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Observational Studies of the Galaxy Peculiar Velocity Field
OBSERVATIONAL STUDIES OF THE GALAXY PECULIAR VELOCITY FIELD by Philip Andrew James Astrophysics Group Blackett Laboratory Imperial College of Science, Technology and Medicine London SW7 2BZ A thesis submitted for the degree of Doctor of Philosophy of the University of London and for the Diploma of Imperial College November 1988 1 ABSTRACT This thesis describes two observational studies of the peculiar velocity field of galaxies over scales of 50-100 Jr1 Mpc, and the consequences of these measurements for cosmological theories. An introduction is given to observational cosmology, emphasising the crucial questions of the nature of the dark matter and the formation of structure. The principal cosmological models are discussed, and the role of observations in developing these models is stressed. Consideration is given to those observations that are likely to prove good discriminators between the competing models, particular emphasis being given to studies of the coherent velocities of samples of galaxies. The first new study presented here uses optical photometry and redshifts, from the literature, for First Ranked Cluster Galaxies (FRCG’s). These galaxies are excellent standard candles, and thus ideal for peculiar velocity studies. A simple one dimensional analysis detects no relative motion between the Local Group of galaxies and 60 FRCG’s with redshifts of up to 15000 kms-1. This is shown to imply a streaming motion of the cluster galaxies of at least 600 kms_1 relative to the CBR. The second observational study is a reanalysis of the Rubin et al. (1976a,b) sample of Sc galaxies. Near-IR photometry is used in our reanalysis to minimise the effects of extinction and to facilitate the use of luminosity indicators in reducing the effects of selection biases. -
Curriculum Vitae Avishay Gal-Yam
January 27, 2017 Curriculum Vitae Avishay Gal-Yam Personal Name: Avishay Gal-Yam Current address: Department of Particle Physics and Astrophysics, Weizmann Institute of Science, 76100 Rehovot, Israel. Telephones: home: 972-8-9464749, work: 972-8-9342063, Fax: 972-8-9344477 e-mail: [email protected] Born: March 15, 1970, Israel Family status: Married + 3 Citizenship: Israeli Education 1997-2003: Ph.D., School of Physics and Astronomy, Tel-Aviv University, Israel. Advisor: Prof. Dan Maoz 1994-1996: B.Sc., Magna Cum Laude, in Physics and Mathematics, Tel-Aviv University, Israel. (1989-1993: Military service.) Positions 2013- : Head, Physics Core Facilities Unit, Weizmann Institute of Science, Israel. 2012- : Associate Professor, Weizmann Institute of Science, Israel. 2008- : Head, Kraar Observatory Program, Weizmann Institute of Science, Israel. 2007- : Visiting Associate, California Institute of Technology. 2007-2012: Senior Scientist, Weizmann Institute of Science, Israel. 2006-2007: Postdoctoral Scholar, California Institute of Technology. 2003-2006: Hubble Postdoctoral Fellow, California Institute of Technology. 1996-2003: Physics and Mathematics Research and Teaching Assistant, Tel Aviv University. Honors and Awards 2012: Kimmel Award for Innovative Investigation. 2010: Krill Prize for Excellence in Scientific Research. 2010: Isreali Physical Society (IPS) Prize for a Young Physicist (shared with E. Nakar). 2010: German Federal Ministry of Education and Research (BMBF) ARCHES Prize. 2010: Levinson Physics Prize. 2008: The Peter and Patricia Gruber Award. 2007: European Union IRG Fellow. 2006: “Citt`adi Cefal`u"Prize. 2003: Hubble Fellow. 2002: Tel Aviv U. School of Physics and Astronomy award for outstanding achievements. 2000: Colton Fellow. 2000: Tel Aviv U. School of Physics and Astronomy research and teaching excellence award. -
Comprehensive Broadband X-Ray and Multiwavelength Study of Active Galactic Nuclei in Local 57 Ultra/Luminous Infrared Galaxies Observed with Nustar And/Or Swift/BAT
Draft version July 26, 2021 Typeset using LATEX twocolumn style in AASTeX631 Comprehensive Broadband X-ray and Multiwavelength Study of Active Galactic Nuclei in Local 57 Ultra/luminous Infrared Galaxies Observed with NuSTAR and/or Swift/BAT Satoshi Yamada ,1 Yoshihiro Ueda ,1 Atsushi Tanimoto ,2 Masatoshi Imanishi ,3, 4 Yoshiki Toba ,1, 5 Claudio Ricci ,6, 7, 8 and George C. Privon 9 1Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan 2Department of Physics, The University of Tokyo, Tokyo 113-0033, Japan 3National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo 181-8588, Japan 4Department of Astronomical Science, Graduate University for Advanced Studies (SOKENDAI), 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan 5Research Center for Space and Cosmic Evolution, Ehime University, 2-5 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan 6N´ucleo de Astronom´ıade la Facultad de Ingenier´ıa,Universidad Diego Portales, Av. Ej´ercito Libertador 441, Santiago, Chile 7Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871, People's Republic of China 8George Mason University, Department of Physics & Astronomy, MS 3F3, 4400 University Drive, Fairfax, VA 22030, USA 9National Radio Astronomy Observatory, 520 Edgemont Rd, Charlottesville, VA 22903, USA (Received April 13, 2021; Revised June 11, 2021; Accepted Jul, 2021) ABSTRACT We perform a systematic X-ray spectroscopic analysis of 57 local ultra/luminous infrared galaxy systems (containing 84 individual galaxies) observed with Nuclear Spectroscopic Telescope Array and/or Swift/BAT. Combining soft X-ray data obtained with Chandra, XMM-Newton, Suzaku and/or Swift/XRT, we identify 40 hard (>10 keV) X-ray detected active galactic nuclei (AGNs) and con- strain their torus parameters with the X-ray clumpy torus model XCLUMPY (Tanimoto et al. -
Bias Mitigation in Galaxy Zoo Using Machine Learning Techniques
UC Irvine UC Irvine Electronic Theses and Dissertations Title Bias Mitigation in Galaxy Zoo Using Machine Learning Techniques Permalink https://escholarship.org/uc/item/7241p065 Author Silva do Nascimento Neto, Pedro Publication Date 2019 License https://creativecommons.org/licenses/by/4.0/ 4.0 Peer reviewed|Thesis/dissertation eScholarship.org Powered by the California Digital Library University of California UNIVERSITY OF CALIFORNIA, IRVINE Bias Mitigation in Galaxy Zoo Using Machine Learning Techniques DISSERTATION submitted in partial satisfaction of the requirements for the degree of DOCTOR OF PHILOSOPHY in Computer Science by Pedro Silva do Nascimento Neto Dissertation Committee: Professor Wayne Hayes, Chair Professor Aaron Barth Professor Eric Mjolsness 2019 c 2019 Pedro Silva do Nascimento Neto DEDICATION To my beloved wife, Elise. ii TABLE OF CONTENTS Page LIST OF FIGURES v LIST OF TABLES x LIST OF ALGORITHMS xii ACKNOWLEDGMENTS xiii CURRICULUM VITAE xv ABSTRACT OF THE DISSERTATION xvii 1 Introduction 1 2 Spiral Galaxy Recognition Using Arm Analysis and Random Forests 4 2.1 Introduction . 5 2.1.1 Related Work . 8 2.1.2 Regression, Not Classification, Because Galaxy Morphology Is Contin- uous, Not Discrete . 11 2.2 Methods . 13 2.3 Results . 17 2.3.1 Features, Trees, and Forests . 17 2.3.2 Adding SpArcFiRe Features . 18 2.3.3 Feature Quality . 26 2.3.4 Comparison with Other Regression Methods . 28 2.4 Conclusions . 30 3 The Chirality Bias in Galaxy Zoo 1 32 3.1 Introduction . 33 3.2 Nature of the bias . 36 3.2.1 More S-wise than Z-wise spins for all values of \spirality" . -
Understanding the H2/HI Ratio in Galaxies 3
Mon. Not. R. Astron. Soc. 394, 1857–1874 (2009) Printed 6 August 2021 (MN LATEX style file v2.2) Understanding the H2/HI Ratio in Galaxies D. Obreschkow and S. Rawlings Astrophysics, Department of Physics, University of Oxford, Keble Road, Oxford, OX1 3RH, UK Accepted 2009 January 12 ABSTRACT galaxy We revisit the mass ratio Rmol between molecular hydrogen (H2) and atomic hydrogen (HI) in different galaxies from a phenomenological and theoretical viewpoint. First, the local H2- mass function (MF) is estimated from the local CO-luminosity function (LF) of the FCRAO Extragalactic CO-Survey, adopting a variable CO-to-H2 conversion fitted to nearby observa- 5 1 tions. This implies an average H2-density ΩH2 = (6.9 2.7) 10− h− and ΩH2 /ΩHI = 0.26 0.11 ± · galaxy ± in the local Universe. Second, we investigate the correlations between Rmol and global galaxy properties in a sample of 245 local galaxies. Based on these correlations we intro- galaxy duce four phenomenological models for Rmol , which we apply to estimate H2-masses for galaxy each HI-galaxy in the HIPASS catalog. The resulting H2-MFs (one for each model for Rmol ) are compared to the reference H2-MF derived from the CO-LF, thus allowing us to determine the Bayesian evidence of each model and to identify a clear best model, in which, for spi- galaxy ral galaxies, Rmol negatively correlates with both galaxy Hubble type and total gas mass. galaxy Third, we derive a theoretical model for Rmol for regular galaxies based on an expression for their axially symmetric pressure profile dictating the degree of molecularization. -
The Applicability of Far-Infrared Fine-Structure Lines As Star Formation
A&A 568, A62 (2014) Astronomy DOI: 10.1051/0004-6361/201322489 & c ESO 2014 Astrophysics The applicability of far-infrared fine-structure lines as star formation rate tracers over wide ranges of metallicities and galaxy types? Ilse De Looze1, Diane Cormier2, Vianney Lebouteiller3, Suzanne Madden3, Maarten Baes1, George J. Bendo4, Médéric Boquien5, Alessandro Boselli6, David L. Clements7, Luca Cortese8;9, Asantha Cooray10;11, Maud Galametz8, Frédéric Galliano3, Javier Graciá-Carpio12, Kate Isaak13, Oskar Ł. Karczewski14, Tara J. Parkin15, Eric W. Pellegrini16, Aurélie Rémy-Ruyer3, Luigi Spinoglio17, Matthew W. L. Smith18, and Eckhard Sturm12 1 Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281 S9, 9000 Gent, Belgium e-mail: [email protected] 2 Zentrum für Astronomie der Universität Heidelberg, Institut für Theoretische Astrophysik, Albert-Ueberle Str. 2, 69120 Heidelberg, Germany 3 Laboratoire AIM, CEA, Université Paris VII, IRFU/Service d0Astrophysique, Bat. 709, 91191 Gif-sur-Yvette, France 4 UK ALMA Regional Centre Node, Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK 5 Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK 6 Laboratoire d0Astrophysique de Marseille − LAM, Université Aix-Marseille & CNRS, UMR7326, 38 rue F. Joliot-Curie, 13388 Marseille CEDEX 13, France 7 Astrophysics Group, Imperial College, Blackett Laboratory, Prince Consort Road, London SW7 2AZ, UK 8 European Southern Observatory, Karl -
1987Apj. . .318. .1613 the Astrophysical Journal, 318:161-174
.1613 The Astrophysical Journal, 318:161-174,1987 July 1 © 1987. The American Astronomical Society. All rights reserved. Printed in U.S.A. .318. 1987ApJ. A STUDY OF A FLUX-LIMITED SAMPLE OF IRAS GALAXIES1 Beverly J. Smith and S. G. Kleinmann University of Massachusetts J. P. Huchra Harvard-Smithsonian Center for Astrophysics AND F. J. Low Steward Observatory, University of Arizona Received 1986 September 3 ; accepted 1986 December 11 ABSTRACT We present results from a study of all 72 galaxies detected by IRAS in band 3 at flux levels >2 Jy and lying the region 8h < a < 17h, 23?5 < <5 < 32?5. Redshifts and accurate four-color IRAS photometry were 8 2 obtained for the entire sample. The 60 jtm luminosities of these galaxies lie in the range 4 x 10 (JF/o/100) L0 2 2 to 5 x lO^iTo/lOO) L0. The 60 jtm luminosity function at the high-luminosity end is proportional to L~ ; 10 below L = 10 L0 the luminosity function flattens. This is in agreement with previous results. We find a distinction between the morphology and infrared colors of the most luminous and the least luminous galaxies, leading to the suggestion that the observed luminosity function is produced by two different classes of objects. Comparisons between the selected IRAS galaxies and an optically complete sample taken from the CfA redshift survey show that they are more narrowly distributed in blue luminosity than those optically selected, in the sense that the IRAS sample includes few galaxies of low absolute blue luminosity. We also find that the space distribution of the two samples differ: the density enhancement of IRAS galaxies is only that of the optically selected galaxies in the core of the Coma Cluster, raising the question whether source counts of IRAS galaxies can be used to deduce the mass distribution in the universe. -
Physics ABSTRACT SIMULATION of INTERACTING GALAXY PAIR ARP
Research Paper Volume : 2 | Issue : 8 | August 2013 • ISSN No 2277 - 8179 Physics SIMULATION OF INTERACTING KEYWORDS : Arp 82, interacting galaxy GALAXY PAIR ARP 82 pairs, simulation of NGC2535 and NGC2536. Mariwan A. Rasheed Department of Physics, School of Science, University of Sulaimani ABSTRACT In the present work, the interaction between the two galaxies (NGC2535 and NGC2536) is simulated. And according to the simulation the interaction causes the two arc tails in the big galaxy NGC253, in which the southern tail of the galaxy is bigger than the northern tail and the southern tail is connected with the smaller galaxy NGC2336 through a bridge. For the initial conditions, such as mass ratio, distance, and the radius of the two galaxies that I have put in this work, gives a best picture of the two interacted galaxies which named as Arp 82. INTRODUCTION: by the gravitation, and the rings distort gradually, therefore the When galaxies interact they may merge into a large one or af- fect on each other without merging. These interactions make the whole disks of the galaxies reshape to produce the peculiar changes in the shape and the geometry of the two galaxies, in galaxies.distribution of particles of the outer rings dislocate at first, then which the result is the construction of peculiar galaxies. Such The initial conditions of mass, position, and the distance that have been put in this work are: peculiar galaxies are classified in atlas and catalog, Vorontsov- Velyaminov 1959 and 1977, Arp 1966, Karachentsev 1972. - Msun, radi- - 10 Arp 82 which can be considered as M51-type galaxies, Lauri For NGC2535 galaxy: the centroid mass =2.51×10 tails,kainen while et al, the 1998 second is an galaxy example is ofthe two small interacting galaxy which pair of known galax us=1.62 kpc, halo radius=9.72kpc.10 While for NGC 2536 galaxy: asies a NGC2535 companion and of NGC2536. -
Dark Energy and Extending the Geodesic Equations of Motion: Connecting the Galactic and Cosmological Length Scales
General Relativity and Gravitation (2011) DOI 10.1007/s10714-010-1043-z RESEARCHARTICLE A. D. Speliotopoulos Dark energy and extending the geodesic equations of motion: connecting the galactic and cosmological length scales Received: 23 May 2010 / Accepted: 16 June 2010 c The Author(s) 2010 Abstract Recently, an extension of the geodesic equations of motion using the Dark Energy length scale was proposed. Here, we apply this extension to analyz- ing the motion of test particles at the galactic scale and longer. A cosmological check of the extension is made using the observed rotational velocity curves and core sizes of 1,393 spiral galaxies. We derive the density profile of a model galaxy using this extension, and with it, we calculate σ8 to be 0.73±0.12; this is within +0.049 experimental error of the WMAP value of 0.761−0.048. We then calculate R200 to be 206±53 kpc, which is in reasonable agreement with observations. Keywords Dark energy, Galactic density profile, Density fluctuations, Extensions of the geodesic equations of motion, Galactic rotation curves 1 Introduction In a previous paper [1], we constructed an extension of the geodesic equations of motion (GEOM). This construction is possible because with the discovery of +0.82 −30 3 Dark Energy, ΛDE = (7.21−0.84) × 10 g/cm [2; 3; 4], there is now a length 1/2 scale, λDE = c/(ΛDEG) , associated with the universe. As this length scale is also not associated with the mass of any known particle, this extension does not violate various statements of the equivalence principle. -
Division C Rules Manual
Exploring the World of Science Division C Rules Manual Division C (Gr. 9-12) SCIENCE OLYMPIAD, INC. © 2020 WELCOME TO THE 2020 SCIENCE OLYMPIAD! This Rules Manual will help you prepare to compete in Invitational, Regional, State and National Tournaments held across the United States annually. Each Science Olympiad event has a corresponding page on the Science Olympiad national website complete with free resources, training handouts and useful links. All users of this manual are subject to the Terms of Use Agreement. To compete, users must first join the Science Olympiad program in their home state and become registered members. See our website for info on Membership, Policies and Terms of Use at www.soinc.org Division C (Grades 9-12) Membership Rules A team may have up to fifteen (15) members. A maximum of seven (7) 12th grade students is permitted on a Division C team. Division B (Grades 6-9) Membership Rules A team may have up to fifteen (15) members. A maximum of five (5) 9th grade students is permitted on a Division B team. Because middle schools that do not have grades 7, 8 or 9 are at a slight disadvantage, they may invite any combination of up to five (5) of their last year’s 6th, 7th or 8th grade students to be part of the team. Possible examples can be found on the Science Olympiad website. Students Below Grade Level Designations Science Olympiad encourages students to participate in the Division that matches current Science Olympiad grade level designations. However, to support the inclusion of students who wish to participate in Science Olympiad, schools with grade levels lower than those stated in a Division are permitted to invite members below the grade level designations. -
LARGE-SCALE STAR FORMATION TRIGGERING in the LOW-MASS ARP 82 SYSTEM: a NEARBY EXAMPLE of GALAXY DOWNSIZING BASED on UV/OPTICAL/MID-IR IMAGING Mark Hancock,1 Beverly J
The Astronomical Journal, 133:676–693, 2007 February # 2007. The American Astronomical Society. All rights reserved. Printed in U.S.A. LARGE-SCALE STAR FORMATION TRIGGERING IN THE LOW-MASS ARP 82 SYSTEM: A NEARBY EXAMPLE OF GALAXY DOWNSIZING BASED ON UV/OPTICAL/MID-IR IMAGING Mark Hancock,1 Beverly J. Smith,1 Curtis Struck,2 Mark L. Giroux,1 Philip N. Appleton,3 Vassilis Charmandaris,4,5,6 and William T. Reach3 Received 2006 August 3; accepted 2006 October 12 ABSTRACT As part of our Spitzer Spirals, Bridges, and Tails project to help understand the effects of galaxy interactions on star formation, we analyze Galaxy Evolution Explorer UV, Southeastern Association for Research in Astronomy optical, and Spitzer IR images of the interacting galaxy pair Arp 82 (NGC 2535/6) and compare to a numerical simulation of the interaction. We investigate the multiwavelength properties of several individual star-forming complexes (clumps). Using optical and UV colors, EW(H ), and population synthesis models we constrain the ages of the clumps and find 6 9 that the median clump age is 9 Myr. The clumps have masses ranging from a few ; 10 to 10 M .Ingeneral,the clumps in the tidal features have ages similar to those in the spiral region, but are less massive. The clumps provide 33%, 36%, and 70% of the far-UV, 8.0 m, and 24 m emission, respectively. The 8 and 24 m luminosities are used to es- timate the far-IR luminosities and the star formation rates of the clumps. The total clump star formation rate is 2:0 Æ À1 À1 0:8 M yr , while the entire Arp 82 system is forming stars at a rate of 4:9 Æ 2:0 M yr .Wefind,forthefirsttime, stars in the H i arc to the southeast of the NGC 2535 disk. -
Cancer and Gemini N E
Cancer and Gemini N E Arp 12 Arp 287 Arp 243 Arp 82 Arp 247 Arp 167 Arp 58 Arp 165 Arp 89 Arp ID RA Dec Mag Size Con U2K DSA 12 NGC 2608 08 35 17.0 +28 28 27 13.0b 2.2 x 1.3’ Cnc 75L 35R 58 UGC 4457 08 31 58.1 +19 12 48 14.2p 1.8 x 0.9’ Cnc 75L 47R PGC 23937 - - 82 NGC 2535 08 11 13.2 +25 12 22 13.3b 3.3 x 1.8’ Cnc 75L 35R NGC 2536 14.7b 0.9 x 0.7’ 89 NGC 2648 08 42 40.1 +14 17 10 12.7p 3.2 x 1.0’ Cnc 94L 47R MCG +2-22-6 15.4p 0.8 x 0.1’ 165 NGC 2418 07 36 37.9 +17 53 06 13.2p 1.8’ Gem 75R 48L 167 NGC 2672 08 49 22.3 +19 04 30 12.7b 2.9 x 2.7’ Cnc 74R 47R NGC 2673 14.1 1.2’ 243 NGC 2623 08 38 24.2 +25 45 01 14.0b 2.4 x 0.7’ Cnc 75L 35R 247 IC 2338 08 23 34.4 +21 20 43 14.7 0.7 x 0.5’ Cnc 75L 47R IC 2339 15.0b 0.7 x 0.5’ 287 NGC 2735 09 02 38.6 +25 56 06 14.1b 1.2 x 0.4’ Cnc 74R 35L NGC 2735A 16.8 0.2’ 212 Arp 12 Split armed spiral galaxy N Observing Notes: E 22" @ 377 and 458x NGC 2608 - Bright 5:2 elongated NGC 2604 patch with a much brighter bar running the full length of the halo.