sub-barrier energies, an enhancement of the fusion yield by factors of 2-5 was observed for 15C, while the cross sections for 14C match the trends measured for 12,13C.

  19. Observational evidence for a connection between SMBHs and dark matter haloes

    E-Print Network [OSTI]

    Maarten Baes; Herwig Dejonghe; Pieter Buyle; Laura Ferrarese; Gianfranco Gentile

    2004-04-23

    We investigate the relation between circular velocity vc and bulge velocity dispersion sigma in spiral galaxies, based on literature data and new spectroscopic observations. We find a strong, nearly linear vc-sigma correlation with a negligible intrinsic scatter, and a striking agreement with the corresponding relation for elliptical galaxies. The least massive galaxies (sigma < 80 km/s) significantly deviate from this relation. We combine this vc-sigma correlation with the well-known MBH-sigma relation to obtain a tight correlation between circular velocity and supermassive black hole mass, and interpret this as observational evidence for a close link between supermassive black holes and the dark matter haloes in which they presumably formed. Apart from being an important ingredient for theoretical models of galaxy formation and evolution, the relation between MBH and circular velocity has the potential to become an important practical tool in estimating supermassive black hole masses in spiral galaxies.

  20. THE COS-HALOS SURVEY: KECK LRIS AND MAGELLAN MagE OPTICAL SPECTROSCOPY

    SciTech Connect (OSTI)

    Werk, Jessica K.; Prochaska, J. Xavier [UCO/Lick Observatory, University of California, Santa Cruz, CA (United States); Thom, Christopher; Tumlinson, Jason [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD (United States); Tripp, Todd M.; Meiring, Joseph D. [Department of Astronomy, University of Massachusetts, Amherst, MA (United States); O'Meara, John M., E-mail: jwerk@ucolick.org [Department of Chemistry and Physics, Saint Michael's College, Colchester, VT (United States)

    2012-01-01

    We present high signal-to-noise optical spectra for 67 low-redshift (0.1 < z < 0.4) galaxies that lie within close projected distances (5 kpc < {rho} < 150 kpc) of 38 background UV-bright QSOs. The Keck LRIS and Magellan MagE data presented here are part of a survey that aims to construct a statistically sampled map of the physical state and metallicity of gaseous galaxy halos using the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope. We provide a detailed description of the optical data reduction and subsequent spectral analysis that allow us to derive the physical properties of this uniquely data-rich sample of galaxies. The galaxy sample is divided into 38 pre-selected L {approx} L*, z {approx} 0.2 'target' galaxies and 29 'bonus' galaxies that lie in close proximity to the QSO sightlines. We report galaxy spectroscopic redshifts accurate to {+-}30 km s{sup -1}, impact parameters, rest-frame colors, stellar masses, total star formation rates (SFRs), and gas-phase interstellar medium oxygen abundances. When we compare the distribution of these galaxy characteristics to those of the general low-redshift population, we find good agreement. The L {approx} L* galaxies in this sample span a diverse range of color (1.0 < u - r < 3.0), stellar mass (10{sup 9.5} < M/M{sub Sun} < 10{sup 11.5}), and SFRs (0.01-20 M{sub Sun} yr{sup -1}). These optical data, along with the COS UV spectroscopy, comprise the backbone of our efforts to understand how halo gas properties may correlate with their host galaxy properties, and ultimately to uncover the processes that drive gas outflow and/or are influenced by gas inflow.

  1. A population of relic intermediate-mass black holes in the halo of the Milky Way

    SciTech Connect (OSTI)

    Rashkov, Valery; Madau, Piero

    2014-01-10

    If 'seed' central black holes were common in the subgalactic building blocks that merged to form present-day massive galaxies, then relic intermediate-mass black holes (IMBHs) should be present in the Galactic bulge and halo. We use a particle tagging technique to dynamically populate the N-body Via Lactea II high-resolution simulation with black holes, and assess the size, properties, and detectability of the leftover population. The method assigns a black hole to the most tightly bound central particle of each subhalo at infall according to an extrapolation of the M {sub BH}-?{sub *} relation, and self-consistently follows the accretion and disruption of Milky Way progenitor dwarfs and their holes in a cosmological 'live' host from high redshift to today. We show that, depending on the minimum stellar velocity dispersion, ? {sub m}, below which central black holes are assumed to be increasingly rare, as many as ?2000 (? {sub m} = 3 km s{sup –1}) or as few as ?70 (? {sub m} = 12 km s{sup –1}) IMBHs may be left wandering in the halo of the Milky Way today. The fraction of IMBHs forced from their hosts by gravitational recoil is ? 20%. We identify two main Galactic subpopulations, 'naked' IMBHs, whose host subhalos were totally destroyed after infall, and 'clothed' IMBHs residing in dark matter satellites that survived tidal stripping. Naked IMBHs typically constitute 40%-50% of the total and are more centrally concentrated. We show that, in the ? {sub m} = 12 km s{sup –1} scenario, the clusters of tightly bound stars that should accompany naked IMBHs would be fainter than m{sub V} = 16 mag, spatially resolvable, and have proper motions of 0.1-10 mas yr{sup –1}. Their detection may provide an observational tool to constrain the formation history of massive black holes in the early universe.

  2. The Halo, Hot Spots and Jet/Cloud Interaction of PKS 2153--69

    E-Print Network [OSTI]

    A. J. Young; A. S. Wilson; S. J. Tingay; S. Heinz

    2004-12-21

    We report Chandra X-ray Observatory and 1.4 GHz Australian Long Baseline Array (LBA) observations of the radio galaxy PKS 2153--69 and its environment. The Chandra image reveals a roughly spherical halo of hot gas extending out to 30 kpc around PKS 2153--69. Two depressions in the surface brightness of the X-ray halo correspond to the large scale radio lobes, and interpreting these as cavities inflated with radio plasma we infer a jet power of 4x10^42 erg/s. Both radio lobes contain hot spots that are detected by Chandra. In addition, the southern hot spot is detected in the 1.4 GHz LBA observation, providing the highest linear resolution image of a radio lobe hot spot to date. The northern hot spot was not detected in the LBA observation. The radio to X-ray spectra of the hot spots are consistent with a simple power law emission model. The nucleus has an X-ray spectrum typical of a type 1 active galactic nucleus, and the LBA observation shows a one-sided nuclear jet on 0.1" scales. Approximately 10" northeast of the nucleus, X-ray emission is associated with an extra-nuclear cloud. The X-ray emission from the cloud can be divided into two regions, an unresolved western component associated with a knot of radio emission (in a low resolution map), and a spatially extended eastern component aligned with the pc-scale jet and associated with highly ionized optical line-emitting clouds. The X-ray spectrum of the eastern component is very soft (Gamma > 4.0 for a power law model or kT ~0.22 keV for a thermal plasma). The LBA observation did not detect compact radio emission from the extra-nuclear cloud. (Abstract truncated).

  3. Application of Hydrogen Assisted Lean Operation to Natural Gas-Fueled Reciprocating Engines (HALO)

    SciTech Connect (OSTI)

    Chad Smutzer

    2006-01-01

    Two key challenges facing Natural Gas Engines used for cogeneration purposes are spark plug life and high NOx emissions. Using Hydrogen Assisted Lean Operation (HALO), these two keys issues are simultaneously addressed. HALO operation, as demonstrated in this project, allows stable engine operation to be achieved at ultra-lean (relative air/fuel ratios of 2) conditions, which virtually eliminates NOx production. NOx values of 10 ppm (0.07 g/bhp-hr NO) for 8% (LHV H2/LHV CH4) supplementation at an exhaust O2 level of 10% were demonstrated, which is a 98% NOx emissions reduction compared to the leanest unsupplemented operating condition. Spark ignition energy reduction (which will increase ignition system life) was carried out at an oxygen level of 9%, leading to a NOx emission level of 28 ppm (0.13 g/bhp-hr NO). The spark ignition energy reduction testing found that spark energy could be reduced 22% (from 151 mJ supplied to the coil) with 13% (LHV H2/LHV CH4) hydrogen supplementation, and even further reduced 27% with 17% hydrogen supplementation, with no reportable effect on NOx emissions for these conditions and with stable engine torque output. Another important result is that the combustion duration was shown to be only a function of hydrogen supplementation, not a function of ignition energy (until the ignitability limit was reached). The next logical step leading from these promising results is to see how much the spark energy reduction translates into increase in spark plug life, which may be accomplished by durability testing.

  4. Beryllium in Ultra-Lithium-Deficient Halo Stars - The Blue Straggler Connection

    E-Print Network [OSTI]

    Ann Merchant Boesgaard

    2007-05-10

    There are nine metal-deficient stars that have Li abundances well below the Li plateau that is defined by over 100 unevolved stars with temperatures above 5800 K and values of [Fe/H] $<$ $-$1.0. Abundances of Be have been determined for most of these ultra-Li-deficient stars in order to investigate the cause of the Li deficiencies. High-resolution and high signal-to-noise spectra have been obtained in the Be II spectral region near 3130 \\AA for six ultra-Li-deficient stars with the Keck I telescope and its new uv-sensitive CCD on the upgraded HIRES. The spectrum synthesis technique has been used to determine Be abundances. All six stars are found to have Be deficiencies also. Two have measurable - but reduced - Be and four have only upper limits on Be. These results are consistent with the idea that these Li- and Be-deficient stars are analogous to blue stragglers. The stars have undergone mass transfer events (or mergers) which destroy or dilute both Li and Be. The findings cannot be matched by the models that predict that the deficiencies are due to extra-mixing in a subset of halo stars that were initially rapid rotators, with the possible exception of one star, G 139-8. Because the ultra-Li-deficient stars are also Be-deficient, they appear to be genuine outliers in population of halo stars used to determine the value of primordial Li; they no longer have the Li in their atmospheres that was produced in the Big Bang.

  5. Discussion on the energy content of the galactic dark matter Bose-Einstein condensate halo in the Thomas-Fermi approximation

    SciTech Connect (OSTI)

    De Souza, J.C.C.; Pires, M.O.C., E-mail: jose.souza@ufabc.edu.br, E-mail: marcelo.pires@ufabc.edu.br [Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Rua Santa Adélia 166, Santo André, SP, 09210-170 (Brazil)

    2014-03-01

    We show that the galactic dark matter halo, considered composed of an axionlike particles Bose-Einstein condensate [6] trapped by a self-graviting potential [5], may be stable in the Thomas-Fermi approximation since appropriate choices for the dark matter particle mass and scattering length are made. The demonstration is performed by means of the calculation of the potential, kinetic and self-interaction energy terms of a galactic halo described by a Boehmer-Harko density profile. We discuss the validity of the Thomas-Fermi approximation for the halo system, and show that the kinetic energy contribution is indeed negligible.

  6. Dark matter and halo bispectrum in redshift space: theory and applications

    SciTech Connect (OSTI)

    Gil-Marín, Héctor; Percival, Will [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Portsmouth PO1 3FX (United Kingdom); Wagner, Christian [Max-Planck-Institut für Astrophysik, Karl-Schwarzschild Str. 1, 85741 Garching (Germany); Noreña, Jorge [Department of Theoretical Physics and Center for Astroparticle Physics (CAP), 24 quai E. Ansermet, CH-1211 Geneva 4 (Switzerland); Verde, Licia, E-mail: hector.gil@port.ac.uk, E-mail: cwagner@mpa-garching.mpg.de, E-mail: jorge.norena@unige.ch, E-mail: liciaverde@icc.ub.edu, E-mail: will.percival@port.ac.uk [ICREA Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, E-08010 Barcelona (Spain)

    2014-12-01

    We present a phenomenological modification of the standard perturbation theory prediction for the bispectrum in redshift space that allows us to extend the model to mildly non-linear scales over a wide range of redshifts, z?1.5. Our model require 18 free parameters that are fitted to N-body simulations using the shapes k{sub 2}/k{sub 1}=1, 1.5, 2.0, 2.5. We find that we can describe the bispectrum of dark matter particles with ?5% accuracy for k{sub i}?<0.10 h/Mpc at z=0, for k{sub i}?<0.15 h/Mpc at z=0.5, for k{sub i}?<0.17 h/Mpc at z=1.0 and for k{sub i}?<0.20 h/Mpc at z=1.5. For very squeezed triangles with k{sub 1}=k{sub 2}?>0.1 hMpc{sup -1} and k{sub 3}?0.02 hMpc{sup -1}, however, neither SPT nor the proposed fitting formula are able to describe the measured dark matter bispectrum with this accuracy. We show that the fitting formula is sufficiently general that can be applied to other intermediate shapes such as k{sub 2}/k{sub 1}=1.25, 1.75, and 2.25. We also test that the fitting formula is able to describe with similar accuracy the bispectrum of cosmologies with different ?{sub m}, in the range 0.2?< ?{sub m} ?< 0.4, and consequently with different values of the logarithmic grow rate f at z=0, 0.4?< f(z=0) ?< 0.6. We apply this new formula to recover the bias parameters, f and ?{sub 8}, by combining the redshift space power spectrum monopole and quadrupole with the bispectrum monopole for both dark matter particles and haloes. We find that the combination of these three statistics can break the degeneracy between b{sub 1}, f and ?{sub 8}. For dark matter particles the new model can be used to recover f and ?{sub 8} with ?1% accuracy. For dark matter haloes we find that f and ?{sub 8} present larger systematic shifts, ?10%. The systematic offsets arise because of limitations in the modelling of the interplay between bias and redshift space distortions, and represent a limitation as the statistical errors of forthcoming surveys reach this level. Conveniently, we find that these residual systematics are mitigated for combinations of parameters. In particular, the quantity f?{sub 8} is still recovered with ?1% accuracy for the particular halo population and cosmology studied. The improvement on the modelling of the bispectrum presented in this paper will be useful for extracting information from current and future galaxy surveys.

  7. The Milky Way's Circular Velocity Curve to 60 kpc and an Estimate of the Dark Matter Halo Mass from Kinematics of ~2400 SDSS Blue Horizontal Branch Stars

    E-Print Network [OSTI]

    X. -X. Xue; H. -W. Rix; G. Zhao; P. Re Fiorentin; T. Naab; M. Steinmetz; F. C. van den Bosch; T. C. Beers; Y. S. Lee; E. F. Bell; C. Rockosi; B. Yanny; H. Newberg; R. Wilhelm; X. Kang; M. C. Smith; D. P. Schneider

    2008-05-28

    We derive new constraints on the mass of the Milky Way's dark matter halo, based on a set of halo stars from SDSS as kinematic tracers. Our sample comprises 2401 rigorously selected Blue Horizontal-Branch (BHB) halo stars drawn from SDSS DR-6. To interpret these distributions, we compare them to matched mock observations drawn from two different cosmological galaxy formation simulations designed to resemble the Milky Way, which we presume to have an appropriate orbital distribution of halo stars. We then determine which value of $\\rm V_{cir}(r)$ brings the observed distribution into agreement with the corresponding distributions from the simulations. This procedure results in an estimate of the Milky Way's circular velocity curve to $\\sim 60$ kpc, which is found to be slightly falling from the adopted value of $\\rm 220 km s^{-1}$ at the Sun's location, and implies M$(<60 \\rm kpc) = 4.0\\pm 0.7\\times 10^{11}$M$_\\odot$. The radial dependence of $\\rm V_{cir}(r)$, derived in statistically independent bins, is found to be consistent with the expectations from an NFW dark matter halo with the established stellar mass components at its center. If we assume an NFW halo profile of characteristic concentration holds, we can use the observations to estimate the virial mass of the Milky Way's dark matter halo, M$_{\\rm vir}=1.0^{+0.3}_{-0.2} \\times 10^{12}$M$_\\odot$, which is lower than many previous estimates. This estimate implies that nearly 40% of the baryons within the virial radius of the Milky Way's dark matter halo reside in the stellar components of our Galaxy. A value for M$_{\\rm vir}$ of only $\\sim 1\\times10^{12}$M$_\\odot$ also (re-)opens the question of whether all of the Milky Way's satellite galaxies are on bound orbits.

  8. The formation of compact massive self-gravitating discs in metal-free haloes with virial temperatures of ~ 13000-30000 K

    E-Print Network [OSTI]

    John A. Regan; Martin G. Haehnelt

    2008-09-30

    We have used the hydrodynamical AMR code ENZO to investigate the dynamical evolution of the gas at the centre of dark matter haloes with virial velocities of ~ 20 - 30 kms and virial temperatures of ~ 13000-30000 K at z ~ 15 in a cosmological context. The virial temperature of the dark matter haloes is above the threshold where atomic cooling by hydrogen allows the gas to cool and collapse. We neglect cooling by molecular hydrogen and metals, as may be plausible if H_2 cooling is suppressed by a meta-galactic Lyman-Werner background or an internal source of Lyman-Werner photons, and metal enrichment has not progressed very far. The gas in the haloes becomes gravitationally unstable and develops turbulent velocities comparable to the virial velocities of the dark matter haloes. Within a few dynamical times it settles into a nearly isothermal density profile over many decades in radius losing most of its angular momentum in the process. About 0.1 - 1 % of the baryons, at the centre of the dark matter haloes, collapse into a self-gravitating, fat, ellipsoidal, centrifugally supported exponential disc with scale-length of ~ 0.075-0.27 pc and rotation velocities of 25-60 kms. We are able to follow the settling of the gas into centrifugal support and the dynamical evolution of the compact disc in each dark matter halo for a few dynamical times. The dynamical evolution of the gas at the centre of the haloes is complex. In one of the haloes the gas at the centre fragments into a triple system leading to strong tidal perturbations and eventually to the in-fall of a secondary smaller clump into the most massive primary clump. The formation of centrifugally supported self-gravitating massive discs is likely to be an important intermediary stage en route to the formation of a massive black hole seed.

  9. The Role of Primary 16O as a Neutron Poison in AGB stars and Fluorine primary production at Halo Metallicities

    E-Print Network [OSTI]

    Gallino, R; Cristallo, S; Straniero, O

    2010-01-01

    The discovery of a historical bug in the s-post-process AGB code obtained so far by the Torino group forced us to reconsider the role of primary 16O in the 13C-pocket, produced by the 13C(a, n)16O reaction, as important neutron poison for the build up of the s-elements at Halo metallicities. The effect is noticeable only for the highest 13C-pocket efficiencies (cases ST*2 and ST). For Galactic disc metallicities, the bug effect is negligible. A comparative analysis of the neutron poison effect of other primary isotopes (12C, 22Ne and its progenies) is presented. The effect of proton captures, by 14N(n, p)14C, boosts a primary production of Fluorine in Halo AGB stars, with [F/Fe] comparable to [C/Fe], without affecting the s-elements production.

  10. Collisions induced by halo and weakly bound nuclei around the Coulomb barrier: Results at INFN-LNS Catania

    SciTech Connect (OSTI)

    Figuera, Pierpaolo

    2012-10-20

    The study of collisions around the Coulomb barrier induced by halo and/or weakly bound nuclei has been the object of many publications in the last years, since the peculiar structure of such nuclei can strongly affect the reaction dynamics. In this paper we will summarize some results on the above topic obtained by our group at INFN-LNS Catania. Results concerning the study of elastic scattering and different reaction mechanisms in collisions induced by the halo nuclei {sup 11}Be and {sup 6}He and by the weakly bound stable nuclei {sup 6,7}Li on a {sup 64}Zn target, at energies around the Coulomb barrier, will be presented. The conclusions of our studies will be compared with the ones of other authors, in order to show if clear systematic conclusions can be drawn from the different papers published in the literature so far.

  11. TWO DISTANT HALO VELOCITY GROUPS DISCOVERED BY THE PALOMAR TRANSIENT FACTORY

    SciTech Connect (OSTI)

    Sesar, Branimir; Cohen, Judith G.; Levitan, David; Kirby, Evan N.; Kulkarni, Shrinivas R.; Prince, Thomas A.; Grillmair, Carl J.; Laher, Russ R.; Surace, Jason A.; Juric, Mario; Ofek, Eran O.

    2012-08-20

    We report the discovery of two new halo velocity groups (Cancer groups A and B) traced by eight distant RR Lyrae stars and observed by the Palomar Transient Factory survey at R.A. {approx} 129 Degree-Sign , decl. {approx} 20 Degree-Sign (l {approx} 205 Degree-Sign , b {approx} 32 Degree-Sign ). Located at 92 kpc from the Galactic center (86 kpc from the Sun), these are some of the most distant substructures in the Galactic halo known to date. Follow-up spectroscopic observations with the Palomar Observatory 5.1 m Hale telescope and W. M. Keck Observatory 10 m Keck I telescope indicate that the two groups are moving away from the Galaxy at v-bar{sub gsr}{sup A} = 78.0{+-}5.6 km s{sup -1} (Cancer group A) and v-bar{sub gsr}{sup B} = 16.3{+-}7.1 km s{sup -1} (Cancer group B). The groups have velocity dispersions of {sigma}{sub v{sub g{sub s{sub r}{sup A}}}} = 12.4{+-}5.0 km s{sup -1} and {sigma}B{sub v{sub g{sub s{sub r}{sup B}}}} =14.9{+-}6.2 km s{sup -1} and are spatially extended (about several kpc), making it very unlikely that they are bound systems, and more likely to be debris of tidally disrupted dwarf galaxies or globular clusters. Both groups are metal-poor (median metallicities of [Fe/H]{sup A} = -1.6 dex and [Fe/H]{sup B} = -2.1 dex) and have a somewhat uncertain (due to small sample size) metallicity dispersion of {approx}0.4 dex, suggesting dwarf galaxies as progenitors. Two additional RR Lyrae stars with velocities consistent with those of the Cancer groups have been observed {approx}25 Degree-Sign east, suggesting possible extension of the groups in that direction.

  12. Mapping compound cosmic telescopes containing multiple projected cluster-scale halos

    SciTech Connect (OSTI)

    Ammons, S. Mark; Wong, Kenneth C.; Zabludoff, Ann I.; Keeton, Charles R. E-mail: kwong@as.arizona.edu E-mail: keeton@physics.rutgers.edu

    2014-01-20

    Lines of sight with multiple projected cluster-scale gravitational lenses have high total masses and complex lens plane interactions that can boost the area of magnification, or étendue, making detection of faint background sources more likely than elsewhere. To identify these new 'compound' cosmic telescopes, we have found directions in the sky with the highest integrated mass densities, as traced by the projected concentrations of luminous red galaxies (LRGs). We use new galaxy spectroscopy to derive preliminary magnification maps for two such lines of sight with total mass exceeding ?3 × 10{sup 15} M {sub ?}. From 1151 MMT Hectospec spectra of galaxies down to i {sub AB} = 21.2, we identify two to three group- and cluster-scale halos in each beam. These are well traced by LRGs. The majority of the mass in beam J085007.6+360428 (0850) is contributed by Zwicky 1953, a massive cluster at z = 0.3774, whereas beam J130657.5+463219 (1306) is composed of three halos with virial masses of 6 × 10{sup 14}-2 × 10{sup 15} M {sub ?}, one of which is A1682. The magnification maps derived from our mass models based on spectroscopy and Sloan Digital Sky Survey photometry alone display substantial étendue: the 68% confidence bands on the lens plane area with magnification exceeding 10 for a source plane of z{sub s} = 10 are [1.2, 3.8] arcmin{sup 2} for 0850 and [2.3, 6.7] arcmin{sup 2} for 1306. In deep Subaru Suprime-Cam imaging of beam 0850, we serendipitously discover a candidate multiply imaged V-dropout source at z {sub phot} = 5.03. The location of the candidate multiply imaged arcs is consistent with the critical curves for a source plane of z = 5.03 predicted by our mass model. Incorporating the position of the candidate multiply imaged galaxy as a constraint on the critical curve location in 0850 narrows the 68% confidence band on the lens plane area with ? > 10 and z{sub s} = 10 to [1.8, 4.2] arcmin{sup 2}, an étendue range comparable to that of MACS 0717+3745 and El Gordo, two of the most powerful single cluster lenses known. The significant lensing power of our beams makes them powerful probes of reionization and galaxy formation in the early universe.

  13. The PAndAS field of streams: Stellar structures in the milky way halo toward Andromeda and Triangulum

    SciTech Connect (OSTI)

    Martin, Nicolas F.; Ibata, Rodrigo A.; Rich, R. Michael; Collins, Michelle L. M.; Fardal, Mark A.; Irwin, Michael J.; Lewis, Geraint F.; Bate, Nicholas F.; Conn, Anthony R.; McConnachie, Alan W.; Babul, Arif; Navarro, Julio F.; Chapman, Scott C.; Crnojevi?, Denija; Ferguson, Annette M. N.; Peñarrubia, Jorge; Mackey, A. Dougal; Tanvir, Nial T.; Valls-Gabaud, David

    2014-05-20

    We reveal the highly structured nature of the Milky Way (MW) stellar halo within the footprint of the Pan-Andromeda Archaeological Survey (PAndAS) photometric survey from blue main sequence (MS) and MS turn-off stars. We map no fewer than five stellar structures within a heliocentric range of ?5-30 kpc. Some of these are known (the Monoceros Ring, the Pisces/Triangulum globular cluster stream), but we also uncover three well-defined stellar structures that could be, at least partly, responsible for the so-called Triangulum/Andromeda and Triangulum/Andromeda 2 features. In particular, we trace a new faint stellar stream located at a heliocentric distance of ?17 kpc. With a surface brightness of ? {sub V} ? 32-32.5 mag arcsec{sup –2}, it follows an orbit that is almost parallel to the Galactic plane north of M31 and has so far eluded surveys of the MW halo as these tend to steer away from regions dominated by the Galactic disk. Investigating our follow-up spectroscopic observations of PAndAS, we serendipitously uncover a radial velocity signature from stars that have colors and magnitudes compatible with the stream. From the velocity of eight likely member stars, we show that this stellar structure is dynamically cold, with an unresolved velocity dispersion that is lower than 7.1 km s{sup –1} at the 90% confidence level. Along with the width of the stream (300-650 pc), its dynamics point to a dwarf-galaxy-accretion origin. The numerous stellar structures we can map in the MW stellar halo between 5 and 30 kpc and their varying morphology is a testament to the complex nature of the stellar halo at these intermediate distances.

  14. Chemical Evolution of the Galactic Halo through Supernova-Induced Star Formation and Its Implication for Population III Stars

    E-Print Network [OSTI]

    Takuji Tsujimoto; Toshikazu Shigeyama; Yuzuru Yoshii

    1999-05-06

    A model for Galactic chemical evolution, driven by supernova-induced star formation, is formulated and used to examine the nature of the Galactic halo at early epochs. In this model, new stars are formed following each supernova event, thus their abundance pattern is determined by the combination of heavy elements ejected from the supernova itself and those elements which are already present in the interstellar gas swept up by the supernova remnant. The end result is a prediction of large scatter in the abundance ratios among low-metallicity stars, reflecting a different nucleosynthesis yield for each Type II supernova with a different progenitor mass. Formation of new stars is terminated when supernova remnants sweep up too little gas to form shells. We show from calculations based on the above scenario that (i) the observed [Fe/H] distribution for the Galactic halo field stars can be reproduced without effectively decreasing the heavy-element yields from Type II supernovae by some manipulation required by previous models (e.g., via mass loss from the early Galaxy, or later mixing with ``pristine'' hydrogen clouds), (ii) the large observed scatter in the abundance ratio [Eu/Fe] for the most metal-poor stars can also be reproduced, and (iii) the frequency distribution of stars in the [Eu/Fe]-[Fe/H] plane can be predicted. Our model suggests that the probability of identifying essentially metal-free stars (Population III) in the local halo is around one in 10^{3-4}, provided that star formation in the halo is confined to individual gas clouds with mass of 10^{6-7} Msun and that the initial mass function of metal-free stars is not significantly different from the Salpeter mass function.

  15. The Impact of Baryonic Physics on the Structure of Dark Matter Halos: the View from the FIRE Cosmological Simulations

    E-Print Network [OSTI]

    Chan, T K; Oñorbe, J; Hopkins, P F; Muratov, A L; Faucher-Giguère, C -A; Quataert, E

    2015-01-01

    We study the distribution of cold dark matter (CDM) in cosmological zoom-in simulations from the Feedback in Realistic Environments (FIRE) project, for a range of halo mass (10^9-10^12 Msun) and stellar mass (10^4-10^11 Msun). The FIRE simulations incorporate explicit stellar feedback within the multi-phase ISM. We find that stellar feedback, without any "fine-tuned" parameters, can greatly alleviate small-scale problems in CDM. Feedback causes bursts of star formation and outflows, altering the DM distribution. As a result, the inner slope of the DM halo profile "alpha" shows a strong mass dependence: profiles are shallow at M_h ~ 10^10-10^11 Msun and steepen at higher/lower masses. The resulting core sizes and slopes are consistent with observations. This is broadly consistent with previous work using simpler feedback schemes, but we find steeper mass dependence of "alpha," and relatively late growth of cores. Because the star formation efficiency is strongly halo mass dependent, a rapid change in the centr...

  16. Halo expansion in cosmological hydro simulations: towards a baryonic solution of the cusp/core problem in massive spirals

    E-Print Network [OSTI]

    Maccio', Andrea V; Brook, Chris B; Wadsley, James; Couchman, H M P; Shen, Sijing; Gibson, Brad K; Quinn, Tom

    2011-01-01

    A clear prediction of the Cold Dark Matter model is the existence of cuspy dark matter halo density profiles on all mass scales. This is not in agreement with the observed rotation curves of spiral galaxies, challenging on small scales the otherwise successful CDM paradigm. In this work we employ high resolution cosmological hydro-dynamical simulations to study the effects of dissipative processes on the inner distribution of dark matter in Milky-Way like objects (M~1e12 Msun). Our simulations include supernova feedback, and the effects of the radiation pressure of massive stars before they explode as supernovae. The increased stellar feedback results in the expansion of the dark matter halo instead of contraction with respect to N-body simulations. Baryons are able to erase the dark matter cuspy distribution creating a flat, cored, dark matter density profile in the central several kpc of a massive Milky-Way like halo. The profile is well fit by a Burkert profile, with fitting parameters consistent with the ...

  17. Detection of a distinct metal-poor stellar halo in the early-type galaxy NGC 3115

    E-Print Network [OSTI]

    Peacock, Mark B; Romanowsky, Aaron J; Brodie, Jean P

    2014-01-01

    We present the resolved stellar populations in the inner and outer halo of the nearby lenticular galaxy NGC~3115. Using deep HST observations, we analyze stars two magnitudes fainter than the tip of the red giant branch (TRGB). We study three fields along the minor axis of this galaxy, 19, 37 and 54 kpc from its center -- corresponding to 7, 14, 21 effective radii (r_{e}). Even at these large galactocentric distances, all of the fields are dominated by a relatively enriched population, with the main peak in the metallicity distribution decreasing with radius from [Z/H] ~ -0.5 to -0.65. The fraction of metal-poor stars ([Z/H] < -0.95) increases from 17%, at 16-37 kpc, to 28%, at ~54 kpc. We observe a distinct low metallicity population (peaked at [Z/H] ~ -1.3 and with total mass 2*10^{10}M_{\\odot} ~ 14% of the galaxy's stellar mass) and argue that this represents the detection of an underlying low metallicity stellar halo. Such halos are generally predicted by galaxy formation theories and have been observe...

  18. Quantifying the heart of darkness with GHALO - a multi-billion particle simulation of our galactic halo

    E-Print Network [OSTI]

    Joachim Stadel; Doug Potter; Ben Moore; Jürg Diemand; Piero Madau; Marcel Zemp; Michael Kuhlen; Vicent Quilis

    2008-08-22

    We perform a series of simulations of a Galactic mass dark matter halo at different resolutions, our largest uses over three billion particles and has a mass resolution of 1000 M_sun. We quantify the structural properties of the inner dark matter distribution and study how they depend on numerical resolution. We can measure the density profile to a distance of 120 pc (0.05% of R_vir) where the logarithmic slope is -0.8 and -1.4 at (0.5% of R_vir). We propose a new two parameter fitting function that has a linearly varying logarithmic density gradient which fits the GHALO and VL2 density profiles extremely well. Convergence in the density profile and the halo shape scales as N^(-1/3), but the shape converges at a radius three times larger at which point the halo becomes more spherical due to numerical resolution. The six dimensional phase-space profile is dominated by the presence of the substructures and does not follow a power law, except in the smooth under-resolved inner few kpc.

  19. The Metallicity Distribution Function of the Halo of the Milky Way

    E-Print Network [OSTI]

    Timothy C. Beers; Norbert Christlieb; John E. Norris; Michael S. Bessell; Ronald Wilhelm; Carlos Allende Prieto; Brian Yanny; Constance Rockosi; Heidi Jo Newberg; Silvia Rossi; Young Sun Lee

    2005-08-19

    We report on the distribution of metallicities, [Fe/H], for very metal-poor stars in the halo of the Galaxy. Although the primary information on the nature of the Metallicity Distribution Function (MDF) is obtained from the two major recent surveys for metal-poor stars, the HK survey of Beers and collaborators, and the Hamburg/ESO Survey of Christlieb and collaborators, we also discuss the MDF derived from the publicly available database of stellar spectra and photometry contained in the third data release of the Sloan Digital Sky Survey (SDSS DR-3). Even though the SDSS was not originally planned as a stellar survey, significant numbers of stars have been observed to date -- DR-3 contains spectroscopy for over 70,000 stars, at least half of which are suitable for abundance determinations. There are as many very metal-poor ([Fe/H] < -2.0) stars in DR-3 as have been obtained from all previous survey efforts combined. We also discuss prospects for significant expansion of the list of metal-poor stars to be obtained from the recently funded extension of the SDSS, which includes the project SEGUE: Sloan Extension for Galactic Understanding and Exploration.

  20. Power-laws and Non-Power-laws in Dark Matter Halos

    E-Print Network [OSTI]

    R. N. Henriksen

    2006-09-05

    Simulated dark matter profiles are often modelled as a `NFW' density profile rather than a single power law. Recently, attention has turned to the rather rigorous power-law behaviour exhibited by the `pseudo phase-space density' of the dark matter halo, which is defined dimensionally in terms of the local density and velocity dispersion of the dark matter particles. The non-power-law behaviour of the density profile is generally taken to exclude simple scale-free, in-fall models; however the power-law behaviour of the `pseudo-density' is a counter indication. We argue in this paper that both behaviours may be at least qualitatively understood in terms of a dynamically evolving self-similarity, rather than the form for self-similar infall that is fixed by cosmological initial conditions. The evolution is likely due to collective relaxation such as that provided by the radial-orbit instability on large scales. We deduce, from a distribution function given by first order coarse-graining, both the NFW-type density profile and the power-law pseudo-density profile. The results are not greatly sensitive to variation about 3 in the power of the velocity dispersion used in the definition of the phase space pseudo-density. We suggest that the power 2 may create the more physical quantity, whose deviations from a power-law are a diagnostic of incomplete relaxation.

  1. Channeling and Volume Reflection Based Crystal Collimation of Tevatron Circulating Beam Halo (T-980)

    SciTech Connect (OSTI)

    Shiltsev, V.; Annala, G.; Drozhdin, A.; Johnson, T.; Legan, A.; Mokhov, N.; Reilly, R.; Still, D.; Tesarek, R.; Zagel, J.; Peggs, S.; /Brookhaven /CERN /Serpukhov, IHEP /INFN, Ferrara /PNPI, CSTD

    2010-05-01

    The T980 crystal collimation experiment is underway at the Tevatron to determine if this technique could increase 980 GeV beam-halo collimation efficiency at high-energy hadron colliders such as the Tevatron and the LHC. T980 also studies various crystal types and parameters. The setup has been substantially enhanced during the Summer 2009 shutdown by installing a new O-shaped crystal in the horizontal goniometer, as well as adding a vertical goniometer with two alternating crystals (O-shaped and multi-strip) and additional beam diagnostics. First measurements with the new system are quite encouraging, with channeled and volume-reflected beams observed on the secondary collimators as predicted. Investigation of crystal collimation efficiencies with crystals in volume reflection and channeling modes are described in comparison with an amorphous primary collimator. Results on the system performance are presented for the end-of-store studies and for entire collider stores. The first investigation of colliding beam collimation simultaneously using crystals in both the vertical and horizontal plane has been made in the regime with horizontally channeled and vertically volume-reflected beams. Planning is underway for significant hardware improvements during the FY10 summer shutdown and for dedicated studies during the final year of Tevatron operation and also for a 'post-collider beam physics running' period.

  2. Brightest Cluster Galaxies in the Extended GMRT radio halo cluster sample. Radio properties and cluster dynamics

    E-Print Network [OSTI]

    Kale, Ruta; Cassano, Rossella; Giacintucci, Simona; Bardelli, sandro; Dallacasa, Daniele; Zucca, Elena

    2015-01-01

    Brightest Cluster Galaxies (BCGs) show exceptional properties over the whole electromagnetic spectrum. Their special location at the centres of galaxy clusters raises the question of the role of the environment on their radio properties. To decouple the effect of the galaxy mass and of the environment in their statistical radio properties, we investigate the possible dependence of the occurrence of radio loudness and of the fractional radio luminosity function on the dynamical state of the hosting cluster. We studied the radio properties of the BCGs in the Extended GMRT Radio Halo Survey (EGRHS). We obtained a statistical sample of 59 BCGs, which was divided into two classes, depending on the dynamical state of the host cluster, i.e. merging (M) and relaxed (R). Among the 59 BCGs, 28 are radio-loud, and 31 are radio--quiet. The radio-loud sources are located favourably located in relaxed clusters (71\\%), while the reverse is true for the radio-quiet BCGs, mostly located in merging systems (81\\%). The fraction...

  3. On the occurrence of Radio Halos in galaxy clusters - Insight from a mass-selected sample

    E-Print Network [OSTI]

    Cuciti, V; Brunetti, G; Dallacasa, D; Kale, R; Ettori, S; Venturi, T

    2015-01-01

    Giant radio halos (RH) are diffuse Mpc-scale synchrotron sources detected in a fraction of massive and merging galaxy clusters. An unbiased study of the statistical properties of RHs is crucial to constrain their origin and evolution. We aim at investigating the occurrence of RHs and its dependence on the cluster mass in a SZ-selected sample of galaxy clusters, which is as close as possible to be a mass-selected sample. Moreover, we analyse the connection between RHs and merging clusters. We select from the Planck SZ catalogue (Planck Collaboration XXIX 2014) clusters with $M\\geq 6\\times10^{14} M_\\odot$ at z=0.08-0.33 and we search for the presence of RHs using the NVSS for z<0.2 and the GMRT RH survey (GRHS, Venturi et al. 2007, 2008) and its extension (EGRHS, Kale et al. 2013, 2015) for 0.2

  4. A Survey of UV Bright Sources Behind the Halo of M31

    E-Print Network [OSTI]

    Fittingoff, Andrew; Kalirai, Jasonjot S; Strader, Jay; Guhathakurta, Puragra; Kaplan, Kyle F

    2009-01-01

    We have performed a wide-area ultraviolet (UV) imaging survey using the GALaxy Evolution eXplorer (GALEX) to search for bright, point-like UV sources behind M31's extended halo. Our survey consisted of 46 pointings covering an effective area of ~50 deg^2, in both the far-UV and near-UV channels. We combined these data with optical R-band observations acquired with the WIYN Mosaic-1 imager on the Kitt Peak National Observatory 0.9m WIYN telescope. An analysis of the brightness and colors of sources matched between our photometric catalogs yielded ~100 UV-bright quasar candidates. We have obtained discovery spectra for 76 of these targets with the Kast spectrometer on the Lick 3m telescope and confirm 30 active galactic nuclei and quasars, 29 galaxies at z > 0.02 including several early-type systems, 16 Galactic stars (hot main-sequence stars), and one featureless source previously identified as a BL Lac object. Future UV spectroscopy of the brightest targets with the Cosmic Origins Spectrograph on the Hubble S...

  5. Presumable European aurorae in the mid AD 770s were halo displays

    E-Print Network [OSTI]

    Neuhaeuser, Dagmar

    2015-01-01

    The interpretation of the strong 14-C variation around AD 775 as one (or several) solar super-flare(s) by, e.g., Usoskin et al. (2013) is based on alleged aurora sightings in the mid AD 770s in Europe: A "red cross/crucifix" in AD 773/4/6 from the Anglo-Saxon Chronicle, "inflamed shields" in AD 776 (both listed in the aurora catalogue of Link 1962), and "riders on white horses" in AD 773 (newly proposed as aurora in Usoskin et al. 2013), the two latter from the Royal Frankish Annals. We discuss the reports about these three sightings in detail here. We can show that all three were halo displays: The "red cross" or "crucifix" is formed by the horizontal arc and a vertical pillar of light (either with the Sun during sunset or with the moon after sunset); the "inflamed shields" and the "riders on white horses" were both two mock suns, especially the latter narrated in form of a Christian adaptation of the antique dioscuri motive. While the latter event took place early in AD 774 (dated AD 773 in Usoskin et al. 2...

  6. The clustering of merging star-forming haloes: dust emission as high frequency arcminute CMB foreground

    E-Print Network [OSTI]

    Righi, M; Sunyaev, R

    2007-01-01

    Future observations of CMB anisotropies will be able to probe high multipole regions of the angular power spectrum, corresponding to a resolution of a few arcminutes. Dust emission from merging haloes is one of the foregrounds that will affect such very small scales. We estimate the contribution to CMB angular fluctuations from objects which are bright in the sub-millimeter band due to intense star formation bursts following merging episodes. We also consider the effect of the intergalactic dust expelled from galaxies by strong winds and AGN activity. We base our approach on the Lacey-Cole merger model and on the Kennicutt relation which connects the star formation rate in galaxies with their infrared luminosity. We set the free parameters of the model in order to not exceed the SCUBA source counts, the Madau plot of star formation rate in the universe and COBE/FIRAS data on the intensity of the sub-millimeter cosmic background radiation. We show that the angular power spectrum arising from the distribution o...

  7. Tidal Stream Morphology as an Indicator of Dark Matter Halo Geometry: the Case of Palomar 5

    E-Print Network [OSTI]

    Pearson, Sarah; Johnston, Kathryn V; Price-Whelan, Adrian M

    2014-01-01

    This paper presents an example where the morphology of a single stellar stream can be used to rule out a specific galactic potential form without the need for velocity information. We investigate the globular cluster Palomar5 (Pal 5), which is tidally disrupting into a cold, thin stream mapped over 22 degrees on the sky with a typical width of 0.7 degrees. We generate models of this stream by fixing Pal 5's present-day position, distance and radial velocity via observations, while allowing its proper motion to vary. In a spherical dark matter halo we easily find models that fit the observed morphology. However, no plausible Pal 5 model could be found in the triaxial potential of Law & Majewski (2010), which has been proposed to explain the properties of the Sagittarius stream. In this case, the long, thin and curved morphology of the Pal5 stream alone can be used to rule out such a potential configuration. Pal 5 like streams in this potential are either too straight, missing the curvature of the observati...

  8. Lithium abundance in a turnoff halo star on an extreme orbit

    E-Print Network [OSTI]

    Spite, Monique; Caffau, Elisabetta; Bonifacio, Piercarlo

    2015-01-01

    The lithium abundance in turnoff stars of the old population of our Galaxy is remarkably constant in the metallicity interval -2.8\\textless{}[Fe/H] \\textless{}-2.0, defining a plateau. The Li abundance of these turnoff stars is clearly lower than the abundance predicted by the primordial nucleosynthesis in the frame of the standard Big Bang nucleosynthesis. Different scenarios have been proposed for explaining this discrepancy, along with the very low scatter of the lithium abundance around the plateau. The recently identified very high velocity star, WISE J072543.88-235119.7 appears to belong to the old Galactic population, and appears to be an extreme halo star on a bound, retrograde Galactic orbit. In this paper, we study the abundance ratios and, in particular the lithium abundance, in this star. The available spectra (ESO-Very Large Telescope) are analyzed and the abundances of Li, C, Na, Mg, Al, Si, Ca, Sc, Ti, Cr, Mn, Fe, Co, Ni, Sr and Ba are determined.The abundance ratios in WISE J072543.88-235119.7...

  9. Qualitative and analytical results of the bifurcation thresholds to halo orbits

    E-Print Network [OSTI]

    Sara Bucciarelli; Marta Ceccaroni; Alessandra Celletti; Giuseppe Pucacco

    2015-02-01

    We study the dynamics in the neighborhood of the collinear Lagrangian points in the spatial, circular, restricted three--body problem. We consider the case in which one of the primaries is a radiating body and the other is oblate (although the latter is a minor effect). Beside having an intrinsic mathematical interest, this model is particularly suited for the description of a mission of a spacecraft (e.g., a solar sail) to an asteroid. The aim of our study is to investigate the occurrence of bifurcations to halo orbits, which take place as the energy level is varied. The estimate of the bifurcation thresholds is performed by analytical and numerical methods: we find a remarkable agreement between the two approaches. As a side result, we also evaluate the influence of the different parameters, most notably the solar radiation pressure coefficient, on the dynamical behavior of the model. To perform the analytical and numerical computations, we start by implementing a center manifold reduction. Next, we estimate the bifurcation values using qualitative techniques (e.g. Poincar\\'e surfaces, frequency analysis, FLIs). Concerning the analytical approach, following \\cite{CPS} we implement a resonant normal form, we transform to suitable action-angle variables and we introduce a detuning parameter measuring the displacement from the synchronous resonance. The bifurcation thresholds are then determined as series expansions in the detuning. Three concrete examples are considered and we find in all cases a very good agreement between the analytical and numerical results.

  10. Mass segregation in the diffuse outer-halo globular cluster Palomar 14

    E-Print Network [OSTI]

    Frank, Matthias J; Küpper, Andreas H W

    2013-01-01

    We present an analysis of the radial dependence of the stellar mass function in the diffuse outer-halo globular cluster Palomar 14. Using archival HST/WFPC2 data of the cluster's central 39 pc (corresponding to ~0.85*r_h) we find that the mass function in the mass range of 0.55 to 0.85 solar masses is well approximated by a power-law at all radii. The mass function steepens with increasing radius, from a shallow power-law slope of 0.66+/-0.32 in the cluster's centre to a slope of 1.61+/-0.33 beyond the core radius, showing that the cluster is mass-segregated. This is seemingly in conflict with its long present-day half-mass relaxation time of ~20 Gyr, and with the recent finding by Beccari et al. (2011), who interpret the cluster's non-concentrated population of blue straggler stars as evidence that dynamical segregation has not affected the cluster yet. We discuss this apparent conflict and argue that the cluster must have either formed with primordial mass segregation, or that its relaxation time scale must...

  11. Computation of stationary 3D halo currents in fusion devices with accuracy control

    SciTech Connect (OSTI)

    Bettini, Paolo, E-mail: paolo.bettini@unipd.it [Università degli Studi di Padova, Dipartimento di Ingegneria Industriale (DII), Via Gradenigo 6/A, 35131 Padova (Italy); Consorzio RFX, C.so Stati Uniti 4, 35127 Padova (Italy); Specogna, Ruben, E-mail: ruben.specogna@uniud.it [Università degli Studi di Udine, Dipartimento di Ingegneria Elettrica, Gestionale e Meccanica (DIEGM), Via delle Scienze 206, I-33100 Udine (Italy)

    2014-09-15

    This paper addresses the calculation of the resistive distribution of halo currents in three-dimensional structures of large magnetic confinement fusion machines. A Neumann electrokinetic problem is solved on a geometry so complicated that complementarity is used to monitor the discretization error. An irrotational electric field is obtained by a geometric formulation based on the electric scalar potential, whereas three geometric formulations are compared to obtain a solenoidal current density: a formulation based on the electric vector potential and two geometric formulations inspired from mixed and mixed-hybrid Finite Elements. The electric vector potential formulation is usually considered impractical since an enormous computing power is wasted by the topological pre-processing it requires. To solve this challenging problem, we present novel algorithms based on lazy cohomology generators that enable to save orders of magnitude computational time with respect to all other state-of-the-art solutions proposed in literature. Believing that our results are useful in other fields of scientific computing, the proposed algorithm is presented as a detailed pseudocode in such a way that it can be easily implemented.

  12. Constraining the mSUGRA (minimal supergravity) parameter space using the entropy of dark matter halos

    SciTech Connect (OSTI)

    Nunez, Dario; Zavala, Jesus; Nellen, Lukas; Sussman, Roberto A; Cabral-Rosetti, Luis G; Mondragon, Myriam E-mail: jzavala@nucleares.unam.mx E-mail: lukas@nucleares.unam.mx E-mail: lgcabral@ciidet.edu.mx; Collaboration: For the Instituto Avanzado de Cosmologia, IAC

    2008-05-15

    We derive an expression for the entropy of a dark matter halo described using a Navarro-Frenk-White model with a core. The comparison of this entropy with that of dark matter in the freeze-out era allows us to constrain the parameter space in mSUGRA models. Moreover, combining these constraints with the ones obtained from the usual abundance criterion and demanding that these criteria be consistent with the 2{sigma} bounds for the abundance of dark matter: 0.112{<=}{Omega}{sub DM}h{sup 2}{<=}0.122, we are able to clearly identify validity regions among the values of tan{beta}, which is one of the parameters of the mSUGRA model. We found that for the regions of the parameter space explored, small values of tan{beta} are not favored; only for tan {beta} Asymptotically-Equal-To 50 are the two criteria significantly consistent. In the region where the two criteria are consistent we also found a lower bound for the neutralino mass, m{sub {chi}}{>=}141 GeV.

  13. Pathways to massive black holes and compact star clusters in pre-galactic dark matter haloes with virial temperatures > 10000K

    E-Print Network [OSTI]

    John A. Regan; Martin G. Haehnelt

    2008-10-15

    Large dynamic range numerical simulations of atomic cooling driven collapse of gas in pre-galactic DM haloes with T_vir ~ 10000 K show that the gas loses 90% and more of its angular momentum before rotational support sets in. In a fraction of these haloes where the metallicity is low and UV radiation suppresses H_2 cooling, conditions are thus very favourable for the rapid build-up of massive black holes. Depending on the progression of metal enrichment, the continued suppression of H_2 cooling by external and internal UV radiation and the ability to trap the entropy produced by the release of gravitational energy, the gas at the centre of the halo is expected to form a supermassive star, a stellar-mass black hole accreting at super-Eddington accretion rates or a compact star-cluster undergoing collisional run-away of massive stars at its centre. In all three cases a massive black hole of initially modest mass finds itself at the center of a rapid inflow of gas with inflow rates of ~ 1 M_solar\\yr. The massive black hole will thus grow quickly to a mass of 10^5 to 10^6 M_solar until further inflow is halted either by consumption of gas by star formation or by the increasing energy and momentum feedback from the growing massive black hole. Conditions for the formation of massive seed black holes in this way are most favourable in haloes with T_vir ~ 15000 K and V_vir ~ 20 km\\s with less massive haloes not allowing collapse of gas by atomic cooling and more massive haloes being more prone to fragmentation. This should imprint a characteristic mass on the mass spectrum of an early population of massive black hole seeds in pre-galactic haloes which will later grow into the observed population of supermassive black holes in galactic bulges.

  14. CALiPER Snapshot Report: Light Bulbs

    SciTech Connect (OSTI)

    2013-10-01

    Snapshot reports use data from DOE's LED Lighting Facts product list to compare the LED performance to standard technologies, and are designed to help lighting retailers, distributors, designers, utilities, energy efficiency program sponsors, and other stakeholders understand the current state of the LED market and its trajectory.

  15. A budget and accounting of metals at z ? 0: Results from the COS-Halos survey

    SciTech Connect (OSTI)

    Peeples, Molly S. [Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, CA (United States); Werk, Jessica K.; Prochaska, J. Xavier [UCO/Lick Observatory, University of California, Santa Cruz, CA (United States); Tumlinson, Jason [Space Telescope Science Institute, Baltimore, MD (United States); Oppenheimer, Benjamin D. [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO (United States); Katz, Neal [Department of Astronomy, University of Massachusetts, Amherst, MA (United States); Weinberg, David H., E-mail: molly@stsci.edu [Department of Astronomy, The Ohio State University, Columbus, OH (United States)

    2014-05-01

    We present a budget and accounting of metals in and around star-forming galaxies at z ? 0. We combine empirically derived star formation histories with updated supernova and asymptotic giant branch yields and rates to estimate the total mass of metals produced by galaxies with present-day stellar mass of 10{sup 9.3}-10{sup 11.6} M{sub ?}. On the accounting side of the ledger, we show that a surprisingly constant 20%-25% mass fraction of produced metals remain in galaxies' stars, interstellar gas and interstellar dust, with little dependence of this fraction on the galaxy stellar mass (omitting those metals immediately locked up in remnants). Thus, the bulk of metals are outside of galaxies, produced in the progenitors of today's L* galaxies. The COS-Halos survey is uniquely able to measure the mass of metals in the circumgalactic medium (CGM, to impact parameters of <150 kpc) of low-redshift ?L* galaxies. Using these data, we map the distribution of CGM metals as traced by both the highly ionized O VI ion and a suite of low-ionization species; combined with constraints on circumgalactic dust and hotter X-ray emitting gas out to similar impact parameters, we show that ?40% of metals produced by M {sub *} ? 10{sup 10} M{sub ?} galaxies can be easily accounted for out to 150 kpc. With the current data, we cannot rule out a constant mass of metals within this fixed physical radius. This census provides a crucial boundary condition for the eventual fate of metals in galaxy evolution models.

  16. THE BIZARRE CHEMICAL INVENTORY OF NGC 2419, AN EXTREME OUTER HALO GLOBULAR CLUSTER

    SciTech Connect (OSTI)

    Cohen, Judith G.; Kirby, Evan N. E-mail: enk@astro.caltech.edu

    2012-11-20

    We present new Keck/HIRES observations of six red giants in the globular cluster (GC) NGC 2419. Although the cluster is among the most distant and most luminous in the Milky Way, it was considered chemically ordinary until very recently. Our previous work showed that the near-infrared Ca II triplet line strength varied more than expected for a chemically homogeneous cluster, and that at least one star had unusual abundances of Mg and K. Here, we confirm that NGC 2419 harbors a population of stars, comprising about one-third of its mass, that is depleted in Mg by a factor of eight and enhanced in K by a factor of six with respect to the Mg-normal population. Although the majority, Mg-normal population appears to have a chemical abundance pattern indistinguishable from ordinary, inner-halo GCs, the Mg-poor population exhibits dispersions of several elements. The abundances of K and Sc are strongly anti-correlated with Mg, and some other elements (Si and Ca among others) are weakly anti-correlated with Mg. These abundance patterns suggest that the different populations of NGC 2419 sample the ejecta of diverse supernovae in addition to asymptotic giant branch ejecta. However, the abundances of Fe-peak elements except Sc show no star-to-star variation. We find no nucleosynthetic source that satisfactorily explains all of the abundance variations in this cluster. Because NGC 2419 appears like no other GC, we reiterate our previous suggestion that it is not a GC at all, but rather the core of an accreted dwarf galaxy.

  17. Integral Field Unit Observations of NGC 4302: Kinematics of the Diffuse Ionized Gas Halo

    E-Print Network [OSTI]

    George H. Heald; Richard J. Rand; Robert A. Benjamin; Matthew A. Bershady

    2007-03-13

    We present moderate resolution spectroscopy of extraplanar diffuse ionized gas (EDIG) emission in the edge-on spiral galaxy NGC 4302. The spectra were obtained with the SparsePak integral field unit (IFU) at the WIYN Observatory. The spectra are used to construct position-velocity (PV) diagrams at several ranges of heights above the midplane. Azimuthal velocities are directly extracted from the PV diagrams using the envelope tracing method, and indicate an extremely steep dropoff in rotational velocity with increasing height, with magnitude ~30 km/s/kpc. We find evidence for a radial variation in the velocity gradient on the receding side. We have also performed artificial observations of galaxy models in an attempt to match the PV diagrams. The results of a statistical analysis also favor a gradient of ~30 km/s/kpc. We compare these results with an entirely ballistic model of disk-halo flow, and find a strong dichotomy between the observed kinematics and those predicted by the model. The disagreement is worse than we have found for other galaxies in previous studies. The conclusions of this paper are compared to results from two other galaxies, NGC 5775 and NGC 891. We find that the vertical gradient in rotation speed, per unit EDIG scale height, for all three galaxies is consistent with a constant magnitude (within the errors) of approximately 15-25 km/s/scaleheight, independent of radius. This relationship is also true within the galaxy NGC 4302. We also discuss how the gradient depends on the distribution and morphology of the EDIG and the star formation rates of the galaxies, and consequences for the origin of the gas.

  18. EXTENDED HOT HALOS AROUND ISOLATED GALAXIES OBSERVED IN THE ROSAT ALL-SKY SURVEY

    SciTech Connect (OSTI)

    Anderson, Michael E.; Bregman, Joel N. [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States)] [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Dai, Xinyu, E-mail: michevan@umich.edu, E-mail: jbregman@umich.edu, E-mail: xdai@ou.edu [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019 (United States)] [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019 (United States)

    2013-01-10

    We place general constraints on the luminosity and mass of hot X-ray-emitting gas residing in extended 'hot halos' around nearby massive galaxies. We examine stacked images of 2165 galaxies from the 2MASS Isolated Galaxy Catalog as well as subsets of this sample based on galaxy morphology and K-band luminosity. We detect X-ray emission at high confidence (ranging up to nearly 10{sigma}) for each subsample of galaxies. The average L{sub X} within 50 kpc is 1.0 {+-} 0.1 (statistical) {+-}0.2 (systematic) Multiplication-Sign 10{sup 40} erg s{sup -1}, although the early-type galaxies are more than twice as luminous as the late-type galaxies. Using a spatial analysis, we also find evidence for extended emission around five out of seven subsamples (the full sample, the luminous galaxies, early-type galaxies, luminous late-type galaxies, and luminous early-type galaxies) at 92.7%, 99.3%, 89.3%, 98.7%, and 92.1% confidence, respectively. Several additional lines of evidence also support this conclusion and suggest that about 1/2 of the total emission is extended, and about 1/3 of the extended emission comes from hot gas. For the sample of luminous galaxies, which has the strongest evidence for extended emission, the average hot gas mass is 4 Multiplication-Sign 10{sup 9} M {sub Sun} within 50 kpc and the implied accretion rate is 0.4 M {sub Sun} yr{sup -1}.

  19. OXYGEN ABUNDANCES IN NEARBY FGK STARS AND THE GALACTIC CHEMICAL EVOLUTION OF THE LOCAL DISK AND HALO

    SciTech Connect (OSTI)

    Ramirez, I.; Lambert, D. L. [McDonald Observatory and Department of Astronomy, University of Texas at Austin, 2515 Speedway, Stop C1400, Austin, TX 78712-1205 (United States)] [McDonald Observatory and Department of Astronomy, University of Texas at Austin, 2515 Speedway, Stop C1400, Austin, TX 78712-1205 (United States); Allende Prieto, C. [Instituto de Astrofisica de Canarias, E-38205 La Laguna, Tenerife (Spain)] [Instituto de Astrofisica de Canarias, E-38205 La Laguna, Tenerife (Spain)

    2013-02-10

    Atmospheric parameters and oxygen abundances of 825 nearby FGK stars are derived using high-quality spectra and a non-local thermodynamic equilibrium analysis of the 777 nm O I triplet lines. We assign a kinematic probability for the stars to be thin-disk (P {sub 1}), thick-disk (P {sub 2}), and halo (P {sub 3}) members. We confirm previous findings of enhanced [O/Fe] in thick-disk (P {sub 2} > 0.5) relative to thin-disk (P {sub 1} > 0.5) stars with [Fe/H] {approx}< -0.2, as well as a 'knee' that connects the mean [O/Fe]-[Fe/H] trend of thick-disk stars with that of thin-disk members at [Fe/H] {approx}> -0.2. Nevertheless, we find that the kinematic membership criterion fails at separating perfectly the stars in the [O/Fe]-[Fe/H] plane, even when a very restrictive kinematic separation is employed. Stars with 'intermediate' kinematics (P {sub 1} < 0.7, P {sub 2} < 0.7) do not all populate the region of the [O/Fe]-[Fe/H] plane intermediate between the mean thin-disk and thick-disk trends, but their distribution is not necessarily bimodal. Halo stars (P {sub 3} > 0.5) show a large star-to-star scatter in [O/Fe]-[Fe/H], but most of it is due to stars with Galactocentric rotational velocity V < -200 km s{sup -1}; halo stars with V > -200 km s{sup -1} follow an [O/Fe]-[Fe/H] relation with almost no star-to-star scatter. Early mergers with satellite galaxies explain most of our observations, but the significant fraction of disk stars with 'ambiguous' kinematics and abundances suggests that scattering by molecular clouds and radial migration have both played an important role in determining the kinematic and chemical properties of solar neighborhood stars.

  20. Fusion reaction of halo nuclei: A real-time wave-packet method for three-body tunneling dynamics

    E-Print Network [OSTI]

    T. Nakatsukasa; M. Ito; K. Yabana; M. Ueda

    2006-05-12

    We investigate fusion cross section of a nucleus with a valence neutron, using the time-dependent wave-packet method. For a stable projectile, in which the valence neutron is tightly bound (e_n fusion probability when the matching condition of orbital energies are satisfied. In contrast, for a halo nucleus, in which the binding energy of the neutron is very small (e_n>-1 MeV), the fusion probability is hindered by the presence of the weakly bound neutron.

  1. Mon. Not. R. Astron. Soc. 410, 210226 (2011) doi:10.1111/j.1365-2966.2010.17436.x Satellite kinematics III. Halo masses of central galaxies in SDSS

    E-Print Network [OSTI]

    Skibba, Ramin A.

    2011-01-01

    matter. The fluctuations in the dark matter density field grow under the action of gravity and form a web that orbit around the central galaxy in a dark matter halo to infer the scaling relations between halo mass of 2), indicating that we are converging on an accurate and reliable description of the galaxy­dark

  2. Baryon Cycling in the Low-Redshift Circumgalactic Medium: A Comparison of Simulations to the COS-Halos Survey

    E-Print Network [OSTI]

    Ford, Amanda Brady; Dave, Romeel; Tumlinson, Jason; Bordoloi, Rongmon; Katz, Neal; Kollmeier, Juna A; Oppenheimer, Benjamin D; Peeples, Molly S; Prochaska, Jason X; Weinberg, David H

    2015-01-01

    We analyze the low-redshift (z~0.2) circumgalactic medium by comparing absorption-line data from the COS-Halos Survey to absorption around a matched galaxy sample from two cosmological hydrodynamic simulations. The models include different prescriptions for galactic outflows, namely hybrid energy/momentum driven wind (ezw), and constant winds (cw). We extract for comparison direct observables including equivalent widths, covering factors, ion ratios, and kinematics. Both wind models are generally in good agreement with these observations for HI and certain low ionization metal lines, but show poorer agreement with higher ionization metal lines including SiIII and OVI that are well-observed by COS-Halos. These discrepancies suggest that both wind models predict too much cool, metal-enriched gas and not enough hot gas, and/or that the metals are not sufficiently well-mixed. This may reflect our model assumption of ejecting outflows as cool and unmixing gas. Our ezw simulation includes a heuristic prescription t...

  3. A hadronic-leptonic model for the Fermi bubbles: Cosmic-rays in the galactic halo and radio emission

    SciTech Connect (OSTI)

    Fujita, Yutaka; Ohira, Yutaka; Yamazaki, Ryo

    2014-07-01

    We investigate non-thermal emission from the Fermi bubbles in a hadronic model. Cosmic-ray (CR) protons are accelerated at the forward shock of the bubbles. They interact with the background gas in the Galactic halo and create ?{sup 0}-decay gamma-rays and secondary electrons through proton-proton interaction. We follow the evolution of the CR protons and electrons by calculating their distribution functions. We find that the spectrum and the intensity profiles of ?{sup 0}-decay gamma-rays are consistent with observations. We predict that the shock front is located far ahead of the gamma-ray boundary of the Fermi bubbles. This naturally explains the fact that a clear temperature jump of thermal gas was not discovered at the gamma-ray boundary in recent Suzaku observations. We also consider re-acceleration of the background CRs in the Galactic halo at the shock front. We find that it can significantly affect the gamma-rays from the Fermi bubbles, unless the density of the background CRs is ? 10% of that in the Galactic disk. We indicate that secondary electrons alone cannot produce the observed radio emission from the Fermi bubbles. However, the radio emission from the outermost region of the bubbles can be explained if electrons are directly accelerated at the shock front with an efficiency of ?0.1% of that of protons.

  4. Accurate calculations of the WIMP halo around the Sun and prospects for its gamma-ray detection

    SciTech Connect (OSTI)

    Sivertsson, Sofia; Edsjoe, Joakim

    2010-03-15

    Galactic weakly interacting massive particles (WIMPs) may scatter off solar nuclei to orbits gravitationally bound to the Sun. Once bound, the WIMPs continue to lose energy by repeated scatters in the Sun, eventually leading to complete entrapment in the solar interior. While the density of the bound population is highest at the center of the Sun, the only observable signature of WIMP annihilations inside the Sun is neutrinos. It has been previously suggested that although the density of WIMPs just outside the Sun is lower than deep inside, gamma rays from WIMP annihilation just outside the surface of the Sun, in the so-called WIMP halo around the Sun, may be more easily detected. We here revisit this problem using detailed Monte Carlo simulations and detailed composition and structure information about the Sun to estimate the size of the gamma-ray flux. Compared to earlier simpler estimates, we find that the gamma-ray flux from WIMP annihilations in the solar WIMP halo would be negligible; no current or planned detectors would be able to detect this flux.

  5. THE COS-HALOS SURVEY: AN EMPIRICAL DESCRIPTION OF METAL-LINE ABSORPTION IN THE LOW-REDSHIFT CIRCUMGALACTIC MEDIUM

    SciTech Connect (OSTI)

    Werk, Jessica K.; Prochaska, J. Xavier [UCO/Lick Observatory, University of California, Santa Cruz, CA (United States); Thom, Christopher; Tumlinson, Jason [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD (United States); Tripp, Todd M. [Department of Astronomy, University of Massachusetts, Amherst, MA (United States); O'Meara, John M. [Department of Chemistry and Physics, Saint Michael's College, Colchester, VT (United States); Peeples, Molly S., E-mail: jwerk@ucolick.org [Department of Physics and Astronomy, University of California, Los Angles, CA (United States)

    2013-02-15

    We present the equivalent width and column density measurements for low and intermediate ionization states of the circumgalactic medium (CGM) surrounding 44 low-z, L Almost-Equal-To L* galaxies drawn from the COS-Halos survey. These measurements are derived from far-UV transitions observed in HST/COS and Keck/HIRES spectra of background quasars within an impact parameter R < 160 kpc to the targeted galaxies. The data show significant metal-line absorption for 33 of the 44 galaxies, including quiescent systems, revealing the common occurrence of a cool (T Almost-Equal-To 10{sup 4}-10{sup 5} K), metal-enriched CGM. The detection rates and column densities derived for these metal lines decrease with increasing impact parameter, a trend we interpret as a declining metal surface density profile for the CGM. A comparison of the relative column densities of adjacent ionization states indicates that the gas is predominantly ionized. The large surface density in metals demands a large reservoir of metals and gas in the cool CGM (very conservatively, M {sup cool} {sub CGM} > 10{sup 9} M {sub Sun }), which likely traces a distinct density and/or temperature regime from the highly ionized CGM traced by O{sup +5} absorption. The large dispersion in absorption strengths (including non-detections) suggests that the cool CGM traces a wide range of densities or a mix of local ionizing conditions. Lastly, the kinematics inferred from the metal-line profiles are consistent with the cool CGM being bound to the dark matter halos hosting the galaxies; this gas may serve as fuel for future star formation. Future work will leverage this data set to provide estimates on the mass, metallicity, dynamics, and origin of the cool CGM in low-z, L* galaxies.

  6. The Century Survey Galactic Halo Project II: Global Properties and the Luminosity Function of Field Blue Horizontal Branch Stars

    E-Print Network [OSTI]

    Warren R. Brown; Margaret J. Geller; Scott J. Kenyon; Michael J. Kurtz; Carlos Allende Prieto; Timothy C. Beers; Ronald Wilhelm

    2005-05-16

    We discuss a 175 deg^2 spectroscopic survey for blue horizontal branch (BHB) stars in the Galactic halo. We use the Two Micron All Sky Survey (2MASS) and the Sloan Digital Sky Survey (SDSS) to select BHB candidates, and find that the 2MASS and SDSS color-selection is 38% and 50% efficient, respectively, for BHB stars. Our samples include one likely run-away B7 star 6 kpc below the Galactic plane. The global properties of the BHB samples are consistent with membership in the halo population: the median metallicity is [Fe/H]=-1.7, the velocity dispersion is 108 km/s, and the mean Galactic rotation of the BHB stars 3<|z|<15 kpc is -4 +- 30 km/s. We discuss the theoretical basis of the Preston, Shectman & Beers M_V-color relation for BHB stars, and conclude that intrinsic shape of the BHB M_V-color relation results from the physics of stars on the horizontal branch. We calculate the luminosity function for the field BHB star samples using the Efstathiou, Ellis, & Peterson maximum-likelihood method which is unbiased by density variations. The field BHB luminosity function exhibits a steep rise at bright luminosities, a peak between 0.8 < M_V < 1.0, and a tail at faint luminosities. We compare the field BHB luminosity functions with the luminosity functions derived from sixteen different globular cluster BHBs. Kolmogorov-Smirnov tests suggest that field BHB stars and BHB stars in globular clusters share a common distribution of luminosities, with the exception of globular clusters with extended BHBs.

  7. A WIDE-FIELD PHOTOMETRIC SURVEY FOR EXTRATIDAL TAILS AROUND FIVE METAL-POOR GLOBULAR CLUSTERS IN THE GALACTIC HALO

    SciTech Connect (OSTI)

    Chun, Sang-Hyun; Lee, Young-Wook; Sohn, Young-Jong; Kim, Jae-Woo; Sohn, Sangmo T.; Park, Jang-Hyun; Han, Wonyong; Kim, Ho-Il; Lee, Myung Gyoon; Lee, Sang-Gak

    2010-02-15

    Wide-field deep g'r'i' images obtained with the Megacam of the Canada-France-Hawaii Telescope are used to investigate the spatial configuration of stars around five metal-poor globular clusters M15, M30, M53, NGC 5053, and NGC 5466, in a field-of-view {approx}3 deg. Applying a mask filtering algorithm to the color-magnitude diagrams of the observed stars, we sorted cluster's member star candidates that are used to examine the characteristics of the spatial stellar distribution surrounding the target clusters. The smoothed surface density maps and the overlaid isodensity contours indicate that all of the five metal-poor globular clusters exhibit strong evidence of extratidal overdensity features over their tidal radii, in the form of extended tidal tails around the clusters. The orientations of the observed extratidal features show signatures of tidal tails tracing the clusters' orbits, inferred from their proper motions, and effects of dynamical interactions with the Galaxy. Our findings include detections of a tidal bridge-like feature and an envelope structure around the pair of globular clusters M53 and NGC 5053. The observed radial surface density profiles of target clusters have a deviation from theoretical King models, for which the profiles show a break at 0.5-0.7r{sub t} , extending the overdensity features out to 1.5-2r{sub t} . Both radial surface density profiles for different angular sections and azimuthal number density profiles confirm the overdensity features of tidal tails around the five metal-poor globular clusters. Our results add further observational evidence that the observed metal-poor halo globular clusters originate from an accreted satellite system, indicative of the merging scenario of the formation of the Galactic halo.

  8. Non-linear Simulations of MHD Instabilities in Tokamaks Including Eddy Current Effects and Perspectives for the Extension to Halo Currents

    E-Print Network [OSTI]

    Hoelzl, M; Merkel, P; Atanasiu, C; Lackner, K; Nardon, E; Aleynikova, K; Liu, F; Strumberger, E; McAdams, R; Chapman, I; Fil, A

    2014-01-01

    The dynamics of large scale plasma instabilities can strongly be influenced by the mutual interaction with currents flowing in conducting vessel structures. Especially eddy currents caused by time-varying magnetic perturbations and halo currents flowing directly from the plasma into the walls are important. The relevance of a resistive wall model is directly evident for Resistive Wall Modes (RWMs) or Vertical Displacement Events (VDEs). However, also the linear and non-linear properties of most other large-scale instabilities may be influenced significantly by the interaction with currents in conducting structures near the plasma. The understanding of halo currents arising during disruptions and VDEs, which are a serious concern for ITER as they may lead to strong asymmetric forces on vessel structures, could also benefit strongly from these non-linear modeling capabilities. Modeling the plasma dynamics and its interaction with wall currents requires solving the magneto-hydrodynamic (MHD) equations in realist...

  9. Dark-ages Reionization & Galaxy Formation Simulation II: Spin and concentration parameters for dark matter haloes during the Epoch of Reionization

    E-Print Network [OSTI]

    Angel, Paul W; Ludlow, Aaron D; Duffy, Alan R; Geil, Paul M; Mutch, Simon J; Mesinger, Andrei; Wyithe, J Stuart B

    2015-01-01

    We use high resolution N-Body simulations to study the concentration and spin parameters of dark matter haloes in the mass range $10^8\\, {\\rm M}_{\\odot}\\, h^{-1} }5$ concentration$-$mass ($c(M)$) relation that is almost flat and well described by a simple power-law for both NFW and Einasto fits. The intrinsic scatter around the mean relation is $\\Delta c_{\\rm{vir}}{\\sim1}$ (or 20 per cent) at $z=5$. We also find that the analytic model proposed by Ludlow et al. reproduces the mass and redshift-dependence of halo concentrations. Our best-fit Einasto shape parameter, $\\alpha$, depends on peak height, $\

  10. PROBING THE TRUNCATION OF GALAXY DARK MATTER HALOS IN HIGH-DENSITY ENVIRONMENTS FROM HYDRODYNAMICAL N-BODY SIMULATIONS

    SciTech Connect (OSTI)

    Limousin, Marceau; Sommer-Larsen, Jesper; Milvang-Jensen, Bo [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen (Denmark); Natarajan, Priyamvada [Astronomy Department, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States)], E-mail: marceau.limousin@oamp.fr

    2009-05-10

    We analyze high-resolution, N-body hydrodynamical simulations of fiducial galaxy clusters to probe tidal stripping of the dark matter subhalos. These simulations include a prescription for star formation allowing us to track the fate of the stellar component as well. We investigate the effect of tidal stripping on cluster galaxies hosted in these dark matter subhalos as a function of projected cluster-centric radius. To quantify the extent of the dark matter halos of cluster galaxies, we introduce the half-mass radius r {sub 1/2} as a diagnostic, and study its evolution with projected cluster-centric distance R as a function of redshift. We find a well-defined trend for (r {sub 1/2}, R): the closer the galaxies are to the center of the cluster, the smaller the half-mass radius. Interestingly, this trend is inferred in all redshift frames examined in this work ranging from z = 0 to z = 0.7. At z = 0, galaxy halos in the central regions of clusters are found to be highly truncated, with the most compact half-mass radius of 10 kpc. We also find that r {sub 1/2} depends on luminosity and we present scaling relations of r {sub 1/2} with galaxy luminosity. The corresponding total mass of the cluster galaxies is also found to increase with projected cluster-centric distance and luminosity, but with more scatter than the (r {sub 1/2}, R) trend. Comparing the distribution of stellar mass to total mass for cluster galaxies, we find that the dark matter component is preferentially stripped, whereas the stellar component is much less affected by tidal forces. We compare these results with galaxy-galaxy lensing probes of r {sub 1/2} and find qualitative agreement. Future surveys with space-based telescopes such as DUNE and SNAP, that combine wide-field and high-resolution imaging, will be able to probe the predicted (r {sub 1/2}, R) relation observationally.

  11. Neutron Halo Isomers in Stable Nuclei and their Possible Application for the Production of Low Energy, Pulsed, Polarized Neutron Beams of High Intensity and High Brilliance

    E-Print Network [OSTI]

    D. Habs; M. Gross; P. G. Thirolf; P. Böni

    2010-09-30

    We propose to search for neutron halo isomers populated via $\\gamma$-capture in stable nuclei with mass numbers of about A=140-180 or A=40-60, where the $4s_{1/2}$ or $3s_{1/2}$ neutron shell model state reaches zero binding energy. These halo nuclei can be produced for the first time with new $\\gamma$-beams of high intensity and small band width ($\\le$ 0.1%) achievable via Compton back-scattering off brilliant electron beams thus offering a promising perspective to selectively populate these isomers with small separation energies of 1 eV to a few keV. Similar to single-neutron halo states for very light, extremely neutron-rich, radioactive nuclei \\cite{hansen95,tanihata96,aumann00}, the low neutron separation energy and short-range nuclear force allows the neutron to tunnel far out into free space much beyond the nuclear core radius. This results in prolonged half lives of the isomers for the $\\gamma$-decay back to the ground state in the 100 ps-$\\mu$s range. Similar to the treatment of photodisintegration of the deuteron, the neutron release from the neutron halo isomer via a second, low-energy, intense photon beam has a known much larger cross section with a typical energy threshold behavior. In the second step, the neutrons can be released as a low-energy, pulsed, polarized neutron beam of high intensity and high brilliance, possibly being much superior to presently existing beams from reactors or spallation neutron sources.

  12. Constraining dark matter halo profiles and galaxy formation models using spiral arm morphology. II. Dark and stellar mass concentrations for 13 nearby face-on galaxies

    SciTech Connect (OSTI)

    Seigar, Marc S. [Department of Physics, University of Minnesota Duluth, 1023 University Drive, MWAH 371, Duluth, MN 55812-3009 (United States); Davis, Benjamin L.; Berrier, Joel; Kennefick, Daniel [Arkansas Center for Space and Planetary Sciences, 202 Field House, University of Arkansas, Fayetteville, AR 72701 (United States)

    2014-11-01

    We investigate the use of spiral arm pitch angles as a probe of disk galaxy mass profiles. We confirm our previous result that spiral arm pitch angles (P) are well correlated with the rate of shear (S) in disk galaxy rotation curves. We use this correlation to argue that imaging data alone can provide a powerful probe of galactic mass distributions out to large look-back times. We then use a sample of 13 galaxies, with Spitzer 3.6 ?m imaging data and observed H? rotation curves, to demonstrate how an inferred shear rate coupled with a bulge-disk decomposition model and a Tully-Fisher-derived velocity normalization can be used to place constraints on a galaxy's baryon fraction and dark matter halo profile. Finally, we show that there appears to be a trend (albeit a weak correlation) between spiral arm pitch angle and halo concentration. We discuss implications for the suggested link between supermassive black hole (SMBH) mass and dark halo concentration, using pitch angle as a proxy for SMBH mass.

  13. Chemical abundances in the extremely carbon-rich and xenon-rich halo planetary nebula H4-1

    SciTech Connect (OSTI)

    Otsuka, Masaaki [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China); Tajitsu, Akito, E-mail: otsuka@asiaa.sinica.edu.tw, E-mail: tajitsu@subaru.naoj.org [Subaru Telescope, NAOJ, 650 North A'ohoku Place, Hilo, HI 96720 (United States)

    2013-12-01

    We performed detailed chemical abundance analysis of the extremely metal-poor ([Ar/H] ? –2) halo planetary nebula (PN) H4-1 based on the multi-wavelength spectra from Subaru/HDS, GALEX, SDSS, and Spitzer/IRS and determined the abundances of 10 elements. The C and O abundances were derived from collisionally excited lines (CELs) and are almost consistent with abundances from recombination lines (RLs). We demonstrated that the large discrepancy in the C abundance between CEL and RL in H4-1 can be solved using the temperature fluctuation model. We reported the first detection of the [Xe III] ?5846 line in H4-1 and determination of its elemental abundance ([Xe/H] > +0.48). H4-1 is the most Xe-rich PN among the Xe-detected PNe. The observed abundances are close to the theoretical prediction by a 2.0 M {sub ?} single star model with an initially element rich ([r/Fe] = +2.0 dex) rapid neutron-capture process (r-process). The observed Xe abundance would be a product of the r-process in primordial supernovae. The [C/O]-[Ba/(Eu or Xe)] diagram suggests that the progenitor of H4-1 shares the evolution with carbon-enhanced metal-poor (CEMP)-r/s and CEMP-no stars. The progenitor of H4-1 is presumably a binary formed in an r-process-rich environment.

  14. Non-LTE analysis of copper abundances for the two distinct halo populations in the solar neighborhood

    E-Print Network [OSTI]

    Yan, H L; Nissen, P E; Zhao, G

    2015-01-01

    Two distinct halo populations were found in the solar neighborhood by a series of works. They can be clearly separated by [alpha\\Fe] and several other elemental abundance ratios including [Cu/Fe]. Very recently, a non-local thermodynamic equilibrium (non-LTE) study revealed that relatively large departures exist between LTE and non-LTE results in copper abundance analysis. We aim to derive the copper abundances for the stars from the sample of Nissen et al (2010) with both LTE and non-LTE calculations. Based on our results, we study the non-LTE effects of copper and investigate whether the high-alpha population can still be distinguished from the low-alpha population in the non-LTE [Cu/Fe] results. Our differential abundance ratios are derived from the high-resolution spectra collected from VLT/UVES and NOT/FIES spectrographs. Applying the MAFAGS opacity sampling atmospheric models and spectrum synthesis method, we derive the non-LTE copper abundances based on the new atomic model with current atomic data obt...

  15. Radio Emitting Dust in the Free-Electron Layer of Spiral Galaxies: Testing the Disk/Halo Interface

    E-Print Network [OSTI]

    A. Ferrara; R. J. Dettmar

    1994-01-10

    We present a study of the radio emission from rotating, charged dust grains immersed in the ionized gas constituting the thick, H$\\alpha$-emitting disk of many spiral galaxies. Using up-to-date optical constants, the charge on the grains exposed to the diffuse galactic UV flux has been calculated. An analytical approximation for the grain charge has been derived, which is then used to obtain the grain rotation frequency. Grains are found to have substantial radio emission peaked at a cutoff frequency in the range 10-100~GHz, depending on the grain size distribution and on the efficiency of the radiative damping of the grain rotation. The dust radio emission is compared to the free-free emission from the ionized gas component; some constraints on the magnetic field strength in the observed dusty filaments are also discussed. The model can be used to test the disk-halo interface environment in spiral galaxies, to determine the amount and size distribution of dust in their ionized component, and to investigate the rotation mechanisms for the dust. Numerical estimates are given for experimental purposes.

  16. Thorium-rich halo star HD221170: further evidence against the universality of the r-process

    E-Print Network [OSTI]

    Alexander Yushchenko; Vera Gopka; Stephane Goriely; Faig Musaev; Angelina Shavrina; Chulhee Kim; Young Woon Kang; Juliana Kuznietsova; Vladimir Yushchenko

    2004-09-22

    We report the abundance determination in the atmosphere of the bright halo star HD221170. The spectra were taken with the Terskol Observatory's 2.0-m telescope with a resolution R=45000 and signal-to-noise ratio up to 250 in the wavelength region 3638-10275 \\AA. The adopted atmospheric parameters correspond to an effective temperature \\Tef=4475 K, a surface gravity \\lgg=1.0, a microturbulent velocity \\vmi=1.7 \\kms, and a macroturbulent velocity \\vma=4 \\kms. The abundances of 43 chemical elements were determined with the method of spectrum synthesis. The large overabundances (by 1 dex relative to iron) of elements with Z$>38$ are shown to follow the same pattern as the solar r-abundances. The present HD221170 analysis confirms the non-universality of the r-process, or more exactly the observation that the astrophysical sites hosting the r-process do not always lead to a unique relative abundance distribution for the bulk Ba to Hg elements, the Pb-peak elements, and the actinides.

  17. Nuclear Charge Radii of Be-7,9,10 and the one-neutron halo nucleus Be-11

    E-Print Network [OSTI]

    W. Nörtershäuser; D. Tiedemann; M. Žáková; Z. Andjelkovic; K. Blaum; M. L. Bissell; R. Cazan; G. W. F. Drake; Ch. Geppert; M. Kowalska; J. Krämer; A. Krieger; R. Neugart; R. Sánchez; F. Schmidt-Kaler; Z. -C. Yan; D. T. Yordanov; C. Zimmermann

    2009-02-05

    Nuclear charge radii of $^{7,9,10,11}$Be have been determined by high-precision laser spectroscopy. On-line measurements were performed with collinear laser spectroscopy in the $2s_{1/2} \\to 2p_{1/2}$ transition on a beam of Be$^{+}$ ions. Collinear and anticollinear laser beams were used simultaneously and the absolute frequency determination using a frequency comb yielded an accuracy in the isotope-shift measurements of about 1 MHz. Combination with accurate calculations of the mass-dependent isotope shifts yield nuclear charge radii. The charge radius decreases from $^7$Be to $^{10}$Be and then increases for the halo nucleus $^{11}$Be. When comparing our results with predictions of {\\it ab initio} nuclear structure calculations we find good agreement. Additionally, the nuclear magnetic moment of $^7$Be was determined to be $-1.3995(5)\\mu_{\\rm N}$ and that of $^{11}$Be from a previous $\\beta$-NMR measurement was confirmed.

  18. L Prize Drives Technology Innovation, Energy Savings

    SciTech Connect (OSTI)

    2014-04-30

    Fact sheet that provides an overview of DOE's L Prize competition, which challenges industry to develop high-quality, high-efficiency SSL products to replace 60W incandescent and PAR38 halogen light bulbs, and highlights the competition's first 60W winner from Philips Lighting North America.

  19. AN OVER-AND-OUT HALO CORONAL MASS EJECTION DRIVEN BY THE FULL ERUPTION OF A KINKED FILAMENT

    SciTech Connect (OSTI)

    Yang Jiayan; Jiang Yunchun; Bi Yi; Li Haidong; Hong Junchao; Yang Dan; Zheng Ruisheng; Yang Bo

    2012-04-10

    Over-and-out coronal mass ejections (CMEs) represent a broad class of CMEs that come from flare-producing magnetic explosions of various sizes but are laterally far offset from the flare, and their productions can be depicted by the magnetic-arch-blowout scenario. In this paper, we present observations of an over-and-out halo CME from the full eruption of a small kinking filament in an emerging active region (AR). In combination with the results of a derived coronal magnetic configuration, our observations showed that the CME was associated with a coronal helmet streamer, and the filament was located in the northern outskirts of the streamer base. Formed along a neutral line where flux cancellation was forced by the emerging AR with the surrounding opposite-polarity magnetic field, the filament underwent a full, non-radial eruption along the northern leg of the streamer arcade, accompanied by a clockwise deflection of the eruption direction. As a characteristic property of kink instability, the eruption displayed a clear inverse {gamma} shape, indicative of a writhing motion of the filament apex. Coronal dimmings, including a remote one, formed in opposite-polarity footprint regions of the streamer arcade during the eruption, and the consequent CME was laterally offset from the AR. These observations suggest that the kink instability is likely to be the driver in the eruption. The event can be well explained by putting this driver into the magnetic-arch-blowout model, in which the eruption-direction deflection and the full-eruption nature of the kinking filament are caused by the guiding action of the streamer arcade and the external reconnection between them.

  20. Mapping the Dynamics of a Giant Ly-alpha Halo at z=4.1 with MUSE: The Energetics of a Large Scale AGN-Driven Outflow around a Massive, High-Redshift Galaxy

    E-Print Network [OSTI]

    Swinbank, Mark; Smail, Ian; De Breuck, Carlos; Bacon, Roland; Contini, Thierry; Richard, Johan; Rottgering, Huub; Urritia, Tanya; Venemans, Bram

    2015-01-01

    We present deep MUSE integral-field unit (IFU) spectroscopic observations of the giant (~150 x 80 kpc) Ly-alpha halo around the z=4.1 radio galaxy TNJ J1338-1942. This 9-hr observation maps the two-dimensional kinematics of the Ly-alpha emission across the halo. We identify two HI absorbers which are seen against the Ly-alpha emission, both of which cover the full 150 x 80 kpc extent of the halo and so have covering fractions ~1. The stronger and more blue-shifted absorber (dv~1200 km/s) has dynamics that mirror that of the underlying halo emission and we suggest that this high column material (n(HI) ~ 10^19.4 /cm^2), which is also seen in CIV absorption, represents an out-flowing shell that has been driven by the AGN (or star formation) within the galaxy. The weaker (n(HI)~10^14 /cm^2) and less blue shifted (dv~500 km/s) absorber most likely represents material in the cavity between the out-flowing shell and the Ly-alpha halo. We estimate that the mass in the shell must be of order 10^10 Msol -- a significan...

  1. THE INFLUENCE OF DARK MATTER HALOS ON DYNAMICAL ESTIMATES OF BLACK HOLE MASS: 10 NEW MEASUREMENTS FOR HIGH-{sigma} EARLY-TYPE GALAXIES

    SciTech Connect (OSTI)

    Rusli, S. P.; Thomas, J.; Saglia, R. P.; Fabricius, M.; Erwin, P.; Bender, R.; Nowak, N.; Lee, C. H.; Riffeser, A.; Sharp, R.

    2013-09-15

    Adaptive optics assisted SINFONI observations of the central regions of 10 early-type galaxies are presented. Based primarily on the SINFONI kinematics, 10 black hole (BH) masses occupying the high-mass regime of the M{sub BH}-{sigma} relation are derived using three-integral Schwarzschild models. The effect of dark matter (DM) inclusion on the BH mass is explored. The omission of a DM halo in the model results in a higher stellar mass-to-light ratio, especially when extensive kinematic data are used in the model. However, when the diameter of the sphere of influence-computed using the BH mass derived without a dark halo-is at least 10 times the point-spread function FWHM during the observations, it is safe to exclude a DM component in the dynamical modeling, i.e., the change in BH mass is negligible. When the spatial resolution is marginal, restricting the mass-to-light ratio to the right value returns the correct M{sub BH} although a dark halo is not present in the model. Compared to the M{sub BH}-{sigma} and M{sub BH}-L relations of McConnell et al., the 10 BHs are all more massive than expected from the luminosities and 7 BH masses are higher than expected from the stellar velocity dispersions of the host bulges. Using new fitted relations, which include the 10 galaxies, we find that the space density of the most massive BHs (M{sub BH} {approx}> 10{sup 9} M{sub Sun }) estimated from the M{sub BH}-L relation is higher than the estimate based on the M{sub BH}-{sigma} relation and the latter is higher than model predictions based on quasar counts, each by about an order of magnitude.

  2. Hydro-Gravitational-Dynamics Interpretation of the Tadpole VV29 Merging Galaxy System: Dark-Matter-Halo-Planet Star-Cluster Wakes

    E-Print Network [OSTI]

    Carl H. Gibson

    2008-03-29

    Hubble Space telescope (HST) images of merging galaxy system VV29 reveal the 0.3 Mpc baryonic-dark-matter (BDM) halo composed of primordial protoglobularstarcluster (PGC) clumps of planets. Star-cluster-wakes trace the merger by formation of stars from the planets. Aligned young globular star clusters (YGCs), star-wakes and dust-trails show the frictional, spiral passage of galaxy fragments VV29cdef in a long tail-like galaxy (VV29b) as the fragments merge on the accretion disk plane of the central spiral galaxy VV29a. The observations confirm the hydro-gravitational-dynamics (HGD) prediction of Gibson 1996 and quasar microlensing inference of Schild 1996 that the dark matter of galaxies is dominated by planets (PFPs) in million-solar-mass clumps. Globular star clusters (YGCs, OGCs, PGCs) preserve the density of the plasma epoch 30,000 years after the big bang when viscous supercluster-fragmentation began. Tadpole images show linear galaxy clusters reflecting turbulent vortex lines of protogalaxy fragmentation at the 0.003 Mpc Kolmogorov-Nomura scale of the plasma before transition to gas. The halo size indicates strong diffusion of PGC primordial-planet-clumps from a cooling protogalaxy as its planets freeze.

  3. RELICS OF GALAXY MERGING: OBSERVATIONAL PREDICTIONS FOR A WANDERING MASSIVE BLACK HOLE AND ACCOMPANYING STAR CLUSTER IN THE HALO OF M31

    SciTech Connect (OSTI)

    Kawaguchi, Toshihiro; Saito, Yuriko; Miki, Yohei; Mori, Masao

    2014-07-01

    Galaxies and massive black holes (BHs) presumably grow via galactic merging events and subsequent BH coalescence. As a case study, we investigate the merging event between the Andromeda galaxy (M31) and a satellite galaxy. We compute the expected observational appearance of the massive BH that was at the center of the satellite galaxy prior to the merger and is currently wandering in the M31 halo. We demonstrate that a radiatively inefficient accretion flow with a bolometric luminosity of a few tens of solar luminosities develops when Hoyle-Lyttleton accretion onto the BH is assumed. We compute the associated broadband spectrum and show that the radio band (observable with EVLA, ALMA, and the Square Kilometre Array) is the best frequency range in which to detect the emission. We also evaluate the mass and the luminosity of the stars bound by the wandering BH and find that such a star cluster is sufficiently luminous that it could correspond to one of the star clusters found by the PAndAS survey. The discovery of a relic massive BH wandering in a galactic halo will provide a direct means of investigating in detail the coevolution of galaxies and BHs. It also means a new population of BHs (off-center massive BHs) and offers targets for clean BH imaging that avoid strong interstellar scattering in the centers of galaxies.

  4. Tracing the propagation of cosmic rays in the Milky Way halo with Fermi-LAT observations of high- and intermediate-velocity clouds

    E-Print Network [OSTI]

    Tibaldo, L

    2015-01-01

    Cosmic rays up to at least PeV energies are usually described in the framework of an elementary scenario that involves acceleration by objects that are located in the disk of the Milky Way, such as supernova remnants or massive star-forming regions, and then diffusive propagation throughout the Galaxy. Details of the propagation process are so far inferred mainly from the composition of cosmic rays measured near the Earth and then extrapolated to the whole Galaxy. The details of the propagation in the Galactic halo and the escape into the intergalactic medium remain uncertain. The densities of cosmic rays in specific locations can be traced via the gamma rays they produce in inelastic collisions with clouds of interstellar gas. Therefore, we analyze 73 months of Fermi-LAT data from 300 MeV to 10 GeV in the direction of several high- and intermediate-velocity clouds that are located in the halo of the Milky Way. These clouds are supposed to be free of internal sources of cosmic rays and hence any gamma-ray emi...

  5. Globular clusters in the outer Galactic halo: new HST/ACS imaging of 6 globular clusters and the Galactic globular cluster age-metallicity relation

    E-Print Network [OSTI]

    Dotter, Aaron; Anderson, Jay

    2011-01-01

    Color-magnitude diagrams (CMDs) derived from Hubble Space Telescope (HST) Advanced Camera for Surveys F606W,F814W photometry of 6 globular clusters (GCs) are presented. The six GCs form two loose groupings in Galactocentric distance (Rgc): IC 4499, NGC 6426, and Ruprecht 106 at ~15-20 kpc and NGC 7006, Palomar 15, and Pyxis at ~40 kpc. The CMDs allow the ages to be estimated from the main sequence turnoff in every case. In addition, the age of Palomar 5 (Rgc ~ 18 kpc) is estimated using archival HST Wide Field Planetary Camera 2 V,I photometry. The age analysis reveals the following: IC 4499, Ruprecht 106, and Pyxis are 1-2 Gyr younger than inner halo GCs with similar metallicities; NGC 7006 and Palomar 5 are marginally younger than their inner halo counterparts; NGC 6426 and Palomar 15, the two most metal-poor GCs in the sample, are coeval with all the other metal-poor GCs within the uncertainties. Combined with our previous efforts, the current sample provides strong evidence that the Galactic GC age-metall...

  6. Tracing the tidal streams of the Sagittarius dSph, and halo Milky Way features, with carbon-rich long-period variables

    E-Print Network [OSTI]

    Huxor, Avon

    2015-01-01

    We assemble 121 spectroscopically-confirmed halo carbon stars, drawn from the literature, exhibiting measurable variability in the Catalina Surveys. We present their periods and amplitudes, which are used to estimate distances from period-luminosity relationships. The location of the carbon stars - and their velocities when available - allow us to trace the streams of the Sagittarius (Sgr) dwarf spheroidal galaxy. These are compared to a canonical numerical simulation of the accretion of Sgr. We find that the data match this model well for heliocentric distances of 15-50 kpc, except for a virtual lack of carbon stars in the trailing arm just north of the Galactic Plane, and there is only tentative evidence of the leading arm south of the Plane. The majority of the sample can be attributed to the Sgr accretion. We also find groups of carbon stars which are not part of Sgr; most of which are associated with known halo substructures. A few have no obvious attribution and may indicate new substructure. We find ev...

  7. We are using both space-based (Hubble Space Telescope, HST) and ground-based telescopes to make extensive studies of Galactic halo stars. These stars contain nucleosynthesis products (from the rapid neutron capture process, r-process) from the

    E-Print Network [OSTI]

    Cowan, John

    to make extensive studies of Galactic halo stars. These stars contain nucleosynthesis products (from Galactic r-process nucleosynthesis. These in turn will help to identify the characteristics and nature ­ particularly the sites and the astrophysical conditions for their formation EARLY GALACTIC NUCLEOSYNTHESIS

  8. Why Did the LED Light Bulb Cross the Road?

    Office of Energy Efficiency and Renewable Energy (EERE)

    Could using humor as a marketing strategy make energy efficiency a bit more digestible? One Illinois grant recipient thinks it could be.

  9. OKLAHOMA MESONET Wet Bulb Globe Temperature (WBGT) What is WBGT?

    E-Print Network [OSTI]

    Oklahoma, University of

    , wind speed, sun angle and cloud cover (solar radiation). Why use WBGT? WBGT uses a multitude of parameters that impact body temperature. Heat index only uses temperature and humidity regardless of wind

  10. OLFACTORY BULB MONOAMINE CONCENTRATIONS VARY WITH TIME OF DAY

    E-Print Network [OSTI]

    of operating indepen- dently of the master circadian pacemaker, the suprachiasmatic nuclei of the hypothalamus the suprachiasmatic nuclei of the hypothalamus (SCN), called the ``master circadian pacemaker.'' However structures may interact via OB connection to the lateral hypothalamus (Scott and Pfaffmann, 1967), the SCN

  11. Purchasing Energy-Efficient Light Bulbs | Department of Energy

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

    trap heat and increase temperatures in which lamps operate. This heat build-up can impact the performance and life expectancy of certain CFL or LED products. When purchasing...

  12. L Prize™: The Race for Super Efficient Light Bulbs

    Broader source: Energy.gov [DOE]

    This September 23, 2008 webcast provided an overview of the Bright Tomorrow Lighting Prize (L Prize) technology competition. The L Prize calls for super-efficient SSL products to replace two of the...

  13. Purchasing Energy-Efficient Light Bulbs | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious RankADVANCED MANUFACTURINGEnergy BillsNo. 195 - Oct. 7, 2011 |1 DOE Hydrogen and FuelAwardee: City

  14. Westinghouse and Fuzhou Permitted to Restart Distribution of Light Bulb

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousMathematics And Statistics » USAJobs SearchAMERICA'S FUTURE.Projects atWeRenewable Energy Zones-PhaseProducts

  15. The History of the Light Bulb | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustmentsShirley Ann JacksonDepartment ofOffice|inWestMayBuildingTheEasements &A TenOutages1 ofMarissaRead

  16. How Energy-Efficient Light Bulbs Compare with Traditional Incandescents |

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE: Alternative Fuelsof Energy ServicesContracting OversightEMSHome

  17. The History of the Light Bulb | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE: Alternative FuelsofProgram: Report15 MeetingDevelopmentDepartment ofTestimony5Nuclear Power

  18. HELSINKI UNIVERSITY OF TECHNOLOGY ENE-47.153 Halogens, dioxins/Halogens, dioxins/furansfurans

    E-Print Network [OSTI]

    Zevenhoven, Ron

    -500 / 50-2000/0.5 -90 Light fuel oil - Peat ~ 500 Heavy fuel oil - / oil shale ~2000 & electronic equip- ment (E&E) waste plastics * ~ 3.5 / ~ 0.9 Sewage sludge 0.03 - 1 Mixed medical waste 1 - 4

  19. Hydro-Gravitational-Dynamics Interpretation of the Tadpole VV29 Merging Galaxy System: Dark-Matter-Halo-Planet Star-Cluster Wakes

    E-Print Network [OSTI]

    Gibson, Carl H

    2008-01-01

    Hubble Space telescope (HST) images of merging galaxy system VV29 reveal the 0.3 Mpc baryonic-dark-matter (BDM) halo composed of primordial protoglobularstarcluster (PGC) clumps of planets. Star-cluster-wakes trace the merger by formation of stars from the planets. Aligned young globular star clusters (YGCs), star-wakes and dust-trails show the frictional, spiral passage of galaxy fragments VV29cdef in a long tail-like galaxy (VV29b) as the fragments merge on the accretion disk plane of the central spiral galaxy VV29a. The observations confirm the hydro-gravitational-dynamics (HGD) prediction of Gibson 1996 and quasar microlensing inference of Schild 1996 that the dark matter of galaxies is dominated by planets (PFPs) in million-solar-mass clumps. Globular star clusters (YGCs, OGCs, PGCs) preserve the density of the plasma epoch 30,000 years after the big bang when viscous supercluster-fragmentation began. Tadpole images show linear galaxy clusters reflecting turbulent vortex lines of protogalaxy fragmentatio...

  20. The Influence of a Kinematically Cold Young Component on Disc-Halo Decompositions in Spiral Galaxies: Insights from Solar Neighbourhood K-giants

    E-Print Network [OSTI]

    Aniyan, S; Gerhard, O E; Arnaboldi, M; Flynn, C

    2015-01-01

    In decomposing the HI rotation curves of disc galaxies, it is necessary to break a degeneracy between the gravitational fields of the disc and the dark halo by estimating the disc surface density. This is done by combining measurements of the vertical velocity dispersion of the disc with the disc scale height. The vertical velocity dispersion of the discs is measured from absorption lines (near the V-band) of near-face-on spiral galaxies, with the light coming from a mixed population of giants of all ages. However, the scale heights for these galaxies are estimated statistically from near-IR surface photometry of edge-on galaxies. The scale height estimate is therefore dominated by a population of older (> 2 Gyr) red giants. In this paper, we demonstrate the importance of measuring the velocity dispersion for the same older population of stars that is used to estimate the vertical scale height. We present an analysis of the vertical kinematics of K-giants in the solar vicinity. We find the vertical velocity d...

  1. Hot Gas Halos in Galaxies

    SciTech Connect (OSTI)

    Mulchaey, John S. [Carnegie Observatories (United States); Jeltema, Tesla E. [UCO/Lick Observatories (United States)

    2010-06-08

    We use Chandra and XMM-Newton to study how the hot gas content in early-type galaxies varies with environment. We find that the L{sub X}-L{sub K} relationship is steeper for field galaxies than for comparable galaxies in groups and clusters. This suggests that internal processes such as supernovae driven winds or AGN feedback may expel hot gas from low mass field galaxies. Such mechanisms are less effective in groups and clusters where the presence of an intragroup or intracluster medium may confine outflowing material.

  2. Theoretical studies of the dynamics of chemical reactions

    SciTech Connect (OSTI)

    Wagner, A.F. [Argonne National Laboratory, IL (United States)

    1993-12-01

    Recent research effort has focussed on several reactions pertinent to combustion. The formation of the formyl radical from atomic hydrogen and carbon monoxide, recombination of alkyl radicals and halo-alkyl radicals with halogen atoms, and the thermal dissociation of hydrogen cyanide and acetylene have been studied by modeling. In addition, the inelastic collisions of NCO with helium have been investigated.

  3. Accumulation and Metabolism of Halogenated Compounds in Sea Turtles

    E-Print Network [OSTI]

    Richardson, Kristine Lynn

    2010-01-01

    Toxicological and Environmental Chemistry 34(1): 19- Lakesparverius). Environmental Toxicology and Chemistry 20(11):hepatocytes. Environmental Toxicology and Chemistry 25(2):

  4. Inert gas rejection device for zinc-halogen battery systems

    DOE Patents [OSTI]

    Hammond, Michael J. (Sterling Heights, MI); Arendell, Mark W. (Warren, MI)

    1981-01-01

    An electrolytic cell for separating chlorine gas from other (foreign) gases, having an anode, a cathode assembly, an aqueous electrolyte, a housing, and a constant voltage power supply. The cathode assembly is generally comprised of a dense graphite electrode having a winding channel formed in the face opposing the anode, a gas impermeable (but liquid permeable) membrane sealed into the side of the cathode electrode over the channel, and a packing of graphite particles contained in the channel of the cathode electrode. The housing separates and parallelly aligns the anode and cathode assembly, and provides a hermetic seal for the cell. In operation, a stream of chlorine and foreign gases enters the cell at the beginning of the cathode electrode channel. The chlorine gas is dissolved into the electrolyte and electrochemically reduced into chloride ions. The chloride ions disfuse through the gas impermeable membrane, and are electrochemically oxidized at the anode into purified chlorine gas. The foreign gases do not participate in the above electrochemical reactions, and are vented from the cell at the end of the cathode electrode channel.

  5. Nature's Inventory of Halogenation Catalysts: Oxidative Strategies Predominate

    E-Print Network [OSTI]

    biosynthetic gene clusters, enabling coordinate regulation to activate these secondary metabolite pathways the abundance of chloride and bromide ions in microenvironments of terrestrial and marine producer organisms

  6. Synthesis and Characterization of Halogen-Free Antiflammable Polyphosphonates Containing

    E-Print Network [OSTI]

    flammability. Polyethylene and polypropylene, for example, possess heat of combustion properties on par a diffusion barrier of gaseous products to the flame, shields the polymer surface from heat and oxygen

  7. Accumulation and Metabolism of Halogenated Compounds in Sea Turtles

    E-Print Network [OSTI]

    Richardson, Kristine Lynn

    2010-01-01

    rat liver cytosol with styrene oxide and 35 S-GSH, and B)PB-treated rat cytosol with styrene oxide and 35 S-GSH (seeglutathione conjugate of styrene as a standard. However, GS-

  8. Manganese Porphyrins Catalyze Selective C-H Bond Halogenations

    SciTech Connect (OSTI)

    Liu, Wei; Groves, John T

    2010-01-01

    We report a manganese porphyrin mediated aliphatic C?H bond chlorination using sodium hypochlorite as the chlorine source. In the presence of catalytic amounts of phase transfer catalyst and manganese porphyrin Mn(TPP)Cl 1, reaction of sodium hypochlorite with different unactivated alkanes afforded alkyl chlorides as the major products with only trace amounts of oxygenation products. Substrates with strong C?H bonds, such as neopentane (BDE =?100 kcal/mol) can be also chlorinated with moderate yield. Chlorination of a diagnostic substrate, norcarane, afforded rearranged products indicating a long-lived carbon radical intermediate. Moreover, regioselective chlorination was achieved by using a hindered catalyst, Mn(TMP)Cl, 2. Chlorination of trans-decalin with 2 provided 95% selectivity for methylene-chlorinated products as well as a preference for the C2 position. This novel chlorination system was also applied to complex substrates. With 5?-cholestane as the substrate, we observed chlorination only at the C2 and C3 positions in a net 55% yield, corresponding to the least sterically hindered methylene positions in the A-ring. Similarly, chlorination of sclareolide afforded the equatorial C2 chloride in a 42% isolated yield. Regarding the mechanism, reaction of sodium hypochlorite with the Mn{sup III} porphyrin is expected to afford a reactive Mn{sup V}?O complex that abstracts a hydrogen atom from the substrate, resulting in a free alkyl radical and a Mn{sup IV}—OH complex. We suggest that this carbon radical then reacts with a Mn{sup IV}—OCl species, providing the alkyl chloride and regenerating the reactive Mn{sup V}?O complex. The regioselectivity and the preference for CH{sub 2} groups can be attributed to nonbonded interactions between the alkyl groups on the substrates and the aryl groups of the manganese porphyrin. The results are indicative of a bent [Mn{sup v}?O---H---C] geometry due to the C—H approach to the Mn{sup v}?O (d??p?)* frontier orbital.

  9. Accumulation and Metabolism of Halogenated Compounds in Sea Turtles

    E-Print Network [OSTI]

    Richardson, Kristine Lynn

    2010-01-01

    tetrachlorodibenzo-p-dioxin (TCDD) (Poland et al. 1976;from PCBs seem to stem from dioxin- like congeners, but thetetrachlorodibenzo-p-dioxin- induced toxicity. Toxicology

  10. Halogenated sulfidohydroboranes for nuclear medicine and boron neutron capture therapy

    DOE Patents [OSTI]

    Miura, Michiko (Hampton Bays, NY); Slatkin, Daniel N. (Southold, NY)

    1995-10-03

    A method for performing boron neutron capture therapy for the treatment of tumors is disclosed. The method includes administering to a patient an iodinated sulfidohydroborane, a boron-10-containing compound. The site of the tumor is localized by visualizing the increased concentration of the iodine labelled compound at the tumor. The targeted tumor is then irradiated with a beam of neutrons having an energy distribution effective for neutron capture. Destruction of the tumor occurs due to high LET particle irradiation of the tissue secondary to the incident neutrons being captured by the boron-10 nuclei. Iodinated sulfidohydroboranes are disclosed which are especially suitable for the method of the invention. In a preferred embodiment, a compound having the formula Na.sub.4 B.sub.12 I.sub.11 SSB.sub.12 I.sub.11, or another pharmaceutically acceptable salt of the compound, may be administered to a cancer patient for boron neutron capture therapy.

  11. Halogenated sulfidohydroboranes for nuclear medicine and boron neutron capture therapy

    DOE Patents [OSTI]

    Miura, M.; Slatkin, D.N.

    1995-10-03

    A method for performing boron neutron capture therapy for the treatment of tumors is disclosed. The method includes administering to a patient an iodinated sulfidohydroborane, a boron-10-containing compound. The site of the tumor is localized by visualizing the increased concentration of the iodine labelled compound at the tumor. The targeted tumor is then irradiated with a beam of neutrons having an energy distribution effective for neutron capture. Destruction of the tumor occurs due to high LET particle irradiation of the tissue secondary to the incident neutrons being captured by the boron-10 nuclei. Iodinated sulfidohydroboranes are disclosed which are especially suitable for the method of the invention. In a preferred embodiment, a compound having the formula Na{sub 4}B{sub 12}I{sub 11}SSB{sub 12}I{sub 11}, or another pharmaceutically acceptable salt of the compound, may be administered to a cancer patient for boron neutron capture therapy. 1 fig.

  12. Halogenated sulfidohydroboranes for nuclear medicine and boron neutron capture therapy

    DOE Patents [OSTI]

    Miura, M.; Slatkin, D.N.

    1997-08-05

    A method for performing boron neutron capture therapy for the treatment of tumors is disclosed. The method includes administering to a patient an iodinated sulfidohydroborane, a boron-10-containing compound. The site of the tumor is localized by visualizing the increased concentration of the iodine labelled compound at the tumor. The targeted tumor is then irradiated with a beam of neutrons having an energy distribution effective for neutron capture. Destruction of the tumor occurs due to high LET particle irradiation of the tissue secondary to the incident neutrons being captured by the boron-10 nuclei. Iodinated sulfidohydroboranes are disclosed which are especially suitable for the method of the invention. In a preferred embodiment, a compound having the formula Na{sub 4}B{sub 12}I{sub 11}SSB{sub 12}I{sub 11}, or another pharmaceutically acceptable salt of the compound, may be administered to a cancer patient for boron neutron capture therapy. 1 fig.

  13. Halogenated sulfidohydroboranes for nuclear medicine and boron neutron capture therapy

    DOE Patents [OSTI]

    Miura, Michiko (Hampton Bays, NY); Slatkin, Daniel N. (Southold, NY)

    1997-08-05

    A method for performing boron neutron capture therapy for the treatment of tumors is disclosed. The method includes administering to a patient an iodinated sulfidohydroborane, a boron-10-containing compound. The site of the tumor is localized. by visualizing the increased concentration of the iodine labelled compound at the tumor. The targeted tumor is then irradiated with a beam of neutrons having an energy distribution effective for neutron capture. Destruction of the tumor occurs due to high LET particle irradiation of the tissue secondary to the incident neutrons being captured by the boron-10 nuclei. Iodinated sulfidohydroboranes are disclosed which are especially suitable for the method of the invention. In a preferred embodiment, a compound having the formula Na.sub.4 B.sub.12 I.sub.11 SSB.sub.12 I.sub.11, or another pharmaceutically acceptable salt of the compound, may be administered to a cancer patient for boron neutron capture therapy.

  14. Halogenated sulfidohydroboranes for nuclear medicine and boron neutron capture therapy

    DOE Patents [OSTI]

    Miura, M.; Slatkin, D.N.

    1997-03-18

    A method for performing boron neutron capture therapy for the treatment of tumors is disclosed. The method includes administering to a patient an iodinated sulfidohydroborane, a boron-10-containing compound. The site of the tumor is localized by visualizing the increased concentration of the iodine labelled compound at the tumor. The targeted tumor is then irradiated with a beam of neutrons having an energy distribution effective for neutron capture. Destruction of the tumor occurs due to high LET particle irradiation of the tissue secondary to the incident neutrons being captured by the boron-10 nuclei. Iodinated sulfidohydroboranes are disclosed which are especially suitable for the method of the invention. In a preferred embodiment, a compound having the formula Na{sub 4}B{sub 12}I{sub 11}SSB{sub 12}I{sub 11}, or another pharmaceutically acceptable salt of the compound, may be administered to a cancer patient for boron neutron capture therapy. 1 fig.

  15. Halogenated sulfidohydroboranes for nuclear medicine and boron neutron capture therapy

    DOE Patents [OSTI]

    Miura, Michiko (Hampton Bays, NY); Slatkin, Daniel N. (Southold, NY)

    1997-03-18

    A method for performing boron neutron capture therapy for the treatment of tumors is disclosed. The method includes administering to a patient an iodinated sulfidohydroborane, a boron-10-containing compound. The site of the tumor is localized by visualizing the increased concentration of the iodine labelled compound at the tumor. The targeted tumor is then irradiated with a beam of neutrons having an energy distribution effective for neutron capture. Destruction of the tumor occurs due to high LET particle irradiation of the tissue secondary to the incident neutrons being captured by the boron-10 nuclei. Iodinated sulfidohydroboranes are disclosed which are especially suitable for the method of the invention. In a preferred embodiment, a compound having the formula Na.sub.4 B.sub.12 I.sub.11 SSB.sub.12 I.sub.11, or another pharmaceutically acceptable salt of the compound, may be administered to a cancer patient for boron neutron capture therapy.

  16. Determining thermochemical properties of halogenated metals: On enabling

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing BacteriaConnectlaser-solid interactionCrystalDesigning(JournalProblemsofofthe rapid

  17. Determining thermochemical properties of halogenated metals: On enabling

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing BacteriaConnectlaser-solid interactionCrystalDesigning(JournalProblemsofofthe

  18. Halo and Galaxy Formation Histories from the Millennium Simulation: Public release of a VO-oriented and SQL-queryable database for studying the evolution of galaxies in the LambdaCDM cosmogony

    E-Print Network [OSTI]

    G. Lemson; the Virgo Consortium

    2006-08-03

    The Millennium Run is the largest simulation of the formation of structure within the $\\Lambda$CDM cosmogony so far carried out. It uses $10^{10}$ particles to follow the dark matter distribution in a cubic region 500$h^{-1}$Mpc on a side, and has a spatial resolution of 5 $h^{-1}$kpc. Application of simplified modelling techniques to the stored output of this calculation allows the formation and evolution of the $\\sim 10^7$ galaxies more luminous than the Small Magellanic Cloud to be simulated for a variety of assumptions about the detailed physics involved. As part of the activities of the German Astrophysical Virtual Observatory we have used a relational database to store the detailed assembly histories both of all the haloes and subhaloes resolved by the simulation, and of all the galaxies that form within these structures for two independent models of the galaxy formation physics. We have created web applications that allow users to query these databases remotely using the standard Structured Query Language (SQL). This allows easy access to all properties of the galaxies and halos, as well as to the spatial and temporal relations between them and their environment. Information is output in table format compatible with standard Virtual Observatory tools and protocols. With this announcement we are making these structures fully accessible to all users. Interested scientists can learn SQL, gain familiarity with the database design and test queries on a small, openly accessible version of the Millennium Run (with volume 1/512 that of the full simulation). They can then request accounts to run similar queries on the databases for the full simulations.

  19. Second Exam Probability

    E-Print Network [OSTI]

    Glowinski, Roland

    supply room contains four 40-W lightbulbs, five 60-W bulbs, and six 75-W bulbs. Suppose that three bulbs

  20. Frequently Asked Questions Information on Compact Fluorescent Light Bulbs (CFLs) and Mercury

    E-Print Network [OSTI]

    Jia, Songtao

    home's electric bill. ENERGY STAR qualified CFLs use up to 75 percent less energy than incandescent, in one year it would save enough energy to light more than 3 million homes and prevent greenhouse gas, accessible change every American can make right now to reduce energy use at home and prevent greenhouse gas

  1. M362K First Midterm Exam Solutions. February 7, 2002 Problem 1. Light Bulbs

    E-Print Network [OSTI]

    Voloch, Felipe

    that the nickel was heads and the dime and quarter were tails. S = {HHH, HHT, HTH, HTT, THH, THT, TTH, TTT}. (Each of these 8 points has probability 1/8). 2 #12;A = {HHH, HHT, HTH, THH, TTH} B = {HHH, HTH, THH, TTH} C = {HHH independent? Explain. BC = {HHH, HTH}, so P(BC) = 1/4. That is equal to P(B)P(C), so B and C are independent

  2. Physiological properties and factors affecting migration of neural precursor cells in the adult olfactory bulb

    E-Print Network [OSTI]

    Darcy, Daniel Paul

    2007-01-01

    primary hypothesis that AMPAR-mediated inhibition of migrationprimary mediator between AMPARs and the reduction of NPC migration.Migration by Ca 2+ - permeable AMPA Receptors. ” The dissertation author is the primary

  3. Development of Diagnostic Rules for a Dry Bulb Economizer Mixed Air Loop 

    E-Print Network [OSTI]

    Underwood, D.

    1990-01-01

    in new situations such as HVAC diagnostics. The Army has developed standard HVAC system configurations, thus facilitating development of knowledge bases for those systems. This paper describes the development of if-then-else rules which make up part of a...

  4. Studying some mechanical properties of MgO with used neon bulb glass

    SciTech Connect (OSTI)

    Issa, Tarik Talib; Khaleel, Saba Mahdi; Abdul Kareem, Noura Ammar

    2013-12-16

    Ceramic compact of MgO +WT% of UNBG were sintered at different sintering temperature (700, 900, 1100, 1300)°c, under static air for 3 hours. X-ray diffraction and some mechanical properties were conducted. The maximum sintered density, compression; fracture strength and hardness were indicated for the compilation of MgO ?20 WT % UNBG, sintered at 1300 °c.

  5. Labeling energy cost on light bulbs lowers implicit discount rates Jihoon Min a

    E-Print Network [OSTI]

    Michalek, Jeremy J.

    consumption. A transition to alternative energy-efficient technologies could reduce this energy consumption of five, lowering barriers to adoption of energy efficient alternatives with higher up-front costs., 1980), uncertainty in the future price of electricity or other fuels, low priority of energy issues

  6. Westinghouse Pays $50,000 Civil Penalty to Resolve Light Bulb...

    Energy Savers [EERE]

    general service fluorescent and medium base compact fluorescent lamps that used more energy than permitted by law. This case reflects DOE's renewed commitment to enforce the...

  7. Consumer Light Bulb Changes: Briefing and Resources for Media and Retailers

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustmentsShirleyEnergyTher i n c i p aDepartmentEnergy comparing LEDCSAC CharterConsumer

  8. DOE Requires Westinghouse to Cease Sales of Two Light Bulb Models and

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:FinancingPetroleum Based| Department ofRefrigeratorsDepartmentEP9425Violating Minimum

  9. DOE Withdraws the Energy Star Label from 34 Compact Fluorescent Light Bulbs

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:FinancingPetroleum Based| Department8, 2015 GATEWAY Takes 9. TechnologyDOE Web| Department of

  10. Evaluation Helps Program Increase Sales of Energy Saving Light Bulbs Among

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:FinancingPetroleum12, 2015 InfographiclighbulbsDepartmentDeveloping new measuresEstimated |Women |

  11. What Light Bulbs Do You Use in Your Home? | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousMathematics And Statistics » USAJobs SearchAMERICA'S FUTURE.Projects atWeRenewableDoes the SunIs YourLight

  12. Which Bulb Is Right for You? (High-Resolution EPS Billboard) | Department

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousMathematics And Statistics » USAJobs SearchAMERICA'S FUTURE.Projects atWeRenewableDoesOffshore Windof

  13. Which Bulb Is Right for You? (High-Resolution JPG Billboard) | Department

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousMathematics And Statistics » USAJobs SearchAMERICA'S FUTURE.Projects atWeRenewableDoesOffshore Windofof

  14. Which Bulb Is Right for You? (Low-Resolution JPG Billboard) | Department of

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousMathematics And Statistics » USAJobs SearchAMERICA'S FUTURE.Projects atWeRenewableDoesOffshore

  15. Westinghouse Pays $50,000 Civil Penalty to Resolve Light Bulb Efficiency

    Energy Savers [EERE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIX E LIST OFAMERICA'S FUTURE. regulatorsEnergy InformationWestWestern

  16. A Winning Light Bulb With the Potential to Save the Nation Billions |

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustmentsShirley Ann JacksonDepartment of EnergyResearchers atDay 12: Drive5Leadership at PNNL |

  17. Buying the Perfect Energy-Efficient Light Bulb in 5 Easy Steps | Department

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustmentsShirley Ann JacksonDepartment|Marketing, LLCEfficiency | DepartmentEnergyof Energy Shopping

  18. Consumer Light Bulb Changes: Briefing and Resources for Media and Retailers

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustmentsShirleyEnergy A plug-in electric vehicle (PEV)Day-June 22,FresnoSky)Nuclear8Under| Department of

  19. Rise and Shine: Lighting the World with 10 Billion LED Bulbs | Department

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE: Alternative Fuels Data CenterFinancialInvesting inServicesRecoveryRhode Island Schools

  20. Clusters and halos in light nuclei

    E-Print Network [OSTI]

    Thomas Neff

    2012-10-15

    The fermionic molecular dynamics approach uses Gaussian wave packets as single-particle basis states. Many-body basis states are Slater determinants projected on parity, angular momentum and total linear momentum. The wave-packet basis is very flexible - FMD contains harmonic oscillator shell model and Brink-type cluster states as special cases. The parameters of the wave packets are obtained by variation. A realistic effective interaction derived from the Argonne V18 interaction by means of the unitary correlation operator method is employed. We discuss the fully microscopic calculation of the 3He(alpha,gamma)7Be capture reaction within the FMD approach. The model space contains frozen cluster configurations at large distances and polarized configurations in the interaction region. The polarized configurations are essential for a successful description of the 7Be bound state properties and for the S- and D-wave scattering states. The calculated cross section agrees well with recent measurements regarding both the absolute normalization and the energy dependence. We also discuss the structure of the cluster states, including the famous Hoyle state, in 12C. From the two-body densities we conclude that the Hoyle state has a spatially extended triangular alpha-cluster structure, whereas the third 0+ state features a chain-like obtuse triangle structure. We also calculate the N hbar Omega decomposition of our wave functions to illuminate the challenges of no-core shell model calculations for these cluster states.

  1. Saturn's moon rhea sports a dusty halo

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust, High-ThroughputUpcoming ReleaseSecurity Administration winsSarah L.7: Prof.

  2. Demonstration Assessment of Light Emitting Diode (LED) Residential Downlights and Undercabinet Lights in the Lane County Tour of Homes, Eugene, Oregon

    SciTech Connect (OSTI)

    Ton, My K.; Richman, Eric E.; Gilbride, Theresa L.

    2008-11-10

    In August 2008 the Pacific Northwest National Laboratory (PNNL) conducted a light emitting diode (LED) residential lighting demonstration project for the U.S. Department of Energy (DOE), Office of Building Technologies, as part of DOE’s Solid State Lighting (SSL) Technology Demonstration Gateway Program. Two lighting technologies, an LED replacement for downlight lamps (bulbs) and an LED undercabinet lighting fixture, were tested in the demonstration which was conducted in two homes built for the 2008 Tour of Homes in Eugene, Oregon. The homes were built by the Lane County Home Builders Association (HBA), and Future B Homes. The Energy Trust of Oregon (ETO) also participated in the demonstration project. The LED downlight product, the LR6, made by Cree LED Lighting Solutions acts as a screw-in replacement for incandescent and halogen bulbs in recessed can downlights. The second product tested is Phillips/Color Kinetics’ eW® Profile Powercore undercabinet fixture designed to mount under kitchen cabinets to illuminate the countertop and backsplash surfaces. Quantitative and qualitative measurements of light performance and electrical power usage were taken at each site before and after initially installed halogen and incandescent lamps were replaced with the LED products. Energy savings and simple paybacks were also calculated and builders who toured the homes were surveyed for their responses to the LED products. The LED downlight product drew 12 Watts of power, cutting energy use by 82% compared to the 65W incandescent lamp and by 84% compared to the 75W halogen lamp. The LED undercabinet fixture drew 10 watts, cutting energy use by 83% to 90% compared to the halogen product, which was tested at two power settings: a low power 60W setting and a high power 105W setting. The LED downlight consistently provided more light than the halogen and incandescent lamps in horizontal measurements at counter height and floor level. It also outperformed in vertical illuminance measurements taken on the walls, indicating better lateral dispersion of the light. The undercabinet fixture’s light output was midway between the low and high power halogen undercabinet fixture light outputs (35.8 foot candle versus 13.4 fc and 53.4 fc) but it produced a more uniform light (max/min ratio of 7.0 versus 10.8). The color correlated temperature (CCT, the blue or yellowness) of the LED light correlated well with the halogen and incandescent lights (2675 K vs 2700 K). The color rendering of the LED downlight also correlated well at 92 CRI compared to 100 CRI for the halogen and incandescent lamps. The LED undercabinet fixture had measures of 2880 K CCT and 71 CRI compared to the 2700 K and 100 CRI scores for the halogen undercabinet fixture. Builders who toured the homes were surveyed; they gave the LED downlight high marks for brightness, said the undercabinet improved shadows and glare and said both products improved overall visibility, home appearance, and home value. Paybacks on the LED downlight ranged from 7.6 years (assuming electricity cost of 11 c/kWh) to 13.5 years (at 5C/kWh). Paybacks on the LED undercabinet fixture in a new home ranged from 4.4 years (11c/kWh electricity) to 7.6 years (5c/kWh) based on product costs of $95 per LED downlight and $140 per LED undercabinet fixture at 3 hrs per day of usage for the downlight and 2 hrs per day for the undercabinet lighting.

  3. Investigating the Biosynthesis of Halogenated Meroterpenoid Natural Products from Marine Actinomycetes

    E-Print Network [OSTI]

    Winter, Jaclyn Marie

    2010-01-01

    0.25 M lithium sulfate 0.2 M calcium acetate 0.2 M calciumlithium nitrate none none none none none none 0.3 M ammonium acetate

  4. Investigating the biosynthesis of halogenated meroterpenoid natural products from marine actinomycetes

    E-Print Network [OSTI]

    Winter, Jaclyn Marie

    2010-01-01

    0.25 M lithium sulfate 0.2 M calcium acetate 0.2 M calciumlithium nitrate none none none none none none 0.3 M ammonium acetate

  5. Analysis and Characterization of Halogenated Transformation Products of Pharmaceuticals and Personal Care Products in Wastewater Effluent

    E-Print Network [OSTI]

    Bulloch, Daryl Neil

    2013-01-01

    L) in advanced primary wastewater treatment effluent treatedat an advanced primary wastewater treatment plant as finalat an advanced primary wastewater treatment plant as final

  6. Halogen-Based Plasma Etching of Novel Field-Effect Transistor Gate Materials

    E-Print Network [OSTI]

    Kiehlbaugh, Kasi Michelle

    2009-01-01

    access to the pumps inside for maintenance and repair. Afterand easy maintenance. The inlet to each mechanical pump was

  7. Processes for preparing carbon fibers using sulfur trioxide in a halogenated solvent

    DOE Patents [OSTI]

    Patton, Jasson T.; Barton, Bryan E.; Bernius, Mark T.; Chen, Xiaoyun; Hukkanen, Eric J.; Rhoton, Christina A.; Lysenko, Zenon

    2015-12-29

    Disclosed here are processes for preparing carbonized polymers (preferably carbon fibers), comprising sulfonating a polymer with a sulfonating agent that comprises SO.sub.3 dissolved in a solvent to form a sulfonated polymer; treating the sulfonated polymer with a heated solvent, wherein the temperature of the solvent is at least 95.degree. C.; and carbonizing the resulting product by heating it to a temperature of 500-3000.degree. C. Carbon fibers made according to these methods are also disclosed herein.

  8. Supramolecular self-assembled network formation containing NBr halogen bonds in physisorbed overlayers

    E-Print Network [OSTI]

    Brewer, Adam Y.; Sacchi, Marco; Parker, Julia E.; Truscott, Chris L.; Jenkins, Steve; Clarke, Stuart M.

    2014-08-05

    the physicochemical properties of molecular solids4 via complementary interactions between the constituent mole- cules. Similar principles have been utilised in the design of two-dimensional (2D) physisorbed co-layers. Typically, hydro- gen bonding is the interaction... of the surface unit cell, relative to the much stronger adsorbate–adsorbate interactions.32,41 Therefore in the first set of calculations we have optimized the structure of the commensurate and non-commensurate co- layer without including the substrate...

  9. Halogen-Based Plasma Etching of Novel Field-Effect Transistor Gate Materials

    E-Print Network [OSTI]

    Kiehlbaugh, Kasi Michelle

    2009-01-01

    for the main etch step: Adding fluorine-bearing species tothe main etch. It was included as an alternative F-bearing

  10. Separating the Influence of Halogen and Climate Changes on Ozone Recovery in the Upper Stratosphere

    E-Print Network [OSTI]

    causes ozone destruction by enhancing production of water vapor via methane oxidation. Additionally. Including potential climate-induced stratospheric water vapor increases, the ozone change relative to 1980 depletion chemistry, and therefore indirectly leading to more ozone. Increases in methane directly affect

  11. Treatment and prevention systems for acid mine drainage and halogenated contaminants

    DOE Patents [OSTI]

    Jin, Song (Fort Collins, CO); Fallgren, Paul H. (Laramie, WY); Morris, Jeffrey M. (Laramie, WY)

    2012-01-31

    Embodiments include treatments for acid mine drainage generation sources (10 perhaps by injection of at least one substrate (11) and biologically constructing a protective biofilm (13) on acid mine drainage generation source materials (14). Further embodiments include treatments for degradation of contaminated water environments (17) with substrates such as returned milk and the like.

  12. Reactive Halogens in the Marine Boundary Layer (RHaMBLe): the tropical North Atlantic experiments

    E-Print Network [OSTI]

    2010-01-01

    close to or East of the Canary Islands, before arriving atpassing near to the Canary Islands on its way to Cape Verde.passing close to the Canary islands before approaching Cape

  13. THERMAL RATE CONSTANTS, ENERGY DEPENDENCE AND ISOTOPE EFFECT FOR LASER INITIATED HALOGEN-HYGRO-GENHALIDE REACTIONS

    E-Print Network [OSTI]

    Mei, C.-C.

    2011-01-01

    vs 10 IT ..•..••. Velocity dependence of the reaction crossIII-II. Velocity dependence of the reaction cross section crthermal reaction, the ratio of the rotational velocity of

  14. Halogen-elimination photochemistry and oxygen-activation chemistry of late transition-metal complexes

    E-Print Network [OSTI]

    Teets, Thomas S. (Thomas Sebastian)

    2012-01-01

    Multi-electron reaction chemistry, from both ground- and excited-state species, is at the heart of many topics in renewable energy and catalysis. In this thesis, two classes of reactions central to the themes of energy ...

  15. The Halogenation of Oils with Special Attention to the Method of Wijs

    E-Print Network [OSTI]

    Rhodes, Edmund Oliver

    1913-05-15

    of experiments in which varying time was used, 44 Eh c CO o a •H Eh «.H O +> O O , 3 C IH EH o o o a a $ S to o CO as will be noted from time to time in this paper while explaining the various tables. Following the completion of Table Ho. I, a series of experiments represented by Tables II, III, IV and V...

  16. Remedial extraction and catalytic hydrodehalogenation for treatment of soils contaminated by halogenated hydrophobic organic compounds 

    E-Print Network [OSTI]

    Wee, Hun Young

    2009-05-15

    for the extraction of 1,2,4,5-tetrachlorobenzne (TeCB) or pentachlorophenol (PCP) from contaminated soil. Palladium-catalyzed hydrodehalogenation (HDH) was applied for destroying TeCB or PCP in mixtures of water and ethanol in a batch mode. The experimental results...

  17. Analysis and Characterization of Halogenated Transformation Products of Pharmaceuticals and Personal Care Products in Wastewater Effluent

    E-Print Network [OSTI]

    Bulloch, Daryl Neil

    2013-01-01

    emerging contaminants in sewage sludge. Trac-Trends Anal.mass spectrometry in sewage sludge from the Spanish area of

  18. Some cultural practices affecting bulb rot, plant and floral development, and seed yield of the White Grano onion 

    E-Print Network [OSTI]

    Enzie, Joseph Vincent

    1955-01-01

    Public Buildings Leading by Example Philip Gates, CEM, CMVP, EIT Energy Manager 1 ESL-KT-13-12-27 CATEE 2013: Clean Air Through Energy Efficiency Conference, San Antonio, Texas Dec. 16-18 2 H ow to be gin ? ESL-KT-13-12-27 CATEE 2013: Clean Air... solution • 6,500 devices • $200K annual savings Pool Pump Control • Stop over-circulating • 24 Public Pools • $70K annual savings LED Street Lighting • Replace high wattage fixt. • 25,000 fixtures • $, kWh annually Chillers & DX Units • Eff. equip. w...

  19. MODERATE C IV ABSORBER SYSTEMS REQUIRE 10{sup 12} M{sub Sun} DARK MATTER HALOS AT z {approx} 2.3: A CROSS-CORRELATION STUDY OF C IV ABSORBER SYSTEMS AND QUASARS IN SDSS-III BOSS DR9

    SciTech Connect (OSTI)

    Vikas, Shailendra; Wood-Vasey, W. Michael; Lundgren, Britt; Ross, Nicholas P.; Myers, Adam D.; AlSayyad, Yusra; York, Donald G.; Schneider, Donald P.; Brinkmann, J.; Bizyaev, Dmitry; Brewington, Howard; Malanushenko, Elena; Malanushenko, Viktor; Oravetz, Daniel; Pan, Kaike; Snedden, Stephanie; Ge, Jian; Muna, Demitri; Paris, Isabelle; Petitjean, Patrick; and others

    2013-05-01

    We measure the two-point cross-correlation function of C IV absorber systems and quasars, using spectroscopic data from the Sloan Digital Sky Survey III Baryon Oscillation Spectroscopic Survey (BOSS; Data Release 9). The 19,701 quasars and 6149 C IV ''moderate'' absorbers, 0.28 A < rest-frame equivalent width (EW) < 5 A, in our study cover a redshift range of 2.1 < z < 2.5 over 3300 deg{sup 2} and represent a factor of two increase in sample size over previous investigations. We find a correlation scale length and slope of the redshift-space cross-correlation function of s{sub 0} = 8.46 {+-} 1.24 Mpc, {gamma} = 1.68 {+-} 0.19, in the redshift-space range 10 < s < 100 Mpc. We find a projected cross-correlation function of C IV absorption systems and quasars of r{sub 0} = 7.76 {+-} 2.80 Mpc, {gamma} = 1.74 {+-} 0.21. We measure the combined quasar and C IV bias to be b{sub QSO} b{sub C{sub IV}} = 8.81 {+-} 2.28. Using an estimate of b{sub QSO} from the quasar auto-correlation function we find b{sub CIV} = 2.38 {+-} 0.62. This b{sub CIV} implies that EW > 0.28 A C IV absorbers at z {approx} 2.3 are typically found in dark matter halos that have masses {>=}10{sup 11.3}-10{sup 13.4} M{sub Sun} at that redshift. The complete BOSS sample will triple the number of both quasars and absorption systems and increase the power of this cross-correlation measurement by a factor of two.

  20. Halo Nucleus Be11: A Spectroscopic Study via Neutron Transfer

    E-Print Network [OSTI]

    Schmitt, K. T.; Jones, K. L.; Bey, A.; Ahn, S.; Bardayan, D. W.; Bardayan, D. W.; Blackmon, J. C.; Brown, S. M.; Chae, K. Y.; Chipps, K. A.; Cizewski, J. A.; Hahn, K. I.; Kolata, J. J.; Kozub, R. L.; Liang, J. F.; Matei, C.; Matoš, M.; Matyas, D.; Moazen, B.; Nesaraja, C.; Wilson, Graham Wallace

    2012-05-08

    the final state resembles the ground state of the core coupled to a neutron in a particular single-particle state. This formalism relies on nuclear scattering potentials to describe the interaction between the two nuclei in the entrance and exit channels...), or insufficiently constrained theo- retical analysis. To help resolve this situation, an extensive series of measurements have been made using a primary beam of 10 Be ions. Elastic- and inelastic-scattering data were ob- tained simultaneously with neutron transfer...

  1. On the Average Comoving Number Density of Halos

    E-Print Network [OSTI]

    A. Del Popolo

    2006-09-05

    I compare the numerical multiplicity function given in Yahagi, Nagashima & Yoshii (2004) with the theoretical multiplicity function obtained by means of the excursion set model and an improved version of the barrier shape obtained in Del Popolo & Gambera (1998), which implicitly takes account of total angular momentum acquired by the proto-structure during evolution and of a non-zero cosmological constant. I show that the multiplicity function obtained in the present paper, is in better agreement with Yahagi, Nagashima & Yoshii (2004) simulations than other previous models (Sheth & Tormen 1999; Sheth, Mo & Tormen 2001; Sheth & Tormen 2002; Jenkins et al. 2001) and that differently from some previous multiplicity function models (Jenkins et al. 2001; Yahagi, Nagashima & Yoshii 2004) it was obtained from a sound theoretical background.

  2. Declarative Modeling and Bayesian Inference of Dark Matter Halos

    E-Print Network [OSTI]

    Kronberger, Gabriel

    2013-01-01

    Probabilistic programming allows specification of probabilistic models in a declarative manner. Recently, several new software systems and languages for probabilistic programming have been developed on the basis of newly developed and improved methods for approximate inference in probabilistic models. In this contribution a probabilistic model for an idealized dark matter localization problem is described. We first derive the probabilistic model for the inference of dark matter locations and masses, and then show how this model can be implemented using BUGS and Infer.NET, two software systems for probabilistic programming. Finally, the different capabilities of both systems are discussed. The presented dark matter model includes mainly non-conjugate factors, thus, it is difficult to implement this model with Infer.NET.

  3. DARK MATTER HALO PROFILES OF MASSIVE CLUSTERS: THEORY VERSUS...

    Office of Scientific and Technical Information (OSTI)

    of 2 Multiplication-Sign 10sup 12 to 2 Multiplication-Sign 10sup 15 h sup -1 Msub Sun and a redshift range of z 0-2, while satisfying the associated requirements of...

  4. Rubidium in Metal-Deficient Disk and Halo Stars

    E-Print Network [OSTI]

    Jocelyn Tomkin; David L. Lambert

    1999-05-13

    We report the first extensive study of stellar Rb abundances. High-resolution spectra have been used to determine, or set upper limits on, the abundances of this heavy element and the associated elements Y, Zr, and Ba in 44 dwarfs and giants with metallicities spanning the range -2.0 <[Fe/H] < 0.0. In metal-deficient stars Rb is systematically overabundant relative to Fe; we find an average [Rb/Fe] of +0.21 for the 32 stars with [Fe/H] < -0.5 and measured Rb. This behavior contrasts with that of Y, Zr, and Ba, which, with the exception of three new CH stars (HD 23439A and B and BD +5 3640), are consistently slightly deficient relative to Fe in the same stars; excluding the three CH stars, we find the stars with [Fe/H] < -0.5 have average [Y/Fe], [Zr/Fe], and [Ba/Fe] of --0.19 (24 stars), --0.12 (28 stars), and --0.06 (29 stars), respectively. The different behavior of Rb on the one hand and Y, Zr, and Ba on the other can be attributed in part to the fact that in the Sun and in these stars Rb has a large r-process component while Y, Zr, and Ba are mostly s-process elements with only small r-process components. In addition, the Rb s-process abundance is dependent on the neutron density at the s-processing site. Published observations of Rb in s-process enriched red giants indicate a higher neutron density in the metal-poor giants. These observations imply a higher s-process abundance for Rb in metal-poor stars. The calculated combination of the Rb r-process abundance, as estimated for the stellar Eu abundances, and the s-process abundance as estimated for red giants accounts satisfactorily for the observed run of [Rb/Fe] with [Fe/H].

  5. Transport of charged dust grains into the galactic halo

    E-Print Network [OSTI]

    Khoperskov, S A

    2014-01-01

    We develop a 3D dynamical model of dust outflows from galactic discs. The outflows are initiated by multiple SN explosions in a magnetized interstellar medium (ISM) with a gravitationally stratified density distribution. Dust grains are treated as particles in cells interacting collisionally with gas, and forced by stellar radiation of the disc and Lorenz force. We show that magnetic field plays a crucial role in accelerating the charged dust grains and expelling them out of the disc: in 10--20~Myr they can be elevated at distances up to 10~kpc above the galactic plane. The dust-to-gas ratio in the outflowing medium varies in the range $5 \\cdot 10^{-4} - 5 \\cdot 10^{-2}$ along the vertical stream. Overall the dust mass loss rate depends on the parameters of ISM and may reach up to $3\\times 10^{-2}$~\\Msun~yr$^{-1}$

  6. DARK MATTER HALO PROFILES OF MASSIVE CLUSTERS: THEORY VERSUS OBSERVATIONS

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing BacteriaConnect Collidertransfer (Journal Article) | SciTech Connect(Journal

  7. The Dependence of Subhalo Abundance on Halo Concentration (Journal Article)

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail. (Conference)Feedback SystemGimbaledM-PACEConnectTheoretical and Experimental|

  8. The Dependence of Subhalo Abundance on Halo Concentration (Journal Article)

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail. (Conference)Feedback SystemGimbaledM-PACEConnectTheoretical and Experimental||

  9. PROJECT PROFILE: Halo Industries, Inc. (Incubator 10) | Department of

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE: Alternative Fuelsof EnergyAprilEnergy EEREPlateauFolsom Labs (Incubator 10)

  10. Kinetic model for predicting the concentrations of active halogens species in chlorinated saline cooling waters. Final report

    SciTech Connect (OSTI)

    Haag, W.R.; Lietzke, M.H.

    1981-08-01

    A kinetic model has been developed for describing the speciation of chlorine-produced oxidants in seawater as a function of time. The model is applicable under a broad variety of conditions, including all pH range, salinities, temperatures, ammonia concentrations, organic amine concentrations, and chlorine doses likely to be encountered during power plant cooling water chlorination. However, the effects of sunlight are not considered. The model can also be applied to freshwater and recirculating water systems with cooling towers. The results of the model agree with expectation, however, complete verification is not feasible at the present because analytical methods for some of the predicted species are lacking.

  11. Kinetic Modeling of Halogen-Based Plasma Etching of Complex Oxide Films and its Application to Predictive Feature Profile Simulation

    E-Print Network [OSTI]

    Marchack, Nathan

    2012-01-01

    Guidelines A.1.1. Emergency Shut Down Procedures I. In caseGuidelines A.2.1. Emergency Shut Down Procedures 1. Turn offProcedure A.3.1. Emergency Shut Down Procedures I. In case

  12. Experimental and Computational Study of Flame Inhibition Mechanisms of Halogenated Compounds in C1-C3 Alkanes Flames 

    E-Print Network [OSTI]

    Osorio Amado, Carmen H

    2013-07-30

    has been found to meet all of the exigent criteria. Further progress in this research requires fundamental combustion knowledge that can help us understand the unique performance of Halon 1301, to prevent this search from becoming a tedious trial...

  13. Fluids and halogens at the diagenetic-metamorphic boundary: evidence from veins in continental basins, western Norway

    E-Print Network [OSTI]

    Svensen, Henrik

    basins, western Norway H. SVENSEN1 , B. JAMTVEIT1 , D. A. BANKS2 AND D. KARLSEN1 1 Department of Geology, University of Oslo, Blindern, Oslo, Norway; 2 School of Earth Sciences, University of Leeds, Leeds, UK, Kvamshesten and Solund basins) in western Norway. These include calcite-, quartz- and epidote-dominated veins

  14. Recovery of Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) from Ralstonia eutropha cultures with non-halogenated solvents

    E-Print Network [OSTI]

    Riedel, Sebastian L.

    Reduced downstream costs, together with high purity recovery of polyhydroxyalkanoate (PHA), will accelerate the commercialization of high quality PHA-based products. In this work, a process was designed for effective ...

  15. Two versatile cofactors, flavin adenine dinucleotide and non-heme iron, involved in DNA repair and natural product halogenation

    E-Print Network [OSTI]

    Wong, Cintyu

    2009-01-01

    Cofactors assist enzymes with a variety of complex chemistries. Two versatile cofactors, flavin adenine dinucleotide (FAD) and non-heme iron, together with molecular oxygen as an oxidizing agent, perform a wide array of ...

  16. Kinetic Modeling of Halogen-Based Plasma Etching of Complex Oxide Films and its Application to Predictive Feature Profile Simulation

    E-Print Network [OSTI]

    Marchack, Nathan

    2012-01-01

    S.F. “Area Selective Atomic Layer Deposition by Microcontactarea-selective atomic layer deposition." Advanced Materialsof Al2O3 using atomic layer deposition." Applied Physics

  17. Kinetic Modeling of Halogen-Based Plasma Etching of Complex Oxide Films and its Application to Predictive Feature Profile Simulation

    E-Print Network [OSTI]

    Marchack, Nathan

    2012-01-01

    Applied Physics Letters 94(4). Pourbaix, M. (1976). "SOMEEllingham 1944) and the Pourbaix diagram (plot of voltageelectrochemical system). (Pourbaix 1976) However, for the

  18. Kinetic Modeling of Halogen-Based Plasma Etching of Complex Oxide Films and its Application to Predictive Feature Profile Simulation

    E-Print Network [OSTI]

    Marchack, Nathan

    2012-01-01

    958-963. Chae, H. , S. A. Vitale, et al. (2003). "Silicon381-387. Chae, H. , S. A. Vitale, et al. (2003). "SiliconPhysics 57(2): 952-959. Vitale, S. A. , H. Chae, et al. (

  19. Gas Phase Reactions between Fuel Molecules and Halogens: A Review of the Reaction between Atomic Chlorine and Ammonia

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

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

  20. The antennal lobe (AL) of an insect is the functional analog of the olfactory bulb in mammals. The first-level synaptic interaction between large numbers

    E-Print Network [OSTI]

    Menzel, Randolf - Institut für Biologie

    glomeruli, the medial (m) group with seven glomeruli, the ventroposterior (vp) group with 70 glomeruli, and the posterior (p) group with seven glomeruli (Fig. 43.1A). Glomeruli are the anatomical and func- tional units Microcircuits different groups of glomeruli of the AL (Fig. 43.1), the dorsoanterior (da) group with 70

  1. Essays on Environmental and Resource Economics

    E-Print Network [OSTI]

    Toledo, Chantal Nathalie

    2013-01-01

    energy efficient light bulb at home are more likely to take-or an energy efficient light bulb at home increases theenergy efficient light bulb at home are more likely to take-

  2. Shut Down Schedule Optimization with Outdoor Humidity Level 

    E-Print Network [OSTI]

    Chen, H.; Deng, S.; Turner, W. D.; Claridge, D. E.; Clingenpeel, K.

    2006-01-01

    been selected. This wet bulb temperature corresponds to the wet bulb temperature at our desired room condition. The 63°F wet bulb temperature limit will make sure that the air entering the building has less enthalpy than the desired room...

  3. General Service LED Lamps

    Broader source: Energy.gov [DOE]

    A U.S. DOE SSL technology fact sheet that compares general service LED light bulbs with incandescent and CFL bulbs.

  4. Rapid energy savings in London's households to mitigate an energy crisis

    E-Print Network [OSTI]

    Julien, Aurore; Barrett, Mark; Croxford, Ben

    2011-01-01

    low energy light bulbs in the whole home Unplug my phoneall low energy light bulbs in t he whole home S ch off all

  5. Entergy Arkansas- Agricultural Energy Solutions Program Rebates

    Broader source: Energy.gov [DOE]

    The Presecriptive Option offers predetermined incentives on a wide variety of energy efficiency measures including Compact Flourescent Light Bulbs and high performance flourescent bulb replacemen...

  6. Evaluation Helps Program Increase Sales of Energy Saving Light...

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

    Program Increase Sales of Energy Saving Light Bulbs Among Women Evaluation Helps Program Increase Sales of Energy Saving Light Bulbs Among Women This document, from the Wisconsin...

  7. Evaluation Helps Program Increase Sales of Energy Saving Light...

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

    Evaluation Helps Program Increase Sales of Energy Saving Light Bulbs Among Women Evaluation Helps Program Increase Sales of Energy Saving Light Bulbs Among Women This document,...

  8. Tax Credits, Rebates & Savings | Department of Energy

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

    install energy efficiency measures in Xcel service territory. Rebates are available for evaporative cooling systems, LED light bulbs, and CFL light bulbs. All equipment must meet...

  9. Energy efficient synthesis of boranes

    DOE Patents [OSTI]

    Thorn, David L (Los Alamos, NM); Tumas, William (Los Alamos, NM); Schwarz, Daniel E (Los Alamos, NM); Burrell, Anthony K (Los Alamos, NM)

    2012-01-24

    The reaction of halo-boron compounds (B--X compounds, compounds having one or more boron-halogen bonds) with silanes provides boranes (B--H compounds, compounds having one or more B--H bonds) and halosilanes. Inorganic hydrides, such as surface-bound silane hydrides (Si--H) react with B--X compounds to form B--H compounds and surface-bound halosilanes. The surface bound halosilanes are converted back to surface-bound silanes electrochemically. Halo-boron compounds react with stannanes (tin compounds having a Sn--H bond) to form boranes and halostannanes (tin compounds having a Sn--X bond). The halostannanes are converted back to stannanes electrochemically or by the thermolysis of Sn-formate compounds. When the halo-boron compound is BCl.sub.3, the B--H compound is B.sub.2H.sub.6, and where the reducing potential is provided electrochemically or by the thermolysis of formate.

  10. Energy efficient synthesis of boranes

    DOE Patents [OSTI]

    Thorn, David L. (Los Alamos, NM); Tumas, William (Los Alamos, NM); Schwarz, Daniel E. (Los Alamos, NM); Burrell, Anthony K. (Los Alamos, NM)

    2010-11-23

    The reaction of halo-boron compounds (B--X compounds, compounds having one or more boron-halogen bonds) with silanes provides boranes (B--H compounds, compounds having one or more B--H bonds) and halosilanes. Inorganic hydrides, such as surface-bound silane hydrides (Si--H) react with B--X compounds to form B--H compounds and surface-bound halosilanes. The surface bound halosilanes are converted back to surface-bound silanes electrochemically. Halo-boron compounds react with stannanes (tin compounds having a Sn--H bond) to form boranes and halostannanes (tin compounds having a Sn--X bond). The halostannanes are converted back to stannanes electrochemically or by the thermolysis of Sn-formate compounds. When the halo-boron compound is BCl.sub.3, the B--H compound is B.sub.2H.sub.6, and where the reducing potential is provided electrochemically or by the thermolysis of formate.

  11. STUDIES ON ZINC NODULES ELECTRODEPOSITED FROM ACID ELECTROLYTES

    E-Print Network [OSTI]

    Anderson, R.

    2011-01-01

    LBL Workshop on the Electrochemistry of Zinc/Halogen Bat-and E. Cairns, "The Electrochemistry Zinc Electrode," inon the Proceed- of Electrochemistry Zinc/Halogen Batteries,

  12. The translucency of dental composites investigated by UV-VIS spectroscopy

    SciTech Connect (OSTI)

    Dumitrescu, L. Silaghi; Pastrav, O.; Prejmerean, C.; Prodan, D.; Boboia, S.; Codruta, S.; Moldovan, M.

    2013-11-13

    Translucency is the property of a material to partially transmit and diffuse incident light, and can be described as a partial opacity or a state between complete opacity and complete transparency. The purpose of this study is to evaluate the translucency index of resin composites according to their chemical structure and to the light source used for curing. Our study was achieved on four commercial composite samples (30 mm × 2 mm) cured with two different lamps (Optilux - halogen bulb and Ultralight - LED). Measurements were made with a UV-VIS spectrophotometer, and the reflection spectrum was recorded in the 380-770 nm region on white and black, compared with a SPECTRALON standard white. For all materials cured with the LED lamp on the glossy sides, the best results were given by Tetric Evo Ceram followed by Filtek Supreme, Restacril{sup RO} and Premise. The measurements made on samples cured with an Optilux lamp, to the smooth and rough sides of the samples, revealed that the highest index of translucency is provided by Tetric Evo Ceram on the smooth side, followed by Filtek Supreme, Restacril{sup RO} and Premises. We can say that the translucency of the composites is mostly determined by the chemical composition of the material, which is observed from transmittance values recorded for each sample, and by the source of radiation applied on the sample.

  13. EDDY RESOLVING NUTRIENT ECODYNAMICS IN THE GLOBAL PARALLEL OCEAN PROGRAM AND CONNECTIONS WITH TRACE GASES IN THE SULFUR, HALOGEN AND NMHC CYCLES

    SciTech Connect (OSTI)

    S. CHU; S. ELLIOTT

    2000-08-01

    Ecodynamics and the sea-air transfer of climate relevant trace gases are intimately coupled in the oceanic mixed layer. Ventilation of species such as dimethyl sulfide and methyl bromide constitutes a key linkage within the earth system. We are creating a research tool for the study of marine trace gas distributions by implementing coupled ecology-gas chemistry in the high resolution Parallel Ocean Program (POP). The fundamental circulation model is eddy resolving, with cell sizes averaging 0.15 degree (lat/long). Here we describe ecochemistry integration. Density dependent mortality and iron geochemistry have enhanced agreement with chlorophyll measurements. Indications are that dimethyl sulfide production rates must be adjusted for latitude dependence to match recent compilations. This may reflect the need for phytoplankton to conserve nitrogen by favoring sulfurous osmolytes. Global simulations are also available for carbonyl sulfide, the methyl halides and for nonmethane hydrocarbons. We discuss future applications including interaction with atmospheric chemistry models, high resolution biogeochemical snapshots and the study of open ocean fertilization.

  14. Grant Holder Research Organisation Project Title Grant Reference Peter Bernath University of York Satellite Observations of Halogen-Containing Molecules NE/I022663/1

    E-Print Network [OSTI]

    Grant Holder Research Organisation Project Title Grant Reference Peter Bernath University of York, Ice and Super-cooled Water Particles. NE/I023058/1 Gareth Chisham NERC British Antarctic Survey The University of Manchester Effects of a warming climate on the key organic carbon cycle processes

  15. Field test of a generic method for halogenated hydrocarbons: Semivost test at a chemical manufacturing facility. Final project report, August 1992-August 1993

    SciTech Connect (OSTI)

    McGaughey, J.F.; Bursey, J.T.; Merrill, R.G.

    1996-11-01

    The candidate methods for semivolatile organic compounds are SW-846 Sampling Method 0010 and Analytical Method 8270, which are applicable to stationary sources. Two field tests were conducted using quadruple sampling trains with dynamic spiking were performed according to the guidelines of EPA Method 301. The first field test was performed at a site with low levels of moisture. The second test reported here was conducted at a chemical manufacturing facility where chemical wastes were burned in a coal-fired boiler. Poor recoveries obtained for the spiked analytes at the second test were attributed to wet sorbent from the sampling train, use of methanol to effect complete transfer of wet sorbent from the sampling module, and use of extraction techniques which did not effect a complete separation of methylene chloride from methanol. A procedure to address problems with preparation of samples from Method 0010 is included in the report.

  16. Deoxybenzoin-Based Polyarylates as Halogen-Free Fire-Resistant Kenneth A. Ellzey, T. Ranganathan, Joseph Zilberman, E. Bryan Coughlin,*

    E-Print Network [OSTI]

    with high carbon monoxide emis- sion.7,8 Ideal flame-retardant polymers would possess high thermal stability, low combustion heat release rate, low total heat of combustion, and minimal release of toxic fumes. The use of nonhalogenated polymers that undergo significant carbonization upon heating is highly desirable

  17. Reactive halogens (BrO and OClO) detected in the plume of Soufrière Hills Volcano during an eruption hiatus

    E-Print Network [OSTI]

    Donovan, Amy; Tsanev, Vitchko; Oppenheimer, Clive; Edmonds, Marie

    2014-08-20

    column densities. The final week of measurements was characterized by lower wind speeds and clearer skies. Attempts to measure the ageing plume offshore on 17 April 2011 had limited success due to attenuation and the angle at which the measurements had...

  18. Fluid origins, paths, and fluid-rock reactions at convergent margins, using halogens, Cl stable isotopes, and alkali metals as geochemical tracers

    E-Print Network [OSTI]

    Wei, Wei

    2007-01-01

    20-40 mm/yr and the geothermal gradient is high, ~110°C/km,is 85 mm/yr and the geothermal gradient is ~10°C/km (TableRica subduction zone, the geothermal gradient is low and

  19. Fluid origins, paths, and fluid-rock reactions at convergent margins, using halogens, Cl stable isotopes, and alkali metals as geochemical tracers

    E-Print Network [OSTI]

    Wei, Wei

    2007-01-01

    0.89 ‰ at Nankai and Barbados, (e.g. Ransom et al. , 1995;to -7.8 ‰ at Nankai and Barbados (e.g. (Ransom et al. ,3.3.2; (2) smectite from Barbados (ODP Leg 110, 110-671B-51

  20. Safe Use of Isoflurane in Animal Care Research Isoflurane is a halogenated hydrocarbon that is commonly used as an animal anesthetic. Exposure to

    E-Print Network [OSTI]

    Jia, Songtao

    ; cough, sore throat, headache, drowsiness, and dizziness. The health effects from long term exposure

  1. ,,,"Incandescent","Standard Fluorescent","Compact Fluorescent","High-Intensity Discharge","Halogen"

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: AlternativeMonthly","10/2015"Monthly","10/2015" ,"Release7 Relative Standard Errors for Table 5.7;" " Unit:8977.8.38.

  2. ,,,"Incandescent","Standard Fluorescent","Compact Fluorescent","High-Intensity Discharge","Halogen"

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: AlternativeMonthly","10/2015"Monthly","10/2015" ,"Release7 Relative Standard Errors for Table 5.7;" "

  3. UBC Social Ecological Economic Development Studies (SEEDS) Student Report Ben Duenas, Chen Ling, Neona Chan, Yi Ru Soh

    E-Print Network [OSTI]

    categories: solvent/oil waste (halogenated, non- halogenated and oils), non-regulated contaminated solid, Neona Chan, Yi Ru Soh Quantifying Water Content for Non-halogenated Waste Solvents CHBE 464 March 24 Problem-Based Laboratory: Final Report Quantifying Water Content for Non-halogenated Waste Solvents March

  4. On the measurement of kinetic temperature in high redshift galactic halos

    E-Print Network [OSTI]

    Sergei A. Levshakov; Wilhelm W. Kegel

    1999-05-11

    We consider the deconvolution of the thermal and the turbulent profiles for a pair of ions with different atomic weights under the condition that the lines are formed in an absorbing medium with fluctuating density and velocity fields. Our method is based on the entropy-regularized minimization (ERM) procedure. From synthetic spectra we found that the CII and SiII lines can be used to estimate the mean (density weighted) kinetic temperature with a sufficiently high accuracy (of about 10%) in a rather wide range of the ionization parameter, -6 < log U < -2. This is a generalization of a previous result (Levshakov, Takahara and Agafonova 1999) where we did not account for density fluctuations.

  5. A Comparison of Copper Abundances in Globular Cluster and Halo Field Giant Stars

    E-Print Network [OSTI]

    Jennifer Simmerer; Christopher Sneden; Inese I. Ivans; Robert P. Kraft; Matthew D. Shetrone; Verne V. Smith

    2003-03-07

    We derive [Cu/Fe] for 117 giant stars in ten globular clusters (M3, M4, M5, M10, M13, M15, M71, NGC 7006, NCG 288, and NGC 362) and find that globular cluster Cu abundances appear to follow [Cu/Fe] trends found in the field. This result is interesting in light of recent work which indicates that the globular cluster Omega Centauri shows no trend in [Cu/Fe] with [Fe/H] over the abundance range -2.0 <[Fe/H]< -0.8. Of particular interest are the two clusters M4 and M5. While at a similar metallicity ([Fe/H] ~- 1.2), they differ greatly in some elemental abundances: M4 is largely overabundant in Si, Ba, and La compared to M5. We find that it is also overabundant in Cu with respect to M5, though this overabundance is in accord with [Cu/Fe] ratios found in the field.

  6. Synthetic Approaches to Skeletally Diverse Sultams Using Vinyl- and ?-Halo Benzenesulfonamides

    E-Print Network [OSTI]

    Jeon, KyuOk

    2012-08-31

    The development of new chemical methods to generate novel and diverse structures to probe chemical space is an important aspect of early phase drug discovery. Diversity-Oriented Synthesis (DOS) is a powerful strategy that ...

  7. Leakage Current and Dopant Activation Characterization of SDE/Halo CMOS Junctions with

    E-Print Network [OSTI]

    Schroder, Dieter K.

    by trap assisted and band-to-band tunneling. The reduced thermal budget of IRTP allows junction formation is described by high electron and hole recombination-generation in the end-of-range (EOR) damage layer enhanced/cm^) for high sub-junction doping due to band-to- band and trap-assisted tunnehng [1,2,3] compromises

  8. An Origin for Multi-Phase Gas in Galactic Winds and Halos

    E-Print Network [OSTI]

    Thompson, Todd A; Zhang, Dong; Weinberg, David

    2015-01-01

    The origin of high velocity cool gas seen in galactic winds remains unknown. Following Wang (1995), we argue that rapid radiative cooling in initially hot (10^7-10^8 K) thermally-driven outflows can produce fast neutral atomic and photoionized cool gas. Outflows with hot gas mass-loading factor relative to star formation rate of beta > 0.5 cool on scales ranging from the size of the host to tens of kpc. We provide scalings for the cooling radius r_cool, density, column density, emission measure, radiative efficiency, and cool gas velocity. At r_cool, the gas produces X-ray and then UV/optical line emission at velocities of hundreds to thousands of km/s with a total power bounded from above by the energy injection rate 0.01 L_star if the flow is powered by steady-state star formation with luminosity L_star. The wind is thermally and convectively unstable at and beyond r_cool. Thermal instability can amplify density fluctuations by a factor of ~100, potentially leading to a multi-phase medium. Cooled winds can ...

  9. Normal and outlying populations of the Milky Way stellar halo at [Fe/H] <–2

    SciTech Connect (OSTI)

    Cohen, Judith G.; Christlieb, Norbert; Thompson, Ian; McWilliam, Andrew; Shectman, Stephen; Reimers, Dieter; Wisotzki, Lutz; Kirby, Evan E-mail: N.Christlieb@lsw.uni-heidelberg.de E-mail: shec@obs.carnegiescience.edu E-mail: dreimers@hs.uni-hamburg.de E-mail: ekirby@uci.edu

    2013-11-20

    From detailed abundance analysis of >100 Hamburg/ESO candidate extremely metal-poor (EMP) stars we find 45 with [Fe/H] < –3.0 dex. We identify a heretofore unidentified group: Ca-deficient stars with sub-solar [Ca/Fe] ratios and the lowest neutron-capture abundances; the Ca-deficient group comprises ?10% of the sample, excluding Carbon stars. Our radial velocity distribution shows that the carbon-enhanced stars with no s-process enhancements, CEMP-no, and which do not show C{sub 2} bands are not preferentially binary systems. Ignoring Carbon stars, approximately 15% of our sample are strong (?5?) outliers in one or more elements between Mg and Ni; this rises to ?19% if very strong (?10?) outliers for Sr and Ba are included. Examples include: HE0305–0554 with the lowest [Ba/H] known; HE1012–1540 and HE2323–0256, two (non-velocity variable) C-rich stars with very strong [Mg,Al/Fe] enhancements; and HE1226–1149, an extremely r-process rich star.

  10. Cold dark matter halos in Multi-coupled Dark Energy cosmologies: structural and statistical properties

    E-Print Network [OSTI]

    Baldi, Marco

    2014-01-01

    The recently proposed Multi-coupled Dark Energy (McDE) scenario - characterised by two distinct Cold Dark Matter (CDM) particle species with opposite couplings to a Dark Energy scalar field - introduces a number of novel features in the small-scale dynamics of cosmic structures, most noticeably the simultaneous existence of both attractive and repulsive fifth-forces. Such small-scale features are expected to imprint possibly observable footprints on nonlinear cosmic structures, that might provide a direct way to test the scenario. In order to unveil such footprints, we have performed the first suite of high-resolution N-body simulations of McDE cosmologies, covering the coupling range $|\\beta |\\leq 1$. We find that for coupling values corresponding to fifth-forces weaker than standard gravity, the impact on structure formation is very mild, thereby showing a new type of screening mechanism for long-range scalar interactions. On the contrary, for fifth-forces comparable to or stronger than standard gravity a n...

  11. Enlarged Transformation Group: Star Models,Dark Matter Halos and Solar System Dynamics

    E-Print Network [OSTI]

    Edward Lee Green

    2014-07-25

    Previously a theory has been presented which extends the geometrical structure of a real four-dimensional space-time via a field of orthonormal tetrads with an enlarged transformation group. This new transformation group, called the conservation group, contains the group of diffeomorphisms as a proper subgroup and we hypothesize that it is the foundational group for quantum geometry. The fundamental geometric object of the new geometry is the curvature vector, C^\\mu . Using the scalar Lagrangian density C^\\mu C_\\mu \\sqrt{-g}, field equations for the free field have been obtained which are invariant under the conservation group. In this paper, this theory is further extended by development of a suitable Lagrangian for a field with sources. Spherically symmetric solutions for both the free field and the field with sources are given. A stellar model and an external, free-field model are developed. The theory implies that the external stress-energy tensor has non-compact support and hence may give the geometrical foundation for dark matter. The resulting models are compared to the internal and external Schwarzschild models. The theory may explain the Pioneer anomaly and the corona heating problem.

  12. Near-barrier Fusion and Transfer/Breakup induced by Weakly Bound and Exotic Halo Nuclei

    E-Print Network [OSTI]

    C. Beck

    2007-01-29

    This submission has been withdrawn by arXiv administrators because it is a duplicate of nucl-th/0610004.

  13. THE STELLAR HALOS OF MASSIVE ELLIPTICAL GALAXIES. II. DETAILED ABUNDANCE RATIOS AT LARGE RADIUS

    SciTech Connect (OSTI)

    Greene, Jenny E.; Murphy, Jeremy D.; Graves, Genevieve J.; Gunn, James E.; Raskutti, Sudhir; Comerford, Julia M.; Gebhardt, Karl

    2013-10-20

    We study the radial dependence in stellar populations of 33 nearby early-type galaxies with central stellar velocity dispersions ?{sub *} ?> 150 km s{sup –1}. We measure stellar population properties in composite spectra, and use ratios of these composites to highlight the largest spectral changes as a function of radius. Based on stellar population modeling, the typical star at 2R{sub e} is old (?10 Gyr), relatively metal-poor ([Fe/H] ? –0.5), and ?-enhanced ([Mg/Fe] ? 0.3). The stars were made rapidly at z ? 1.5-2 in shallow potential wells. Declining radial gradients in [C/Fe], which follow [Fe/H], also arise from rapid star formation timescales due to declining carbon yields from low-metallicity massive stars. In contrast, [N/Fe] remains high at large radius. Stars at large radius have different abundance ratio patterns from stars in the center of any present-day galaxy, but are similar to average Milky Way thick disk stars. Our observations are thus consistent with a picture in which the stellar outskirts are built up through minor mergers with disky galaxies whose star formation is truncated early (z ? 1.5-2)

  14. Contra : A Code for Adiabatic Contraction of Dark Matter Halos Oleg Y. Gnedin

    E-Print Network [OSTI]

    Gnedin, Oleg Y.

    is defined as mh(x) = (1- fb) Mh(x) Mh(1) , (4) where x r/Rvir, c Rvir/rs, and DM = 1 : Mh(x) = ln(1+cx)- cx 1+cx (5a) DM = 2 : Mh(x) = 3n,2n(cx)1/n (5b) DM = 3 : Mh(x) = (3-,cx) (5c) where n ndm, and (a

  15. The Automatic Predictability of Super Geomagnetic Storm from Halo CMEs Associated with Large Solar Flares

    E-Print Network [OSTI]

    control systems, damage of electric power grids, etc. A geomagnetic storm is initiated when the energy of the main objectives in space weather research is to predict the occurrence of geomagnetic storms based

  16. Mergers and Mass Assembly of Dark Matter Halos in a Lambda Cold Dark Matter Universe

    E-Print Network [OSTI]

    Fakhouri, Onsi Joe

    2010-01-01

    2005] provides a database for the evolution of roughly 2 ×database of the Millennium simulation [Springel et al. , 2005], which follows the evolution

  17. X-ray haloes and starformation in early-type galaxies

    E-Print Network [OSTI]

    Negri, Andrea; Ciotti, Luca

    2015-01-01

    High resolution 2D hydrodynamical simulations describing the evolution of the hot ISM in state-of-the-art axisymmetric two-component models of early-type galaxies well reproduced the observed trends of the X-ray luminosity ($L_\\mathrm{x}$) and temperature ($T_\\mathrm{x}$) with galaxy shape and rotation, however they also revealed the formation of an exceedingly massive cooled gas disc in rotating systems. In a follow-up of this study, here we investigate the effects of starformation in the disc, including the consequent injection of mass, momentum and energy in the pre-existing interstellar medium. It is found that subsequent generations of stars originate one after the other in the equatorial region; the mean age of the new stars is $> 5$ Gyr, and the adopted recipe for starformation can reproduce the empirical Kennicutt-Schmidt law. The results of the previous investigation without starformation, concerning $L_\\mathrm{x}$ and $T_\\mathrm{x}$ of the hot gas, and their trends with galactic shape and rotation, ...

  18. HST Observations of Heavy Elements in Metal-Poor Galactic Halo Stars

    E-Print Network [OSTI]

    John J. Cowan; Christopher Sneden; Timothy C. Beers; James E. Lawler; Jennifer Simmerer; James W. Truran; Francesca Primas; Jason Collier; Scott Burles

    2005-02-28

    We present new abundance determinations of neutron-capture elements Ge, Zr, Os, Ir, and Pt in a sample of 11 metal-poor (-3.1 56) elements. However, the large (and correlated) scatters of [Eu,Os,Ir,Pt/Fe] suggests that the heaviest neutron-capture r-process elements are not formed in all supernovae. In contrast, the Ge abundances of all program stars track their Fe abundances, very well. An explosive process on iron-peak nuclei (e.g., the alpha-rich freeze-out in supernovae), rather than neutron capture, appears to have been the dominant synthesis mechanism for this element at low metallicities -- Ge abundances seem completely uncorrelated with Eu.

  19. Impact of lightning on the lower ionosphere of Saturn and possible generation of halos and sprites

    E-Print Network [OSTI]

    Ebert, Ute

    -dimensional model of the electric field and electron density is used to estimate the changes of the local electron , C. Price a a Department of Geophysical, Atmospheric and Planetary Sciences, Tel-Aviv University and find that the conservative estimation of lightning charge moment change 104 to 105 C km could lead

  20. DETECTION OF A NEARBY HALO DEBRIS STREAM IN THE WISE AND 2MASS SURVEYS

    SciTech Connect (OSTI)

    Grillmair, Carl J. [Spitzer Science Center, 1200 E. California Blvd., Pasadena, CA 91125 (United States); Cutri, Roc; Masci, Frank J.; Conrow, Tim [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Sesar, Branimir [Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Eisenhardt, Peter R. M. [Jet Propulsion Laboratory, California Institute of Technology, MS 169-327, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Wright, Edward L., E-mail: carl@ipac.caltech.edu, E-mail: roc@ipac.caltech.edu, E-mail: fmasci@ipac.caltech.edu, E-mail: tim@ipac.caltech.edu, E-mail: bsesar@astro.caltech.edu, E-mail: peter.r.eisenhardt@jpl.nasa.gov, E-mail: wright@astro.ucla.edu [Department of Physics, University of California, Los Angeles, CA 90095 (United States)

    2013-06-01

    Combining the Wide-Field Infrared Survey Explorer All-Sky Release with the Two Micron All Sky Survey Point Source Catalog, we detect a nearby, moderately metal-poor stellar debris stream spanning 24° across the southern sky. The stream, which we designate Alpheus, is at an estimated distance of ?1.9 kpc. Its position, orientation, width, estimated metallicity, and, to some extent, its distance, are in approximate agreement with what one might expect of the leading tidal tail of the southern globular cluster NGC 288.

  1. The Arecibo Galaxy Environment Survey X: The Structure of Halo Gas Around M33

    E-Print Network [OSTI]

    Keenan, Olivia; Taylor, Rhys; Minchin, Robert

    2015-01-01

    As part of the HI Arecibo Galaxy Environments Survey (AGES) we have observed 5$\\times$4 degrees of sky centred on M33, reaching a limiting column density of $\\sim 1.5 \\times 10^{17}$ cm$^{-2}$ (line width of 10 km s$^{-1}$ and resolution 3.5\\arcmin). We particularly investigate the absence of optically detected dwarf galaxies around M33, something that is contrary to galaxy formation models. We identify 22 discrete HI clouds, 11 of which are new detections. The number of objects detected and their internal velocity dispersion distribution is consistent with expectations from standard galaxy formation models. However, the issue remains open as to whether the observed velocity dispersions can be used as a measure of the HI clouds total mass i.e. are the velocities indicative of virialised structures or have they been influenced by tidal interactions with other structures in the Local Group? We identify one particularly interesting HI cloud, AGESM33-31, that has many of the characteristics of HI distributed in t...

  2. Beryllium in Disk and Halo Stars -- Evidence for a Beryllium Dispersion in Old Stars

    E-Print Network [OSTI]

    Ann Merchant Boesgaard; Megan C. Novicki

    2005-12-13

    The study of Be in stars of differing metal content can elucidate the formation mechanisms and the Galactic chemical evolution of Be. We have obtained high-resolution, high signal-to-noise spectra of the resonance lines of Be II in eight stars with the high-dispersion spectrograph (HDS) on the Subaru 8.2 m telescope on Mauna Kea. Abundances of Be have been determined through spectrum synthesis. The stars with [Fe/H] values > -1.1 conform to the published general trend of Be vs Fe. We have confirmed the high Be abundance in HD 94028 and have found a similarly high Be abundance in another star, HD 132475, at the same metallicity: [Fe/H] = -1.5. These two stars are 0.5 - 0.6 dex higher in Be than the Be-Fe trend. While that general trend contains the evidence for a Galaxy-wide enrichment in Be and Fe, the higher Be abundances in those two stars indicates local Be enrichments. Possible enrichment mechanisms include hypernovae and multiple supernova explosions contained in a superbubble. The star G 64-37 has [Fe/] = -3.2; we have determined its Be abundance to look for evidence of a Be plateau. It's Be abundance appears to extend the Be-Fe trend to lower Fe abundances without any evidence for a plateau as had been indicated by a high Be abundance in another very metal-poor star, G 64-12. Although these two stars have similar Be abundances within the errors, it could be that their different Be values may be indicating that a Be dispersion exists even at the lowest metallicities.

  3. Mergers and Mass Assembly of Dark Matter Halos in a Lambda Cold Dark Matter Universe

    E-Print Network [OSTI]

    Fakhouri, Onsi Joe

    2010-01-01

    of a ? cold dark matter universe. MNRAS, 376:215–232, Marchlarge-scale structure in a universe dominated by cold darkfirst structures in the early Universe. Nature, 433:389–391,

  4. Evidence of a halo formation mechanism in the Spallation Neutron Source

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield MunicipalTechnical Report:Speeding accessby aLED Street Lighting HostDISCLAIMERlinac (Journal Article)

  5. A hybrid fast-multipole technique for space-charge tracking with halos

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield MunicipalTechnicalInformation4563 LLNL(Technical Report)Asegment, largedensity

  6. Mergers and Mass Accretion for Infalling Halos Both End Well Outside

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing(JournalspectroscopyReport) | SciTechelement methodbyoxide embedded in

  7. Mergers and Mass Accretion for Infalling Halos Both End Well Outside

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing(JournalspectroscopyReport) | SciTechelement methodbyoxide embedded inCluster Virial

  8. Evidence of a halo formation mechanism in the Spallation Neutron Source

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing(Journal Article) | SciTech(Journal(Patent)pressure in BaSwitching. (Journal Article)

  9. Primordial non-Gaussianity in the Bispectrum of the Halo Density Field

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTech ConnectSpeeding accessusers'(x≤2) surface:SciTechinvestigation

  10. Primordial non-Gaussianity in the Bispectrum of the Halo Density Field

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTech ConnectSpeeding accessusers'(x≤2) surface:SciTechinvestigation(Journal Article) |

  11. Summary of the 2014 Beam-Halo Monitoring Workshop (Conference) | SciTech

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail. (Conference)Feedback System inStatus ofSmall

  12. Summary of the 2014 Beam-Halo Monitoring Workshop (Conference) | SciTech

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail. (Conference)Feedback System inStatus ofSmallConnect Conference: Summary of the

  13. Unbound Particles in Dark Matter Halos (Journal Article) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.Theory of rare Kaon and(Conference) |Article)(Technical Report) |energetic 263

  14. Unbound Particles in Dark Matter Halos (Journal Article) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.Theory of rare Kaon and(Conference) |Article)(Technical Report) |energetic 263Unbound

  15. Evidence of a halo formation mechanism in the Spallation Neutron Source

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

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

  16. Microwave lamp with multi-purpose rotary motor

    DOE Patents [OSTI]

    Ury, M.G.; Turner, B.; Wooten, R.D.

    1999-02-02

    In a microwave powered electrodeless lamp, a single rotary motor is used to (a) rotate the bulb and (b) provide rotary motion to a blower or pump means for providing cooling fluid to the magnetron and/or to a forced gas cooler for providing cooling gas to the bulb. The blower may consist of only of an impeller without the usual blower housing. The motor, bulb stem and bulb, or motor, bulb stem, bulb and blower may be formed as an integral unit so as to facilitate replacement. 8 figs.

  17. Microwave lamp with multi-purpose rotary motor

    DOE Patents [OSTI]

    Ury, Michael G. (Bethesda, MD); Turner, Brian (Myersville, MD); Wooten, Robert D. (Rockville, MD)

    1999-01-01

    In a microwave powered electrodeless lamp, a single rotary motor is used to a) rotate the bulb and b) provide rotary motion to a blower or pump means for providing cooling fluid to the magnetron and/or to a forced gas cooling for providing cooler gas to the bulb. The blower may consist of only of an impeller without the usual blower housing. The motor, bulb stem and bulb, or motor, bulb stem, bulb and blower may be formed as an integral unit so as to facilitate replacement.

  18. Lighting a building with a single bulb : toward a system for illumination in the 21st c.; or, A centralized illumination system for the efficient decoupling and recovery of lighting related heat

    E-Print Network [OSTI]

    Levens, Kurt Antony, 1961-

    1997-01-01

    Piping light represents the first tenable method for recovery and reutilization of lighting related heat. It can do this by preserving the energy generated at the lamp as radiative, departing from precedent and avoiding ...

  19. Westinghouse and Fuzhou Permitted to Restart Distribution of...

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

    and Fuzhou Permitted to Restart Distribution of Light Bulb Products Westinghouse and Fuzhou Permitted to Restart Distribution of Light Bulb Products August 6, 2010 - 4:26pm Addthis...

  20. Energy-Department Supported Scientist Receives Nobel Prize for...

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

    red and green diodes, blue diodes made the white light coming from today's LED light bulbs possible. LED light bulbs are as much as 85% more energy efficient and last up to 25...