DOCSLIB.ORG

General Disclaimer One Or More of the Following Statements May Affect

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
General Disclaimer One Or More of the Following Statements May Affect General Disclaimer One or more of the Following Statements may affect this Document This document has been reproduced from the best copy furnished by the organizational source. It is being released in the interest of making available as much information as possible. This document may contain data, which exceeds the sheet parameters. It was furnished in this condition by the organizational source and is the best copy available. This document may contain tone-on-tone or color graphs, charts and/or pictures, which have been reproduced in black and white. This document is paginated as submitted by the original source. Portions of this document are not fully legible due to the historical nature of some of the material. However, it is the best reproduction available from the original submission. Produced by the NASA Center for Aerospace Information (CASI) I t (NASA-Td-851U3) 'ILLIPthATULL 11d; ELZAEb':AL N84 -3!234 ALUbDAMCP. S IN Tbtr ABILL C I L altb A t) 16 DBhlVEv FbU4 X-tAY UbS.: LVAIILN . ) (NASA) 33 N UC AU3/tik A01 CSCL OJb UticI dk G'/90 23130 N/SA Technical Memorandum 85103 TEMPERATURE AND ELEMENTAL ABUNDANCES IN THE ABELL CLUSTER A 576 DERIVED FROM X-RAY OBSERVATIONS .t R. Rothenflug L. Vigroux R. F. Mttshotzky S. S. Holt Oct r I ;I ,.T p:•, ^1 VEp t SEPTEMBER 1983 National Aeronautics and Space Administration 4 Goddard Space Fligil Center Gi eenbelt Maryland 20771 lift? <^$^^ U^r ., 2^^--^ ^ --- ^ qtr t . e ^7 C a Submitted to The Astrophysical Journal t 0, J 4a i e TEMPERATURE AND ELEMENTAL. ABUNDANCES IN THE AEELL BLUSTER A 576 DERIVED FROM i X-RAY OBSEPVATIONS . R.Rothenflug, L.Vigroux Service d'Astrophysique 1 t C.E.N. Saclay , 91191 Gif-sur-Yvette Cedex France and R.F.Mushotzky, S.S.Holt Laboratory for High Energy Astrophysics NASA/Goddard Space Flight Center Greenbelt, Maryland 20771 USA Received 1982, February 23 / f 4 Running title; X-Ray Spectrum of A 576 4 p.. 1' t do -0. o. 1 or X X - 2 - ORIGINAL F;' . OF POOR Q 9 i ABSTRACT We report results of Einstein Solid State Spe g trometer obser- vations of the central region of Abell 576 combined with HIM-1 spectra of the total cluster. We detected line emission due to r e Fe, Si and S from a hat (< 2.4 10 7 °K) plasma in the central region. i The temperature of the total cluster spectrum (4+11.4 10 7K) may be in conflict with the central temperature. This difference can be 3D explained either if cooling takes place in the center, or if part {{i of the measured emission is due to individual galaxies. If the 1 X-ray emission comes from the intergalactic gas only, there is some difficulty in producing all the silicon observed in the galaxies of - i A 576. ,. a 4 F Jt 1 I Subject headings: Abundances - Galaxies: clusters of - X-rays: sources X-rays: spectra t S ► V J 3 OF POW( 4j { /f I. INTRODUCTION Recant theosl*o5ti.cal work (Saraxin and Bahcall 1978; Smith, Mushotzky and Serlemitsos - S.M.S.-,3979) has stressed the importance of X-ray spectra in interpreting; the physical condition, in X-ray clusters of galaxies. In addition recent imaging results from the Einstein Observatory (White and Silk 1980 (hereafter refered to as W.S.); Branduardi-Raymont et al.1981) have pointed out the need for high quality X-ray spectra in order to unfold the X-ray spatial results. Furthermore it is only through high quality X-ray spectral measurements that the chemical abundances of the heavy elements can be determined for the intergalactic gas in clusters. The abundance of heavy elements in the intergalactic gas can place strong; constraint on galactic and cluster evolutionnary models. In the classical picture, the heavy elements have been expelled from the galaxy either by a i 5 hot wind driven by supernovae explosion (Larson 1974) or by stripping; of the interstellar gas by the ram pressure due to the motion of the galaxies in the cluster (Gunn, Gott, 1972). At later stages evaporation could be r important in removing gas. However, most of the observations have been done so far on untypical high X-ray luminosity clusters, which generally are • dynamically evolved.On the contrary we wanted to observe a typical X-ray cluster populated with normal galaxies. The cluster A 576 was selected on the basis of its galaxy content and X-ray flux which look like a "typical" Abell cluster. r^ f^ 4 - ORIGINAL r, A 0 OF POOR QUALI VV In this paper we report results of Einstein Solid State Spectrometer (SSS) observations of the central region of Abell 576 combined with HSAC-1 spectra of t4c total cluster. These results indicate, as do the imaging data of W.S. that the X-ray gas in A 576 cannot obey a D = 5/3 polytropic equation of state. We shall, tentatively, interpret this either as evi- dente for a cooling, flow in the core of A 576 similar to that in the Perseus cluster (Fabian, Nulsen, 1977; Mushotzky et al. 1981) or due to the presence of soft X-rays associa.ed with individual galaxies in the center of the cluster. We also present data on the elemental abundances in A 576 and find that Fe, S and Si have roughly half solar abundance, consistent with the Fe results for many other clusters (Mushotzky 1975). Conse- quences of this measurement for galactic evolution are presented in the last section. 11. DATA ANALYSIS AND INSTRUMENT DESCRIPTION i ^ s r The SSS consists of a cryogenically cooled Si(Li) detector at the a focus of the Einstein Observatory X-ray telescope. It has a 3' radius circular beam with roughly uniform response across the field. The detector and telescope combination is sensitive in the 0.5 - 4.5 keV band with N 160 eV FWHM energy resolution approximately independent of energy. A more complete description of the instrumentation may be found in Holt et al. (1979). The SSS observatioi:s of the central region of A 576 were obtained in a ^,, 15,000 second exposure in September 1979 resulting, in .v 4000 source counts. Of this total number, the contribution of the 8th mag K star in the field of view is estimated to be far less than 10% (Vaiana et al. 1981). ORIG INAL PA,,^^`Z y OF P4OR QUALI The SSS spectra have been fit to the model of an isothermal Ras i.: collisional equilibrium. Two models of such a gas have been used, one, that jt is due to Raymond and Smith, R-S, (1977) has been described in detail before (Holt, 1979). The other model referred to as X-R (Rothenflua, Arnaud, 1983) was developed at Saclay, mainly based on the compilation of atomic data listed in Kato (1976). The main difference between these two models lies in the ionization balance. The R-S model is based primarily on .- ionization cross sections of Summers (1974) while the K-R model is based on the cross sections of Lotz (1967) (see appendix and also Schnopper et al., 1982). The net result is that the maximum of equilibrium abundance is shifted to higher temperatures for the R-S model in comparison with the K-12 model. This shift is most noticeable for the least ionized species (e.g. Fe XVII or re XVIII). For helium like and hydrogen like ions the differences are small. The HERO-1 experiment A-2 a instrumentation has been described in detail by Rothschild et al. (1978). Previous HEAO-1 observations of A 576 have been reported by Pravdo et al. (1580) who used a summed rate combina- tion, R15, in their analysis. In this paper we have used the results of ,.. 4 a long; pointing at A 576 which occurred on day 297 of 1978. c t This exposure of 8600 seconds resulted in,- 6500 source counts in the 2 - 20 keV band. The major origin of uncertainty in the data is not due to photon counting; statistics or uncertainty in the internal backfround, but is due; to ,intrinsic fluctuations in the diffuse X-ray background. i a. The A-2-experiment on HFAO-1 was a collaborative effort led by E.Boldt of GSFC and G.Garmire of CIT, W th collaborators at GSFC, CIT, JPL, and UCB. s - g - ORIGINAL PAOM-. ;1- OF POOH QUAi,1V Mo RESULTS . The SSS spectrum was well fit by either the R-S or K-R model with a A reduction in 2 of 1H compared to a simple thermal breamsstrahlung fit (Figure 1). For the addition of A additional parameters, the reduction T2 in is significant at greater than the 90% confidence level. The best f1t temperature is 1.6 keV (:;3) (90% confidence errors) with roughly half solar abundances of Fe, Si and S (see Table 1 and Figure 2). As seen in Table 1, there is no significant difference found for the temperature or the abundance determinations between the R-S and K-R models. The best fit absorption of 1.1 x 1021 at/rm2 is consistent with the G x 10`0 at/cm2 derived from 21 cm data (Neiles, 1975). The best fait emission integral, ne 2V, is 6,6 x 1066 .h 5o cm . rt The HEAO-1 experiment A-2 data with a larger angular resolution of 3 0 x 1.5 0 were fit to a simple thermal model (Figure 3). The best fit . temperature was K= 3.5 +3- 1 : 02, keV (90% confidence).
Load more

Recommended publications
  • JOHN R. THORSTENSEN Address
    CURRICULUM VITAE: JOHN R. THORSTENSEN Address: Department of Physics and Astronomy Dartmouth College 6127 Wilder Laboratory Hanover, NH 03755-3528; (603)-646-2869 [email protected] Undergraduate Studies: Haverford College, B. A. 1974 Astronomy and Physics double major, High Honors in both. Graduate Studies: Ph. D., 1980, University of California, Berkeley Astronomy Department Dissertation : \Optical Studies of Faint Blue X-ray Stars" Graduate Advisor: Professor C. Stuart Bowyer Employment History: Department of Physics and Astronomy, Dartmouth College: { Professor, July 1991 { present { Associate Professor, July 1986 { July 1991 { Assistant Professor, September 1980 { June 1986 Research Assistant, Space Sciences Lab., U.C. Berkeley, 1975 { 1980. Summer Student, National Radio Astronomy Observatory, 1974. Summer Student, Bartol Research Foundation, 1973. Consultant, IBM Corporation, 1973. (STARMAP program). Honors and Awards: Phi Beta Kappa, 1974. National Science Foundation Graduate Fellow, 1974 { 1977. Dorothea Klumpke Roberts Award of the Berkeley Astronomy Dept., 1978. Professional Societies: American Astronomical Society Astronomical Society of the Pacific International Astronomical Union Lifetime Publication List * \Can Collapsed Stars Close the Universe?" Thorstensen, J. R., and Partridge, R. B. 1975, Ap. J., 200, 527. \Optical Identification of Nova Scuti 1975." Raff, M. I., and Thorstensen, J. 1975, P. A. S. P., 87, 593. \Photometry of Slow X-ray Pulsars II: The 13.9 Minute Period of X Persei." Margon, B., Thorstensen, J., Bowyer, S., Mason, K. O., White, N. E., Sanford, P. W., Parkes, G., Stone, R. P. S., and Bailey, J. 1977, Ap. J., 218, 504. \A Spectrophotometric Survey of the A 0535+26 Field." Margon, B., Thorstensen, J., Nelson, J., Chanan, G., and Bowyer, S.
    [Show full text]
  • From Messier to Abell: 200 Years of Science with Galaxy Clusters
    Constructing the Universe with Clusters of Galaxies, IAP 2000 meeting, Paris (France) July 2000 Florence Durret & Daniel Gerbal eds. FROM MESSIER TO ABELL: 200 YEARS OF SCIENCE WITH GALAXY CLUSTERS Andrea BIVIANO Osservatorio Astronomico di Trieste via G.B. Tiepolo 11 – I-34131 Trieste, Italy [email protected] 1 Introduction The history of the scientific investigation of galaxy clusters starts with the XVIII century, when Charles Messier and F. Wilhelm Herschel independently produced the first catalogues of nebulæ, and noticed remarkable concentrations of nebulæ on the sky. Many astronomers of the XIX and early XX century investigated the distribution of nebulæ in order to understand their relation to the local “sidereal system”, the Milky Way. The question they were trying to answer was whether or not the nebulæ are external to our own galaxy. The answer came at the beginning of the XX century, mainly through the works of V.M. Slipher and E. Hubble (see, e.g., Smith424). The extragalactic nature of nebulæ being established, astronomers started to consider clus- ters of galaxies as physical systems. The issue of how clusters form attracted the attention of K. Lundmark287 as early as in 1927. Six years later, F. Zwicky512 first estimated the mass of a galaxy cluster, thus establishing the need for dark matter. The role of clusters as laboratories for studying the evolution of galaxies was also soon realized (notably with the collisional stripping theory of Spitzer & Baade430). In the 50’s the investigation of galaxy clusters started to cover all aspects, from the distri- bution and properties of galaxies in clusters, to the existence of sub- and super-clustering, from the origin and evolution of clusters, to their dynamical status, and the nature of dark matter (or “positive energy”, see e.g., Ambartsumian29).
    [Show full text]
  • Arxiv:Astro-Ph/0007126V1 11 Jul 2000
    The Infall Region of Abell 576: Independent Mass and Light Profiles Kenneth Rines and Margaret J. Geller Harvard-Smithsonian Center for Astrophysics, 60 Garden St, Cambridge, MA 02138 krines, [email protected] Antonaldo Diaferio Universit`adegli Studi di Torino, Dipartimento di Fisica Generale “Amedeo Avogadro”, Torino, Italy Joseph J. Mohr1 Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 Gary A. Wegner Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 ABSTRACT We describe observations of the nearby (cz = 11, 487 km s−1) cluster of galaxies Abell 576 beyond the virial radius and into the infall region where galaxies are on their first or second pass through the cluster. Using 1057 redshifts, we use the infall pattern in redshift space to determine the mass profile of A576 to a radius of ∼ 4 h−1Mpc. This mass estimation technique makes no assumptions about the equilibrium state of the cluster. Within ∼ 1 h−1Mpc, the mass profile we derive exceeds that determined from X-ray observations by arXiv:astro-ph/0007126v1 11 Jul 2000 a factor of ∼ 2.5. At ∼ 2.5 h−1Mpc, however, the mass profile agrees with virial mass estimates. Our mass profile is consistent with a Navarro, Frenk, & White (1997) or Hernquist (1990) profile, but it is inconsistent with an isothermal sphere. R-band images of a 3◦ × 3◦ region centered on the cluster allow an independent determination of the cluster light profile. We calculate the integrated mass-to-light ratio as a function of cluster radius; it decreases −1 smoothly from the core to M/LR ∼ 300h at ∼ 4 h Mpc.
    [Show full text]
  • Effects of Rotation Arund the Axis on the Stars, Galaxy and Rotation of Universe* Weitter Duckss1
    Effects of Rotation Arund the Axis on the Stars, Galaxy and Rotation of Universe* Weitter Duckss1 1Independent Researcher, Zadar, Croatia *Project: https://www.svemir-ipaksevrti.com/Universe-and-rotation.html; (https://www.svemir-ipaksevrti.com/) Abstract: The article analyzes the blueshift of the objects, through realized measurements of galaxies, mergers and collisions of galaxies and clusters of galaxies and measurements of different galactic speeds, where the closer galaxies move faster than the significantly more distant ones. The clusters of galaxies are analyzed through their non-zero value rotations and gravitational connection of objects inside a cluster, supercluster or a group of galaxies. The constant growth of objects and systems is visible through the constant influx of space material to Earth and other objects inside our system, through percussive craters, scattered around the system, collisions and mergers of objects, galaxies and clusters of galaxies. Atom and its formation, joining into pairs, growth and disintegration are analyzed through atoms of the same values of structure, different aggregate states and contiguous atoms of different aggregate states. The disintegration of complex atoms is followed with the temperature increase above the boiling point of atoms and compounds. The effects of rotation around an axis are analyzed from the small objects through stars, galaxies, superclusters and to the rotation of Universe. The objects' speeds of rotation and their effects are analyzed through the formation and appearance of a system (the formation of orbits, the asteroid belt, gas disk, the appearance of galaxies), its influence on temperature, surface gravity, the force of a magnetic field, the size of a radius.
    [Show full text]
  • Alma Mater Studiorum Universit`A Degli Studi Di Bologna
    Alma Mater Studiorum Universit`adegli Studi di Bologna Facolt`adi Scienze Matematiche, Fisiche e Naturali Dipartimento di Astronomia DOTTORATO DI RICERCA IN ASTRONOMIA Ciclo XXII ANALYSIS OF THE NUCLEAR PROPERTIES OF BRIGHTEST CLUSTER GALAXIES AND COMPARISON WITH “NORMAL” RADIO GALAXIES. Dottoranda: ELISABETTA LIUZZO Coordinatore: Relatore: Chiar.mo Prof. Chiar.mo Prof. LAURO MOSCARDINI GABRIELE GIOVANNINI Co-relatore: Dr. MARCELLO GIROLETTI Settore Scientifico Disciplinare: Area 02 - Scienze Fisiche FIS/05 Astronomia e Astrofisica Esame Finale Anno 2010 QUESTA TESI E’ STATA SVOLTA NELL’AMBITO DELLE ATTIVITA’ DI RICERCA DELL’ ISTITUTO DI RADIOASTRONOMIA DELL’ ISTITUTO NAZIONALE DI ASTROFISICA (BOLOGNA) Contents Abstract i 1 General properties of BCGs 1 1.1 Observational properties. 1 1.1.1 Morphological types. 1 1.1.2 Position in the cluster. 5 1.1.3 Radii and Surface brightness. 5 1.1.4 Size-luminosity relation. 7 1.1.5 Ellipticity. 9 1.1.6 Dynamical mass. 9 1.1.7 The Fundamental Plane. 10 1.1.8 Faber−Jackson relation. 12 1.1.9 Stellar populations. 14 1.1.10 Emission line properties. 16 1.2 Theories on the origin of BCGs. 20 1.2.1 Cooling Flow. 20 1.2.2 Galactic cannibalism. 22 1.2.3 Galaxy merging. 23 1.3 Radio loud BCGs. 28 1.3.1 The cooling flow problem. 31 2 Pc scale properties of BCGs 37 2.1 The definition of a complete sample of BCGs. 37 2.2 The data set. 40 2.2.1 The data reduction. 40 2.3 Notes on Individual Sources. 42 i ii CONTENTS 2.3.1 NGC708 (B2 0149+35) in Abell 262.
    [Show full text]
  • Arxiv:Astro-Ph/9808050 V1 6 Aug 1998 Rssfo H Cteigo Lcrn Ncutr Fgalax of Clusters in Electrons of Suny Scattering the the Con Occur
    To appear in Physics Reports THE SUNYAEV-ZEL’DOVICH EFFECT Mark Birkinshaw1 Department of Physics, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, UK ABSTRACT The Sunyaev-Zel’dovich effect causes a change in the apparent brightness of the Cosmic Microwave Background Radiation towards a cluster of galaxies or any other reservoir of hot plasma. Measurements of the effect provide distinctly different information about cluster properties than X-ray imaging data, while combining X-ray and Sunyaev-Zel’dovich effect data leads to new insights into the structures of cluster atmospheres. The effect is redshift-independent, and so provides a unique probe of the structure of the Universe on the largest scales. The present review discusses the theory of the Sunyaev-Zel’dovich effect and collects published results for many clusters, presents the overall conclusions that may be drawn from the detections so far, and discusses the prospects for future research on the Sunyaev-Zel’dovich effects. Subject headings: Sunyaev-Zel’dovich Effect; Clusters; Microwave Background Radiation arXiv:astro-ph/9808050 v1 6 Aug 1998 1. Astrophysical Context Compton scattering is one of the major physical processes that couples matter and radiation. Its importance is often stressed in highly relativistic environments where large energy transfers occur: for example, in the synchrotron self-Compton process that may be responsible for much of the X-radiation from active galactic nuclei (e.g., Fabian et al. 1986). However, the Compton process also has observable consequences in low-energy environments, where small energy transfers occur. The Sunyaev-Zel’dovich effect, which arises from the scattering of electrons in clusters of galaxies on the cosmic microwave 1Also Smithsonian Institution Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138, USA –2– background radiation field, is perhaps the most important astrophysical example.
    [Show full text]
  • Dark Matter in Galaxy Clusters: Shape, Projection, and Environment
    Dark Matter in Galaxy Clusters: Shape, Projection, and Environment A Thesis Submitted to the Faculty of Drexel University by Austen M. Groener in partial fulfillment of the requirements for the degree of Doctor of Philosophy September 2015 c Copyright 2015 Austen M. Groener. ii Dedications I dedicate this thesis to my family, and to my wife, who supported me unconditionally throughout my career as a scientist. iii Acknowledgments I have many people to thank for making this work a possibility. Firstly, I would like to thank my advisor, Dr. David Goldberg. His guidance, support, and most of all his patience provided the framework for which I was able to build my work from. I would also like to thank my dissertation committee members, Dr. Michael Vogeley, Dr. Gordon Richards, Dr. Luis Cruz, and Dr. Andrew Hicks, for their constructive criticism and support of my research. I would also like to acknowledge fellow graduate students for their assistance and support. A special thanks to Justin Bird, Markus Rexroth, Frank Jones, Crystal Moorman, and Vishal Kasliwal for allowing me to bounce ideas off of them, which was a truly important but time consuming process. iv Table of Contents List of Tables ........................................... vi List of Figures .......................................... vii Abstract .............................................. ix 1. Introduction .......................................... 1 1.1 The Radial Density Profile.................................. 2 1.2 Cluster Scaling Relations .................................. 5 1.3 Clusters and Environment.................................. 7 1.4 Outline ............................................ 11 2. Cluster Shape and Orientation .............................. 12 2.1 Introduction.......................................... 12 2.2 Triaxial Projections...................................... 14 2.3 Sample and Methods..................................... 15 2.3.1 Simulation Sample .................................... 15 2.3.2 Methods.........................................
    [Show full text]
  • The Infall Region of Abell 576: Independent Mass and Light Profiles
    Dartmouth College Dartmouth Digital Commons Open Dartmouth: Published works by Dartmouth faculty Faculty Work 11-2000 The Infall Region of Abell 576: Independent Mass and Light Profiles Kenneth Rines Harvard-Smithsonian Center for Astrophysics Margaret J. Geller Harvard-Smithsonian Center for Astrophysics Antonaldo Diaferio University of Turin Joseph J. Mohr University of Chicago Gary A. Wegner Dartmouth College Follow this and additional works at: https://digitalcommons.dartmouth.edu/facoa Part of the External Galaxies Commons, and the Physical Processes Commons Dartmouth Digital Commons Citation Rines, Kenneth; Geller, Margaret J.; Diaferio, Antonaldo; Mohr, Joseph J.; and Wegner, Gary A., "The Infall Region of Abell 576: Independent Mass and Light Profiles" (2000). Open Dartmouth: Published works by Dartmouth faculty. 2228. https://digitalcommons.dartmouth.edu/facoa/2228 This Article is brought to you for free and open access by the Faculty Work at Dartmouth Digital Commons. It has been accepted for inclusion in Open Dartmouth: Published works by Dartmouth faculty by an authorized administrator of Dartmouth Digital Commons. For more information, please contact [email protected]. THE ASTRONOMICAL JOURNAL, 120:2338È2354, 2000 November ( 2000. The American Astronomical Society. All rights reserved. Printed in U.S.A. THE INFALL REGION OF ABELL 576: INDEPENDENT MASS AND LIGHT PROFILES KENNETH RINES AND MARGARET J. GELLER Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138; krines=cfa.harvard.edu, mgeller=cfa.harvard.edu ANTONALDO DIAFERIO Universita` degli Studi di Torino, Dipartimento di Fisica Generale Amedeo Avogadro, Torino, Italy JOSEPH J. MOHR1 Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 AND GARY A.
    [Show full text]
  • NOAO Annual Report FY 2001 October 1, 2000 Œ September 30
    Cerro Tololo Inter-American Observatory Kitt Peak National Observatory US Gemini Program NATIONAL OPTICAL ASTRONOMY OBSERVATORY NOAO Annual Report FY 2001 October 1, 2000 – September 30, 2001 NOAO is operated by the Association of Universities for Research in Astronomy under cooperative agreement with the National Science Foundation NOAO ANNUAL REPORT FY 2001 TABLE OF CONTENTS 1. INTRODUCTION ..................................................................................................................................1 2. SCIENTIFIC RESEARCH ...................................................................................................................2 2.1 Cerro Tololo Inter-American Observatory (CTIO) .........................................................................2 2.1.1 Galaxy Cluster Found Using Gravitational Distortion..........................................................2 2.1.2 High Spatial Density of Halo White Dwarfs .........................................................................2 2.2 Kitt Peak National Observatory (KPNO).........................................................................................3 2.2.1 The Fossil History of Chemical Enrichment in the Early Galaxy ........................................3 2.2.2 The Challenge of Investigating Large-Scale Flows in the Universe ....................................4 2.3 Science from the Gemini Telescopes ..............................................................................................5 3. USER SUPPORT AND TELESCOPE IMPROVEMENTS
    [Show full text]
  • Program Plan 1976 8~0~ National Radio Astronomy Observatory
    U'!; A r( / 0~~ o - Oosaws NATIONAL RADIO 0~ ASTRONOMY o r~ OBSERVATORY PROGRAM PLAN 1976 8~0~ NATIONAL RADIO ASTRONOMY OBSERVATORY CALENDAR YEAR 1976 PROGRAM PLAN NATIONAL RADIO ASTRONOMY OBSERVATORY CALENDAR YEAR 1976 PROGRAM PLAN I 1 Table of Contents Section-Pg I. Introduction.... ...... ....... ...... ...... ... 1 II. Scientific Program................ ....... 2 III. Rsearch Instruments . .......... ........ ........... A. RA Scientific Staff Programs.. ....... .. .... 13 IV. Equipment. ........ .... ..... .. .. .. 7 Committees.. .NR :.4.6 :.. 0 00. B. NRA Permanent ScientifiablCStaff with Major V. Operations andMaintenance............. .......... 8 VI. Construction..Sc ien.tific ..Inte.rests.... .... ... ....... ... ................... ............ 1 11 VII. Financial Plann.......... ........ ..... 12 Appendix C. NRAOrgani zational Chart.... ........ ... ....... 20 21 ........................ D. NRA ommittees.............. NATIONAL RADIO ASTRONOMY OBSERVATORY CALENDAR YEAR 1976 PROGRAM PLAN I. INTRODUCTION The National Radio Astronomy Observatory is operated by Associated Universities, Inc., under contract to the National Science Foundation, and serves as one of the Foundation's National Centers for research in radio . : astronomy. .At least 60 percent of the observing time On the four major: i..... " .j;=~;-a?;z-., ~.~ ';- radio telescopes which the Observatory operates wi-1l .be used by visiting . T scientists both from universities .and institutions elsewhere in the United States and from abroad.' The research planned for. this period by the NRAO permanent staff and the visiting investigators is summarized in the follow- ing section. The: telescope systems--the 36-foot millimeter wavelength telescope, the 140-foot telescope, the 300-foot meridian transit telescope, and the four-element variable baseline interferometer--are all heavily subscribed and an important aspect of the Observatory's operation is the design and development of new research instrumentation for these telescope systems.
    [Show full text]
  • A Catalog of Galaxy Clusters Observed by XMM-Newton
    A&A 478, 615–658 (2008) Astronomy DOI: 10.1051/0004-6361:20077930 & c ESO 2008 Astrophysics A catalog of galaxy clusters observed by XMM-Newton S. L. Snowden1, R. F. Mushotzky2,K.D.Kuntz3, and D. S. Davis4,5 1 Code 662, NASA/Goddard Space Flight Center, Greenbelt, MD 20771, USA e-mail: [email protected] 2 Code 662, NASA/Goddard Space Flight Center, Greenbelt, MD 20771, USA e-mail: [email protected] 3 Henry A. Rowland Department of Physics and Astronomy, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA e-mail: [email protected] 4 Department of Physics, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA 5 CRESST and the Astroparticle Physics Laboratory, NASA/GSFC, Greenbelt, MD 20771, USA e-mail: [email protected] Received 22 May 2007 / Accepted 3 October 2007 ABSTRACT Aims. We present a uniform catalog of the images and radial profiles of the temperature, abundance, and brightness for 70 clusters of galaxies observed by XMM-Newton. Methods. We use a new “first principles” approach to the modeling and removal of the background components; the quiescent particle background, the cosmic diffuse emission, the soft proton contamination, and the solar wind charge exchange emission. Each of the background components demonstrate significant spectral variability, several have spatial distributions that are not described by the photon vignetting function, and all except for the cosmic diffuse emission are temporally variable. Because these backgrounds strongly affect the analysis of low surface brightness objects, we provide a detailed description our methods of identification, characterization, and removal.
    [Show full text]
  • Biblography (PDF)
    Papers In Refereed Journals Joel N. Bregman 1. The Blue Stars Above the Turn-Off in M67: Horizontal Branch or Blue Stragglers?; Strom, S. E., Strom, K. M., and Bregman, J. N. 1971, Pub. A.S.P., 83, 768. 2. Circumstellar Shells in the Young Cluster NGC 2264. II. Infrared and Further Optical Observations, S. E. Strom, K. M. Strom, A. L. Brooke, J. N. Bregman, and J. Yost, Ap. J., 171, 267, 1972. 3. Period-Luminosity-Color Relationship and Pulsation Modes of Pulsating Variable Stars, M. Breger and J. N. Bregman, Ap. J., 200, 343, 1975. 4. The Violet Opacity of Carbon Stars, J. D. Bregman and J. N. Bregman, Ap. J., 222, L41, 1978. 5. Radiative Accretion Flow onto Giant Galaxies in Clusters, W. G. Mathews and J. N. Bregman, Ap. J., 224, 308, 1978. 6. Galactic Winds and the Hubble Sequence, J. N. Bregman, Ap. J., 224, 768, 1978. 7. Galactic Wakes and the Magellanic Stream, J. N. Bregman, Ap. J., 229, 514, 1979. 8. The Galactic Fountain of High Velocity Clouds, J. N. Bregman, Ap. J., 236, 577, 1980. 9. A Wind in the Galaxy, J. N. Bregman, Ap. J., 237, 280, 1980. 10. X-Ray Coronae Around Galaxies, J. N. Bregman, Ap. J., 237, 681, 1980. 11. Detection of Lyman Continuum Absorption in the BL Lac Object 0735+178, J. N. Bregman, A. E. Glassgold, and P. J. Huggins, Ap. J., 249, 13, 1980. 12. Multifrequency Observations of the Red QSO 1413+135, J. N. Bregman, M. J.Lebofsky, M. F. Aller, G. H. Rieke, H.
    [Show full text]