The Never-Ending Realm of Galaxies
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Cosmicflows-3: Cosmography of the Local Void
Draft version May 22, 2019 Preprint typeset using LATEX style AASTeX6 v. 1.0 COSMICFLOWS-3: COSMOGRAPHY OF THE LOCAL VOID R. Brent Tully, Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822, USA Daniel Pomarede` Institut de Recherche sur les Lois Fondamentales de l'Univers, CEA, Universite' Paris-Saclay, 91191 Gif-sur-Yvette, France Romain Graziani University of Lyon, UCB Lyon 1, CNRS/IN2P3, IPN Lyon, France Hel´ ene` M. Courtois University of Lyon, UCB Lyon 1, CNRS/IN2P3, IPN Lyon, France Yehuda Hoffman Racah Institute of Physics, Hebrew University, Jerusalem, 91904 Israel Edward J. Shaya University of Maryland, Astronomy Department, College Park, MD 20743, USA ABSTRACT Cosmicflows-3 distances and inferred peculiar velocities of galaxies have permitted the reconstruction of the structure of over and under densities within the volume extending to 0:05c. This study focuses on the under dense regions, particularly the Local Void that lies largely in the zone of obscuration and consequently has received limited attention. Major over dense structures that bound the Local Void are the Perseus-Pisces and Norma-Pavo-Indus filaments sepa- rated by 8,500 km s−1. The void network of the universe is interconnected and void passages are found from the Local Void to the adjacent very large Hercules and Sculptor voids. Minor filaments course through voids. A particularly interesting example connects the Virgo and Perseus clusters, with several substantial galaxies found along the chain in the depths of the Local Void. The Local Void has a substantial dynamical effect, causing a deviant motion of the Local Group of 200 − 250 km s−1. -
Arxiv:1904.07129V1 [Astro-Ph.GA] 15 Apr 2019
Draft version April 16, 2019 Preprint typeset using LATEX style emulateapj v. 12/16/11 SPIRE SPECTROSCOPY OF EARLY TYPE GALAXIES Ryen Carl Lapham and Lisa M. Young Physics Department, New Mexico Institute of Mining and Technology, 801 Leroy Place, Socorro, NM 87801; [email protected], [email protected] Draft version April 16, 2019 ABSTRACT We present SPIRE spectroscopy for 9 early-type galaxies (ETGs) representing the most CO-rich and far-infrared (FIR) bright galaxies of the volume-limited Atlas3D sample. Our data include detections of mid to high J CO transitions (J=4-3 to J=13-12) and the [C I] (1-0) and (2-1) emission lines. CO spectral line energy distributions (SLEDs) for our ETGs indicate low gas excitation, barring NGC 1266. We use the [C I] emission lines to determine the excitation temperature of the neutral gas, as well as estimate the mass of molecular hydrogen. The masses agree well with masses derived from CO, making this technique very promising for high redshift galaxies. We do not find a trend between the [N II] 205 flux and the infrared luminosity, but we do find that the [N II] 205/CO(6-5) line ratio is correlated with the 60/100 µm Infrared Astronomical Satellite (IRAS) colors. Thus the [N II] 205/CO(6-5) ratio can be used to infer a dust temperature, and hence the intensity of the interstellar radiation field (ISRF). Photodissociation region (PDR) models show that use of [C I] and CO lines in addition to the typical [C II], [O I], and FIR fluxes drive the model solutions to higher densities and lower values of G0. -
Thesis University of Western Australia
Kinematic and Environmental Regulation of Atomic Gas in Galaxies Jie Li March 2019 Master Thesis University of Western Australia Supervisors: Dr. Danail Obreschkow Dr. Claudia Lagos Dr. Charlotte Welker 20/05/2019 Acknowledgments I would like to thank my supervisors Danail Obreschkow, Claudia Lagos and Charlotte Welker for their guidance and support during this project, Luca Cortese, Robert Dˇzudˇzar and Garima Chauhan for their useful suggestions, my parents for giving me financial support and love, and ICRAR for o↵ering an open and friendly environments. Abstract Recent studies of neutral atomic hydrogen (H i) in nearby galaxies find that all isolated star-forming disk-dominated galaxies, from low-mass dwarfs to massive spirals systems, are H i saturated, in that they carry roughly (within a factor 1.5) as much H i fraction as permitted before this gas becomes gravitationally unstable. By taking this H i saturation for granted, the atomic gas fraction fatm of galactic disks can be predicted as a function of a stability parameter q j/M,whereM and j are the baryonic mass and specific / angular momentum of the disk (Obreschkow et al., 2016). The (logarithmic) di↵erence ∆fq between this predictor and the observed atomic fraction can thus be seen as a physically motivated way of defining a ‘H i deficiency’. While isolated disk galaxies have ∆f 0, q ⇡ objects subject to environmental removal/suppression of H i are expected to have ∆fq > 0. Within this framework, we revisit the H i deficiencies of satellite galaxies in the Virgo cluster (from the VIVA sample), as well as in clusters of the EAGLE simulation. -
Messier Objects
Messier Objects From the Stocker Astroscience Center at Florida International University Miami Florida The Messier Project Main contributors: • Daniel Puentes • Steven Revesz • Bobby Martinez Charles Messier • Gabriel Salazar • Riya Gandhi • Dr. James Webb – Director, Stocker Astroscience center • All images reduced and combined using MIRA image processing software. (Mirametrics) What are Messier Objects? • Messier objects are a list of astronomical sources compiled by Charles Messier, an 18th and early 19th century astronomer. He created a list of distracting objects to avoid while comet hunting. This list now contains over 110 objects, many of which are the most famous astronomical bodies known. The list contains planetary nebula, star clusters, and other galaxies. - Bobby Martinez The Telescope The telescope used to take these images is an Astronomical Consultants and Equipment (ACE) 24- inch (0.61-meter) Ritchey-Chretien reflecting telescope. It has a focal ratio of F6.2 and is supported on a structure independent of the building that houses it. It is equipped with a Finger Lakes 1kx1k CCD camera cooled to -30o C at the Cassegrain focus. It is equipped with dual filter wheels, the first containing UBVRI scientific filters and the second RGBL color filters. Messier 1 Found 6,500 light years away in the constellation of Taurus, the Crab Nebula (known as M1) is a supernova remnant. The original supernova that formed the crab nebula was observed by Chinese, Japanese and Arab astronomers in 1054 AD as an incredibly bright “Guest star” which was visible for over twenty-two months. The supernova that produced the Crab Nebula is thought to have been an evolved star roughly ten times more massive than the Sun. -
The Puzzling Nature of Dwarf-Sized Gas Poor Disk Galaxies
Dissertation submitted to the Department of Physics Combined Faculties of the Astronomy Division Natural Sciences and Mathematics University of Oulu Ruperto-Carola-University Oulu, Finland Heidelberg, Germany for the degree of Doctor of Natural Sciences Put forward by Joachim Janz born in: Heidelberg, Germany Public defense: January 25, 2013 in Oulu, Finland THE PUZZLING NATURE OF DWARF-SIZED GAS POOR DISK GALAXIES Preliminary examiners: Pekka Heinämäki Helmut Jerjen Opponent: Laura Ferrarese Joachim Janz: The puzzling nature of dwarf-sized gas poor disk galaxies, c 2012 advisors: Dr. Eija Laurikainen Dr. Thorsten Lisker Prof. Heikki Salo Oulu, 2012 ABSTRACT Early-type dwarf galaxies were originally described as elliptical feature-less galax- ies. However, later disk signatures were revealed in some of them. In fact, it is still disputed whether they follow photometric scaling relations similar to giant elliptical galaxies or whether they are rather formed in transformations of late- type galaxies induced by the galaxy cluster environment. The early-type dwarf galaxies are the most abundant galaxy type in clusters, and their low-mass make them susceptible to processes that let galaxies evolve. Therefore, they are well- suited as probes of galaxy evolution. In this thesis we explore possible relationships and evolutionary links of early- type dwarfs to other galaxy types. We observed a sample of 121 galaxies and obtained deep near-infrared images. For analyzing the morphology of these galaxies, we apply two-dimensional multicomponent fitting to the data. This is done for the first time for a large sample of early-type dwarfs. A large fraction of the galaxies is shown to have complex multicomponent structures. -
Modelling the Size Distribution of Cosmic Voids
Alma Mater Studiorum | Universita` di Bologna SCUOLA DI SCIENZE Corso di Laurea Magistrale in Astrofisica e Cosmologia Dipartimento di Fisica e Astronomia Modelling the size distribution of Cosmic Voids Tesi di Laurea Magistrale Candidato: Relatore: Tommaso Ronconi Lauro Moscardini Correlatori: Marco Baldi Federico Marulli Sessione I Anno Accademico 2015-2016 Contents Contentsi Introduction vii 1 The cosmological framework1 1.1 The Friedmann-Robertson-Walker metric...............2 1.1.1 The Hubble Law and the reddening of distant objects....4 1.1.2 Friedmann Equations......................5 1.1.3 Friedmann Models........................6 1.1.4 Flat VS Curved Universes....................8 1.2 The Standard Cosmological Model...................9 1.3 Jeans Theory and Expanding Universes................ 12 1.3.1 Instability in a Static Universe................. 13 1.3.2 Instability in an Expanding Universe.............. 14 1.3.3 Primordial Density Fluctuations................ 15 1.3.4 Non-Linear Evolution...................... 17 2 Cosmic Voids in the large scale structure 19 2.1 Spherical evolution............................ 20 2.1.1 Overdensities........................... 23 2.1.2 Underdensities.......................... 24 2.2 Excursion set formalism......................... 26 2.2.1 Press-Schechter halo mass function and exstension...... 29 2.3 Void size function............................. 31 2.3.1 Sheth and van de Weygaert model............... 33 2.3.2 Volume conserving model (Vdn)................ 35 2.4 Halo bias................................. 36 3 Methods 38 3.1 CosmoBolognaLib: C++ libraries for cosmological calculations... 38 3.2 N-body simulations............................ 39 3.2.1 The set of cosmological simulations............... 40 3.3 Void Finders............................... 42 3.4 From centres to spherical non-overlapped voids............ 43 3.4.1 Void centres........................... -
A Multimessenger View of Galaxies and Quasars from Now to Mid-Century M
A multimessenger view of galaxies and quasars from now to mid-century M. D’Onofrio 1;∗, P. Marziani 2;∗ 1 Department of Physics & Astronomy, University of Padova, Padova, Italia 2 National Institute for Astrophysics (INAF), Padua Astronomical Observatory, Italy Correspondence*: Mauro D’Onofrio [email protected] ABSTRACT In the next 30 years, a new generation of space and ground-based telescopes will permit to obtain multi-frequency observations of faint sources and, for the first time in human history, to achieve a deep, almost synoptical monitoring of the whole sky. Gravitational wave observatories will detect a Universe of unseen black holes in the merging process over a broad spectrum of mass. Computing facilities will permit new high-resolution simulations with a deeper physical analysis of the main phenomena occurring at different scales. Given these development lines, we first sketch a panorama of the main instrumental developments expected in the next thirty years, dealing not only with electromagnetic radiation, but also from a multi-messenger perspective that includes gravitational waves, neutrinos, and cosmic rays. We then present how the new instrumentation will make it possible to foster advances in our present understanding of galaxies and quasars. We focus on selected scientific themes that are hotly debated today, in some cases advancing conjectures on the solution of major problems that may become solved in the next 30 years. Keywords: galaxy evolution – quasars – cosmology – supermassive black holes – black hole physics 1 INTRODUCTION: TOWARD MULTIMESSENGER ASTRONOMY The development of astronomy in the second half of the XXth century followed two major lines of improvement: the increase in light gathering power (i.e., the ability to detect fainter objects), and the extension of the frequency domain in the electromagnetic spectrum beyond the traditional optical domain. -
Astrotalk: Behind the News Headlines
AstroTalk: Behind the news headlines Richard de Grijs (何锐思) (Macquarie University, Sydney, Australia) The Gaia ‘Sausage’ galaxy Our Milky Way galaxy has most likely collided or otherwise interacted with numerous other galaxies during its lifetime. Indeed, such interactions are common cosmic occurrences. Astronomers can deduce the history of mass accretion onto the Milky Way from a study of debris in the halo of the galaxy left as the tidal residue of such episodes. That approach has worked particularly well for studies of the most recent merger events, like the infall of the Sagittarius dwarf galaxy into the Milky Way’s centre a few billion years ago, which left tidal streamers of stars visiBle in galaxy maps. The damaging effects these encounters can cause to the Milky Way have, however, not been as well studied, and events even further in the past are even less obvious as they Become Blurred By the galaxy’s natural motions and evolution. Some episodes in the Milky Way’s history, however, were so cataclysmic that they are difficult to hide. Scientists have known for some time that the Milky Way’s halo of stars drastically changes in character with distance from the galactic centre, as revealed by the chemical composition—the ‘metallicity’—of the stars, the stellar motions, and the stellar density. Harvard astronomer Federico Marinacci and his colleagues recently analysed a suite of cosmological computer simulations and the galaxy interactions in them. In particular they analysed the history of galaxy halos as they evolved following a merger event. They concluded that six to ten Billion years ago the Milky Way merged in a head- on collision with a dwarf galaxy containing stars amounting to about one-to-ten billion solar masses, and that this collision could produce the character changes in stellar populations currently observed in the Milky Way’s stellar halo. -
THE 1000 BRIGHTEST HIPASS GALAXIES: H I PROPERTIES B
The Astronomical Journal, 128:16–46, 2004 July A # 2004. The American Astronomical Society. All rights reserved. Printed in U.S.A. THE 1000 BRIGHTEST HIPASS GALAXIES: H i PROPERTIES B. S. Koribalski,1 L. Staveley-Smith,1 V. A. Kilborn,1, 2 S. D. Ryder,3 R. C. Kraan-Korteweg,4 E. V. Ryan-Weber,1, 5 R. D. Ekers,1 H. Jerjen,6 P. A. Henning,7 M. E. Putman,8 M. A. Zwaan,5, 9 W. J. G. de Blok,1,10 M. R. Calabretta,1 M. J. Disney,10 R. F. Minchin,10 R. Bhathal,11 P. J. Boyce,10 M. J. Drinkwater,12 K. C. Freeman,6 B. K. Gibson,2 A. J. Green,13 R. F. Haynes,1 S. Juraszek,13 M. J. Kesteven,1 P. M. Knezek,14 S. Mader,1 M. Marquarding,1 M. Meyer,5 J. R. Mould,15 T. Oosterloo,16 J. O’Brien,1,6 R. M. Price,7 E. M. Sadler,13 A. Schro¨der,17 I. M. Stewart,17 F. Stootman,11 M. Waugh,1, 5 B. E. Warren,1, 6 R. L. Webster,5 and A. E. Wright1 Received 2002 October 30; accepted 2004 April 7 ABSTRACT We present the HIPASS Bright Galaxy Catalog (BGC), which contains the 1000 H i brightest galaxies in the southern sky as obtained from the H i Parkes All-Sky Survey (HIPASS). The selection of the brightest sources is basedontheirHi peak flux density (Speak k116 mJy) as measured from the spatially integrated HIPASS spectrum. 7 ; 10 The derived H i masses range from 10 to 4 10 M . -
1501.01010V1.Pdf
Draft version January 7, 2015 Preprint typeset using LATEX style emulateapj v. 5/2/11 JET-ISM INTERACTION IN THE RADIO GALAXY 3C293: JET-DRIVEN SHOCKS HEAT ISM TO POWER X-RAY AND MOLECULAR H2 EMISSION L. Lanz1, P. M. Ogle1, D. Evans2, P. N. Appleton3, P. Guillard4, B. Emonts5 Draft version January 7, 2015 ABSTRACT We present a 70ks Chandra observation of the radio galaxy 3C 293. This galaxy belongs to the class of molecular hydrogen emission galaxies (MOHEGs) that have very luminous emission from warm molecular hydrogen. In radio galaxies, the molecular gas appears to be heated by jet-driven shocks, but exactly how this mechanism works is still poorly understood. With Chandra, we observe X-ray emission from the jets within the host galaxy and along the 100 kpc radio jets. We model the X-ray spectra of the nucleus, the inner jets, and the X-ray features along the extended radio jets. Both the nucleus and the inner jets show evidence of 107 K shock-heated gas. The kinetic power of the jets is more than sufficient to heat the X-ray emitting gas within the host galaxy. The thermal X-ray and warm H2 luminosities of 3C 293 are similar, indicating similar masses of X-ray hot gas and warm molecular gas. This is consistent with a picture where both derive from a multiphase, shocked interstellar medium (ISM). We find that radio-loud MOHEGs that are not brightest cluster galaxies (BCGs), like 3C 293, typically have LH2 /LX ∼ 1 and MH2 /MX ∼ 1, whereas MOHEGs that are BCGs have LH2 /LX ∼ 0.01 and MH2 /MX ∼ 0.01. -
An Overview of New Worlds, New Horizons in Astronomy and Astrophysics About the National Academies
2020 VISION An Overview of New Worlds, New Horizons in Astronomy and Astrophysics About the National Academies The National Academies—comprising the National Academy of Sciences, the National Academy of Engineering, the Institute of Medicine, and the National Research Council—work together to enlist the nation’s top scientists, engineers, health professionals, and other experts to study specific issues in science, technology, and medicine that underlie many questions of national importance. The results of their deliberations have inspired some of the nation’s most significant and lasting efforts to improve the health, education, and welfare of the United States and have provided independent advice on issues that affect people’s lives worldwide. To learn more about the Academies’ activities, check the website at www.nationalacademies.org. Copyright 2011 by the National Academy of Sciences. All rights reserved. Printed in the United States of America This study was supported by Contract NNX08AN97G between the National Academy of Sciences and the National Aeronautics and Space Administration, Contract AST-0743899 between the National Academy of Sciences and the National Science Foundation, and Contract DE-FG02-08ER41542 between the National Academy of Sciences and the U.S. Department of Energy. Support for this study was also provided by the Vesto Slipher Fund. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and do not necessarily reflect the views of the agencies that provided support for the project. 2020 VISION An Overview of New Worlds, New Horizons in Astronomy and Astrophysics Committee for a Decadal Survey of Astronomy and Astrophysics ROGER D. -
Icecube Searches for Neutrinos from Dark Matter Annihilations in the Sun and Cosmic Accelerators
UNIVERSITE´ DE GENEVE` FACULTE´ DES SCIENCES Section de physique Professeur Teresa Montaruli D´epartement de physique nucl´eaireet corpusculaire IceCube searches for neutrinos from dark matter annihilations in the Sun and cosmic accelerators. THESE` pr´esent´ee`ala Facult´edes sciences de l'Universit´ede Gen`eve pour obtenir le grade de Docteur `essciences, mention physique par M. Rameez de Kozhikode, Kerala (India) Th`eseN◦ 4923 GENEVE` 2016 i Declaration of Authorship I, Mohamed Rameez, declare that this thesis titled, 'IceCube searches for neutrinos from dark matter annihilations in the Sun and cosmic accelerators.' and the work presented in it are my own. I confirm that: This work was done wholly or mainly while in candidature for a research degree at this University. Where any part of this thesis has previously been submitted for a degree or any other qualifica- tion at this University or any other institution, this has been clearly stated. Where I have consulted the published work of others, this is always clearly attributed. Where I have quoted from the work of others, the source is always given. With the exception of such quotations, this thesis is entirely my own work. I have acknowledged all main sources of help. Where the thesis is based on work done by myself jointly with others, I have made clear exactly what was done by others and what I have contributed myself. Signed: Date: 27 April 2016 ii UNIVERSITE´ DE GENEVE` Abstract Section de Physique D´epartement de physique nucl´eaireet corpusculaire Doctor of Philosophy IceCube searches for neutrinos from dark matter annihilations in the Sun and cosmic accelerators.