Astrophysics in 2006
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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. -
Stellar Tidal Streams As Cosmological Diagnostics: Comparing Data and Simulations at Low Galactic Scales
RUPRECHT-KARLS-UNIVERSITÄT HEIDELBERG DOCTORAL THESIS Stellar Tidal Streams as Cosmological Diagnostics: Comparing data and simulations at low galactic scales Author: Referees: Gustavo MORALES Prof. Dr. Eva K. GREBEL Prof. Dr. Volker SPRINGEL Astronomisches Rechen-Institut Heidelberg Graduate School of Fundamental Physics Department of Physics and Astronomy 14th May, 2018 ii DISSERTATION submitted to the Combined Faculties of the Natural Sciences and Mathematics of the Ruperto-Carola-University of Heidelberg, Germany for the degree of DOCTOR OF NATURAL SCIENCES Put forward by GUSTAVO MORALES born in Copiapo ORAL EXAMINATION ON JULY 26, 2018 iii Stellar Tidal Streams as Cosmological Diagnostics: Comparing data and simulations at low galactic scales Referees: Prof. Dr. Eva K. GREBEL Prof. Dr. Volker SPRINGEL iv NOTE: Some parts of the written contents of this thesis have been adapted from a paper submitted as a co-authored scientific publication to the Astronomy & Astrophysics Journal: Morales et al. (2018). v NOTE: Some parts of this thesis have been adapted from a paper accepted for publi- cation in the Astronomy & Astrophysics Journal: Morales, G. et al. (2018). “Systematic search for tidal features around nearby galaxies: I. Enhanced SDSS imaging of the Local Volume". arXiv:1804.03330. DOI: 10.1051/0004-6361/201732271 vii Abstract In hierarchical models of galaxy formation, stellar tidal streams are expected around most galaxies. Although these features may provide useful diagnostics of the LCDM model, their observational properties remain poorly constrained. Statistical analysis of the counts and properties of such features is of interest for a direct comparison against results from numeri- cal simulations. In this work, we aim to study systematically the frequency of occurrence and other observational properties of tidal features around nearby galaxies. -
Dark Matter: the Evidence from Astronomy, Astrophysics and Cosmology Matts Roos University of Helsinki [email protected]
Dark Matter: The evidence from astronomy, astrophysics and cosmology Matts Roos University of Helsinki [email protected] Dark matter has been introduced to explain many independent gravitational effects at different astronomical scales, even at cosmological scales. This review describes more than ten such effects. It is intended for an audience with little or no knowledge of astrophysics or cosmology. ContentsContents I. Stars near the Galactic disk II. Virially bound systems III. Rotation curves of spiral galaxies IV. Small galaxy groups emitting X-rays V. Mass to luminosity ratios VI. Mass autocorrelation functions VII. Strong and weak lensing VIII. Cosmic Microwave Background IX. Baryonic acoustic oscillations X. Galaxy formation in purely baryonic matter XI. Large Scale Structures simulated XII. Dark matter from overall fits XIII. Merging galaxy clusters XIV. Conclusions II StarsStars nearnear thethe GalacticGalactic diskdisk ? J. H. Oort in 1932 analyzed vertical motions of stars near the Galactic disk and calculated the vertical acceleration of matter. ? Their density and velocity dispersion define the temperature of a ”star atmosphere” bound by a gravitational potential. ? This contradicted grossly the expectations: the density due to known stars was not sufficient: the Galaxy should rapidly be losing stars. ? This was the first indication for the possible existence of dark matter in the Galaxy. ? He determined the mass of the Milky Way: 1011 solar masses, today understood to be mainly in the halo, not in the disk. ? But dark -
Naming the Extrasolar Planets
Naming the extrasolar planets W. Lyra Max Planck Institute for Astronomy, K¨onigstuhl 17, 69177, Heidelberg, Germany [email protected] Abstract and OGLE-TR-182 b, which does not help educators convey the message that these planets are quite similar to Jupiter. Extrasolar planets are not named and are referred to only In stark contrast, the sentence“planet Apollo is a gas giant by their assigned scientific designation. The reason given like Jupiter” is heavily - yet invisibly - coated with Coper- by the IAU to not name the planets is that it is consid- nicanism. ered impractical as planets are expected to be common. I One reason given by the IAU for not considering naming advance some reasons as to why this logic is flawed, and sug- the extrasolar planets is that it is a task deemed impractical. gest names for the 403 extrasolar planet candidates known One source is quoted as having said “if planets are found to as of Oct 2009. The names follow a scheme of association occur very frequently in the Universe, a system of individual with the constellation that the host star pertains to, and names for planets might well rapidly be found equally im- therefore are mostly drawn from Roman-Greek mythology. practicable as it is for stars, as planet discoveries progress.” Other mythologies may also be used given that a suitable 1. This leads to a second argument. It is indeed impractical association is established. to name all stars. But some stars are named nonetheless. In fact, all other classes of astronomical bodies are named. -
Active Galactic Nuclei and Their Neighbours
CCD Photometric Observations of Active Galactic Nuclei and their Neighbours by Traianou Efthalia A dissertation submitted in partial fulfillment of the requirements for the degree of Ptychion (Physics) in Aristotle University of Thessaloniki September 2016 Supervisor: Manolis Plionis, Professor To my loved ones Many thanks to: Manolis Plionis for accepting to be my thesis adviser. ii TABLE OF CONTENTS DEDICATION :::::::::::::::::::::::::::::::::: ii LIST OF FIGURES ::::::::::::::::::::::::::::::: v LIST OF TABLES :::::::::::::::::::::::::::::::: ix LIST OF APPENDICES :::::::::::::::::::::::::::: x ABSTRACT ::::::::::::::::::::::::::::::::::: xi CHAPTER I. Introduction .............................. 1 II. Active Galactic Nuclei ........................ 4 2.1 Early History of AGN’s ..................... 4 2.2 AGN Phenomenology ...................... 7 2.2.1 Seyfert Galaxies ................... 7 2.2.2 Low Ionization Nuclear Emission-Line Regions(LINERS) 10 2.2.3 ULIRGS ........................ 11 2.2.4 Radio Galaxies .................... 12 2.2.5 Quasars or QSO’s ................... 14 2.2.6 Blazars ......................... 15 2.3 The Unification Paradigm .................... 16 2.4 Beyond the Unified Model ................... 18 III. Research Goal and Methodology ................. 21 3.1 Torus ............................... 21 3.2 Ha Balmer Line ......................... 23 3.3 Galaxy-Galaxy Interactions ................... 25 3.4 Our Aim ............................. 27 iii IV. Observations .............................. 29 4.1 The Telescope -
Magnetism, Dynamo Action and the Solar-Stellar Connection
Living Rev. Sol. Phys. (2017) 14:4 DOI 10.1007/s41116-017-0007-8 REVIEW ARTICLE Magnetism, dynamo action and the solar-stellar connection Allan Sacha Brun1 · Matthew K. Browning2 Received: 23 August 2016 / Accepted: 28 July 2017 © The Author(s) 2017. This article is an open access publication Abstract The Sun and other stars are magnetic: magnetism pervades their interiors and affects their evolution in a variety of ways. In the Sun, both the fields themselves and their influence on other phenomena can be uncovered in exquisite detail, but these observations sample only a moment in a single star’s life. By turning to observa- tions of other stars, and to theory and simulation, we may infer other aspects of the magnetism—e.g., its dependence on stellar age, mass, or rotation rate—that would be invisible from close study of the Sun alone. Here, we review observations and theory of magnetism in the Sun and other stars, with a partial focus on the “Solar-stellar connec- tion”: i.e., ways in which studies of other stars have influenced our understanding of the Sun and vice versa. We briefly review techniques by which magnetic fields can be measured (or their presence otherwise inferred) in stars, and then highlight some key observational findings uncovered by such measurements, focusing (in many cases) on those that offer particularly direct constraints on theories of how the fields are built and maintained. We turn then to a discussion of how the fields arise in different objects: first, we summarize some essential elements of convection and dynamo theory, includ- ing a very brief discussion of mean-field theory and related concepts. -
Arxiv:2105.11583V2 [Astro-Ph.EP] 2 Jul 2021 Keck-HIRES, APF-Levy, and Lick-Hamilton Spectrographs
Draft version July 6, 2021 Typeset using LATEX twocolumn style in AASTeX63 The California Legacy Survey I. A Catalog of 178 Planets from Precision Radial Velocity Monitoring of 719 Nearby Stars over Three Decades Lee J. Rosenthal,1 Benjamin J. Fulton,1, 2 Lea A. Hirsch,3 Howard T. Isaacson,4 Andrew W. Howard,1 Cayla M. Dedrick,5, 6 Ilya A. Sherstyuk,1 Sarah C. Blunt,1, 7 Erik A. Petigura,8 Heather A. Knutson,9 Aida Behmard,9, 7 Ashley Chontos,10, 7 Justin R. Crepp,11 Ian J. M. Crossfield,12 Paul A. Dalba,13, 14 Debra A. Fischer,15 Gregory W. Henry,16 Stephen R. Kane,13 Molly Kosiarek,17, 7 Geoffrey W. Marcy,1, 7 Ryan A. Rubenzahl,1, 7 Lauren M. Weiss,10 and Jason T. Wright18, 19, 20 1Cahill Center for Astronomy & Astrophysics, California Institute of Technology, Pasadena, CA 91125, USA 2IPAC-NASA Exoplanet Science Institute, Pasadena, CA 91125, USA 3Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA 94305, USA 4Department of Astronomy, University of California Berkeley, Berkeley, CA 94720, USA 5Cahill Center for Astronomy & Astrophysics, California Institute of Technology, Pasadena, CA 91125, USA 6Department of Astronomy & Astrophysics, The Pennsylvania State University, 525 Davey Lab, University Park, PA 16802, USA 7NSF Graduate Research Fellow 8Department of Physics & Astronomy, University of California Los Angeles, Los Angeles, CA 90095, USA 9Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA 10Institute for Astronomy, University of Hawai`i, -
On the X-Ray and Optical Properties of the Be Star HD 110432: a Very Hard-Thermal X-Ray Emitter
On the X-ray and optical properties of the Be star HD 110432: a very hard-thermal X-ray emitter Raimundo LOPES DE OLIVEIRA Filho (1,2), Christian MOTCH (2), Myron A. SMITH (3), Ignacio NEGUERUELA (4) and Jose M. TORREJON (4) (1) Instituto de Astronomia, Geof'{i}sica e Ci^encias Atmosf'ericas, Universidade de S~ao Paulo, Brazil; (2) Observatoire Astronomique de Strasbourg, Universit'e Louis Pasteur, France; (3) Catholic University of America, USA; (4) Universidad de Alicante, Spain HD 110432 is the first proposed, and best studied, member of a growing group of Be stars with X-ray properties similar to $gamma$ Cas. These stars exhibit hard-thermal X-rays that are variable on all measurable timescales. This emission contrasts with the soft emission of ``normal" massive stars and with the nonthermal emission of all well known Be/X-ray binaries -- so far, all Be + neutron star systems. In this work we present X-ray spectral and timing properties of HD 110432 from three XMM-{it Newton} observations in addition to new optical spectroscopic observations. Like $gamma$ Cas, the X-rays of HD 110432 appear to have a thermal origin, as supported by strongly ionized FeXXV and FeXXVI lines detected in emission. A fluorescent iron feature at 6.4 keV is present in all observations, while the FeXXVI Ly$beta$ line is present in two of them. Its X-ray spectrum, complex and time variable, is well described in each observation by three thermal plasmas with temperatures ranging between 0.2--0.7, 3--6, and 16--37 keV. -
UC Irvine UC Irvine Previously Published Works
UC Irvine UC Irvine Previously Published Works Title Astrophysics in 2006 Permalink https://escholarship.org/uc/item/5760h9v8 Journal Space Science Reviews, 132(1) ISSN 0038-6308 Authors Trimble, V Aschwanden, MJ Hansen, CJ Publication Date 2007-09-01 DOI 10.1007/s11214-007-9224-0 License https://creativecommons.org/licenses/by/4.0/ 4.0 Peer reviewed eScholarship.org Powered by the California Digital Library University of California Space Sci Rev (2007) 132: 1–182 DOI 10.1007/s11214-007-9224-0 Astrophysics in 2006 Virginia Trimble · Markus J. Aschwanden · Carl J. Hansen Received: 11 May 2007 / Accepted: 24 May 2007 / Published online: 23 October 2007 © Springer Science+Business Media B.V. 2007 Abstract The fastest pulsar and the slowest nova; the oldest galaxies and the youngest stars; the weirdest life forms and the commonest dwarfs; the highest energy particles and the lowest energy photons. These were some of the extremes of Astrophysics 2006. We attempt also to bring you updates on things of which there is currently only one (habitable planets, the Sun, and the Universe) and others of which there are always many, like meteors and molecules, black holes and binaries. Keywords Cosmology: general · Galaxies: general · ISM: general · Stars: general · Sun: general · Planets and satellites: general · Astrobiology · Star clusters · Binary stars · Clusters of galaxies · Gamma-ray bursts · Milky Way · Earth · Active galaxies · Supernovae 1 Introduction Astrophysics in 2006 modifies a long tradition by moving to a new journal, which you hold in your (real or virtual) hands. The fifteen previous articles in the series are referenced oc- casionally as Ap91 to Ap05 below and appeared in volumes 104–118 of Publications of V. -
Measuring the Velocity Field from Type Ia Supernovae in an LSST-Like Sky
Prepared for submission to JCAP Measuring the velocity field from type Ia supernovae in an LSST-like sky survey Io Odderskov,a Steen Hannestada aDepartment of Physics and Astronomy University of Aarhus, Ny Munkegade, Aarhus C, Denmark E-mail: [email protected], [email protected] Abstract. In a few years, the Large Synoptic Survey Telescope will vastly increase the number of type Ia supernovae observed in the local universe. This will allow for a precise mapping of the velocity field and, since the source of peculiar velocities is variations in the density field, cosmological parameters related to the matter distribution can subsequently be extracted from the velocity power spectrum. One way to quantify this is through the angular power spectrum of radial peculiar velocities on spheres at different redshifts. We investigate how well this observable can be measured, despite the problems caused by areas with no information. To obtain a realistic distribution of supernovae, we create mock supernova catalogs by using a semi-analytical code for galaxy formation on the merger trees extracted from N-body simulations. We measure the cosmic variance in the velocity power spectrum by repeating the procedure many times for differently located observers, and vary several aspects of the analysis, such as the observer environment, to see how this affects the measurements. Our results confirm the findings from earlier studies regarding the precision with which the angular velocity power spectrum can be determined in the near future. This level of precision has been found to imply, that the angular velocity power spectrum from type Ia supernovae is competitive in its potential to measure parameters such as σ8. -
April 1999 the Albuquerque Astronomical Society News Letter
Back to List of Newsletters April 1999 This special HTML version of our newsletter contains most of the information published in the "real" Sidereal Times . All information is copyrighted by TAAS. Permission for other amateur astronomy associations is granted provided proper credit is given. Table of Contents Departments Calendars o Calendar of Events for May1999 o Calendar of Events for June 1999 Lead Story: Beth Fernandez is National Young Astronomer Presidents Update Constellation TAAS The Board Meeting Observatory Committee Last Month's General Meeting Recap Next General Meeting Observer's Page What's Up for May Ask the Experts: How can I measure the focal length of my mirror accurately? The Kids' Corner ATM Corner Star Myths UNM Campus Observatory Report Docent News Astronomy 101 Astronomical Computing Internet Info Chaco Canyon Observatory Trivia Question Letters to the Editor Classified Ads Feature Stories Oak Flat Astronomy Day '99 Space Day '99 We need Eyepieces!!! 1999 Broline Science Fair Awards Please note: TAAS offers a Safety Escort Service to those attending monthly meetings on the UNM campus. Please contact the President or any board member during social hour after the meeting if you wish assistance, and a Society member will happily accompany you to your car. Calendars Calendar Images May Calendar o GIF version (~67K) o PDF version (~46K) June Calendar o GIF version (~44K) o PDF version (~46K) TAAS Calendar page May 1999 1 Sat * General Meeting, 7 pm, Regener Hall Mars nearest to Earth (.578 au at noon) 2 Sun Moon at apogee 63.7 earth-radii at 1 am 3 Mon * Alamosa Elementary School 4 Tue 5 Wed Venus becomes nearer than 1 au to Earth (8 am) 6 Thu Neptune stationary in RA (3 pm). -
Hubble Law: Measure and Interpretation
Special Issue on the foundations of astrophysics and cosmology manuscript No. (will be inserted by the editor) Hubble law : measure and interpretation Paturel Georges · Teerikorpi Pekka · Baryshev Yurij Received: date / Accepted: date Abstract We have had the chance to live through a fascinating revolution in measuring the fundamental empirical cosmological Hubble law. The key progress is analysed : 1) improvement of observational means (ground-based radio and optical observations, space missions) ; 2) understanding of the bi- ases that affect both distant and local determinations of the Hubble constant; 3) new theoretical and observational results. These circumstances encourage us to take a critical look at some facts and ideas related to the cosmological red-shift. This is important because we are probably on the eve of a new under- standing of our Universe, heralded by the need to interpret some cosmological key observations in terms of unknown processes and substances. 1 Introduction This paper is a short review concerning the study of the Hubble law. The purpose is to give an overview of the evolution of cosmology with a presentation as simple as possible. In the present section, we give a brief description of the first steps in both conceptual and technical improvements that has led us to the present situation. In section 2, we explain the biases that plagued for decades the G. Paturel Retired from Universite Claude-Bernard, Observatoire de Lyon, 69230 Saint-Genis Laval, France Tel.: +334 78560474 E-mail: [email protected] P. Teerikorpi Tuorla Observatory, Department of Physics and Astronomy, University of Turku, 21500 Pi- ikki¨o, Finland E-mail: pekkatee@utu.fi arXiv:1801.00128v1 [astro-ph.CO] 30 Dec 2017 Y.