Galaxy Formation & Evolution
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A New Milky Way Halo Star Cluster in the Southern Galactic Sky
The Astrophysical Journal, 767:101 (6pp), 2013 April 20 doi:10.1088/0004-637X/767/2/101 C 2013. The American Astronomical Society. All rights reserved. Printed in the U.S.A. A NEW MILKY WAY HALO STAR CLUSTER IN THE SOUTHERN GALACTIC SKY E. Balbinot1,2, B. X. Santiago1,2, L. da Costa2,3,M.A.G.Maia2,3,S.R.Majewski4, D. Nidever5, H. J. Rocha-Pinto2,6, D. Thomas7, R. H. Wechsler8,9, and B. Yanny10 1 Instituto de F´ısica, UFRGS, CP 15051, Porto Alegre, RS 91501-970, Brazil; [email protected] 2 Laboratorio´ Interinstitucional de e-Astronomia–LIneA, Rua Gal. Jose´ Cristino 77, Rio de Janeiro, RJ 20921-400, Brazil 3 Observatorio´ Nacional, Rua Gal. Jose´ Cristino 77, Rio de Janeiro, RJ 22460-040, Brazil 4 Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325, USA 5 Department of Astronomy, University of Michigan, Ann Arbor, MI 48109-1042, USA 6 Observatorio´ do Valongo, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 20080-090, Brazil 7 Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth, Hampshire PO1 2UP, UK 8 Kavli Institute for Particle Astrophysics and Cosmology, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA 9 Department of Physics, Stanford University, Stanford, CA 94305, USA 10 Fermi National Laboratory, P.O. Box 500, Batavia, IL 60510-5011, USA Received 2012 October 8; accepted 2013 February 28; published 2013 April 1 ABSTRACT We report on the discovery of a new Milky Way (MW) companion stellar system located at (αJ 2000,δJ 2000) = (22h10m43s.15, 14◦5658.8). -
Main Sequence Star Populations in the Virgo Overdensity Region
Draft version October 17, 2018 Preprint typeset using LATEX style emulateapj v. 5/2/11 MAIN SEQUENCE STAR POPULATIONS IN THE VIRGO OVERDENSITY REGION H. Jerjen1, G.S. Da Costa1, B. Willman2, P. Tisserand1, N. Arimoto3,4, S. Okamoto5, M. Mateo6, I. Saviane7, S. Walsh8, M. Geha9, A. Jordan´ 10,11, E. Olszewski12, M. Walker13, M. Zoccali10,11, P. Kroupa14 1Research School of Astronomy & Astrophysics, The Australian National University, Mt Stromlo Observatory, via Cotter Rd, Weston, ACT 2611, Australia 2Haverford College, Department of Astronomy, 370 Lancaster Avenue, Haverford, PA 19041, USA 3National Astronomical Observatory of Japan, Subaru Telescope, 650 North A'ohoku Place, Hilo, 96720 USA 4The Graduate University for Advanced Studies, Department of Astronomical Sciences, Osawa 2-21-1, Mitaka, Tokyo, Japan 5Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871, China 6Department of Astronomy, University of Michigan, Ann Arbor, MI, USA 7European Southern Observatory, Casilla 19001, Santiago 19, Chile 8Australian Astronomical Observatory, PO Box 915, North Ryde, NSW 1670, Australia 9Astronomy Department, Yale University, New Haven, CT 06520, USA 10Departamento de Astronom´ıay Astrof´ısica,Pontificia Universidad Cat´olicade Chile, 7820436 Macul, Santiago, Chile 11The Milky Way Millennium Nucleus, Av. Vicu~naMackenna 4860, 782-0436 Macul, Santiago, Chile 12Steward Observatory, The University of Arizona, Tucson, AZ, USA 13Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA and 14Argelander Institute for Astronomy, University of Bonn, Auf dem H¨ugel71,D-53121 Bonn, Germany Draft version October 17, 2018 ABSTRACT We present deep color-magnitude diagrams for two Subaru Suprime-Cam fields in the Virgo Stellar Stream(VSS)/Virgo Overdensity(VOD) and compare them to a field centred on the highest concen- tration of Sagittarius (Sgr) Tidal Stream stars in the leading arm, Branch A of the bifurcation. -
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. -
Chemo-Kinematics of the Milky Way from the SDSS-III MARVELS Survey
MNRAS 000,1–22 (2018) Preprint 6 October 2020 Compiled using MNRAS LATEX style file v3.0 Chemo-kinematics of the Milky Way from the SDSS-III MARVELS Survey Nolan Grieves,1¢ Jian Ge,1 Neil Thomas,2 Kevin Willis,1 Bo Ma,1 Diego Lorenzo-Oliveira,3,4 A. B. A. Queiroz,5,4 Luan Ghezzi,6 Cristina Chiappini,7,4 Friedrich Anders,7,4 Letícia Dutra-Ferreira,5,4 Gustavo F. Porto de Mello,8,4 Basílio X. Santiago,5,4 Luiz N. da Costa,6,4 Ricardo L. C. Ogando,6,4 E. F. del Peloso,4 Jonathan C. Tan,9,1 Donald P. Schneider,10,11 Joshua Pepper,12 Keivan G. Stassun,13 Bo Zhao,1 Dmitry Bizyaev,14,15 and Kaike Pan14 1Department of Astronomy, University of Florida, Gainesville, FL 32611, USA 2Department of Astronautical Engineering, United States Air Force Academy, CO 80840, USA 3Universidade de São Paulo, Departamento de Astronomia IAG/USP, Rua do Matão 1226, Cidade Universitária, São Paulo, SP 05508-900, Brazil 4Laboratório Interinstitucional de e-Astronomia-LIneA, Rua Gereral José Cristino 77, São Cristóvão, Rio de Janeiro, RJ 20921-400, Brazil 5Instituto de Física, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051,Porto Alegre, RS - 91501-970, Brazil 6Observatório Nacional, Rua General José Cristino 77, São Cristóvão, Rio de Janeiro, RJ 20921-400, Brazil 7Leibniz-Institut für Astrophysik Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany 8Observatório do Valongo, Universidade Federal do Rio de Janeiro, Ladeira do Pedro Antônio 43, Rio de Janeiro, RJ 20080-090, Brazil 9Department of Astronomy, University of Virginia, Charlottesville, VA 22904 10Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 11Center for Exoplanets and Habitable Worlds, The Pennsylvania State University, University Park, PA 16802 12Department of Physics, Lehigh University, 16 Memorial Drive East, Bethlehem, PA, 18015, USA 13Vanderbilt University, Physics & Astronomy Department, 6301 Stevenson Center Ln., Nashville, TN 37235 14Apache Point Observatory and New Mexico State University, P.O. -
The Detailed Properties of Leo V, Pisces II and Canes Venatici II
Haverford College Haverford Scholarship Faculty Publications Astronomy 2012 Tidal Signatures in the Faintest Milky Way Satellites: The Detailed Properties of Leo V, Pisces II and Canes Venatici II David J. Sand Jay Strader Beth Willman Haverford College Dennis Zaritsky Follow this and additional works at: https://scholarship.haverford.edu/astronomy_facpubs Repository Citation Sand, David J., Jay Strader, Beth Willman, Dennis Zaritsky, Brian Mcleod, Nelson Caldwell, Anil Seth, and Edward Olszewski. "Tidal Signatures In The Faintest Milky Way Satellites: The Detailed Properties Of Leo V, Pisces Ii, And Canes Venatici Ii." The Astrophysical Journal 756.1 (2012): 79. Print. This Journal Article is brought to you for free and open access by the Astronomy at Haverford Scholarship. It has been accepted for inclusion in Faculty Publications by an authorized administrator of Haverford Scholarship. For more information, please contact [email protected]. The Astrophysical Journal, 756:79 (14pp), 2012 September 1 doi:10.1088/0004-637X/756/1/79 C 2012. The American Astronomical Society. All rights reserved. Printed in the U.S.A. TIDAL SIGNATURES IN THE FAINTEST MILKY WAY SATELLITES: THE DETAILED PROPERTIES OF LEO V, PISCES II, AND CANES VENATICI II∗ David J. Sand1,2,7, Jay Strader3, Beth Willman4, Dennis Zaritsky5, Brian McLeod3, Nelson Caldwell3, Anil Seth6, and Edward Olszewski5 1 Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Santa Barbara, CA 93117, USA; [email protected] 2 Department of Physics, Broida Hall, -
Wyn Evans Institute of Astronomy, Cambridge
DARK MATTER SUBSTRUCTURES IN THE NEARBY UNIVERSE Wyn Evans Institute of Astronomy, Cambridge Monday, 16 July 2012 DARK MATTER 1. The dwarf spheroidals 2. The ultra-faints 3. The clouds & streams 4. The unknown Monday, 16 July 2012 DWARF SPHEROIDALS Image (35’ by 35’) of the Sculptor dwarf spheroidal taken with the NOAO CTIO 4 m telescope. Monday, 16 July 2012 DWARF SPHEROIDALS Surrounding the Milky Way are 9 classical dwarf spheroidal galaxies (Scu, For, Leo I, Leo II, UMi, Dra, Car, Sex, Sgr). These contain intermediate age to old stellar populations and no gas. They have velocity dispersions ∼ 8-10 km/s, half-light radius ∼ 200-300 pc, and absolute magnitudes MV brighter than -8. They are all highly dark matter dominated, and are natural targets for indirect detection experiments. What are their dark matter profiles? Are they cusped or cored? Monday, 16 July 2012 DWARF SPHEROIDALS Radial velocity surveys with multi-object spectrographs have now provided datasets of thousands of velocities for the giants stars. Early hopes that the photometry and line of sight velocity dispersion profile could be used to constrain the dark halo give way to pessimism. Most early modelers used the spherical Jeans equations to deduce dark matter properties at the center. Monday, 16 July 2012 JEANS EQUATIONS • The spherical Jeans equation is dangerous! If the light profile is cored (Plummer), then assuming isotropy gives a cored dark matter density. If the light profile is cusped (exponential), then so is the dark halo (An & Evans 2009). • The degeneracies in the Jeans equations are also illustrated by Walker et al. -
Spatial Distribution of Galactic Globular Clusters: Distance Uncertainties and Dynamical Effects
Juliana Crestani Ribeiro de Souza Spatial Distribution of Galactic Globular Clusters: Distance Uncertainties and Dynamical Effects Porto Alegre 2017 Juliana Crestani Ribeiro de Souza Spatial Distribution of Galactic Globular Clusters: Distance Uncertainties and Dynamical Effects Dissertação elaborada sob orientação do Prof. Dr. Eduardo Luis Damiani Bica, co- orientação do Prof. Dr. Charles José Bon- ato e apresentada ao Instituto de Física da Universidade Federal do Rio Grande do Sul em preenchimento do requisito par- cial para obtenção do título de Mestre em Física. Porto Alegre 2017 Acknowledgements To my parents, who supported me and made this possible, in a time and place where being in a university was just a distant dream. To my dearest friends Elisabeth, Robert, Augusto, and Natália - who so many times helped me go from "I give up" to "I’ll try once more". To my cats Kira, Fen, and Demi - who lazily join me in bed at the end of the day, and make everything worthwhile. "But, first of all, it will be necessary to explain what is our idea of a cluster of stars, and by what means we have obtained it. For an instance, I shall take the phenomenon which presents itself in many clusters: It is that of a number of lucid spots, of equal lustre, scattered over a circular space, in such a manner as to appear gradually more compressed towards the middle; and which compression, in the clusters to which I allude, is generally carried so far, as, by imperceptible degrees, to end in a luminous center, of a resolvable blaze of light." William Herschel, 1789 Abstract We provide a sample of 170 Galactic Globular Clusters (GCs) and analyse its spatial distribution properties. -
The Saga of M81: Global View of a Massive Stellar Halo in Formation
Draft version October 27, 2020 Typeset using LATEX twocolumn style in AASTeX63 The Saga of M81: Global View of a Massive Stellar Halo in Formation Adam Smercina ,1, 2 Eric F. Bell ,1 Paul A. Price,3 Colin T. Slater ,2 Richard D'Souza,1, 4 Jeremy Bailin ,5 Roelof S. de Jong ,6 In Sung Jang ,6 Antonela Monachesi ,7, 8 and David Nidever 9, 10 1Department of Astronomy, University of Michigan, Ann Arbor, MI 48109, USA 2Astronomy Department, University of Washington, Box 351580, Seattle, WA 98195-1580, USA 3Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA 4Vatican Observatory, Specola Vaticana, V-00120, Vatican City State 5Department of Physics and Astronomy, University of Alabama, Box 870324, Tuscaloosa, AL 35487-0324, USA 6Leibniz-Institut f¨urAstrophysik Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany 7Instituto de Investigaci´onMultidisciplinar en Ciencia y Tecnolog´ıa,Universidad de La Serena, Ra´ulBitr´an1305, La Serena, Chile 8Departamento de F´ısica y Astronom´ıa,Universidad de La Serena, Av. Juan Cisternas 1200 N, La Serena, Chile 9Department of Physics, Montana State University, P.O. Box 173840, Bozeman, MT 59717-3840 10National Optical Astronomy Observatory, 950 North Cherry Ave, Tucson, AZ 85719 (Received 31 October, 2019; Revised 31 August, 2020; Accepted 23 October, 2020) Submitted to The Astrophysical Journal ABSTRACT Recent work has shown that Milky Way-mass galaxies display an incredible range of stellar halo properties, yet the origin of this diversity is unclear. The nearby galaxy M81 | currently interacting with M82 and NGC 3077 | sheds unique light on this problem. -
Galactic Archaeology. the Dwarfs That Survived and Perished
Galactic Archaeology. The dwarfs that survived and perished Vasily Belokurova,∗ aInstitute of Astronomy, Cambridge Abstract From the archaeological point of view, the local dwarf galaxies are unique objects in which the imprint of the conditions that shaped the early structure formation can be studied today at high resolution. Over the last decade, this new window into the high redshift Universe has started to be exploited using deep wide-field imaging, high resolution spectroscopy and cutting edge N- body and hydro-dynamical simulations. We review the recent advances in the observational studies of the Milky Way dwarf galaxies, with the aim to understand the properties of the population as a whole and to assist an objective comparison between the models and the data. Keywords: Galaxies: kinematics and dynamics, Galaxies: dwarf, dark matter, Local Group, Galaxies: stellar content. 1. Introduction The prehistoric stars whose formation epochs lie beyond the redshift ac- cessible by the Hubble Ultra Deep Field, have been found en masse in little satellites around the Milky Way. Other less fortunate dwarf galaxies have been pulled apart by gravity to furnish the diffuse Galactic halo. These re- cently uncovered relics of the ancient dwarf galaxy population may play a arXiv:1307.0041v2 [astro-ph.GA] 15 Jul 2013 vital role in the pursuit of reconstructing the formation of the Galaxy. Its path from the distant pre-reionisation era, through the most active growth ∗Corresponding author Email address: [email protected] (Vasily Belokurov) Preprint submitted to New Astronomy Reviews July 16, 2013 periods to the present day, can be gleaned by studying the chemical compo- sition and the phase-space density distribution of these halo denizens. -
Formation of Disc Galaxies from Cosmological Simulations: Galactic Outflows and Chemical Evolution
Scuola Internazionale Superiore di Studi Avanzati - Trieste Formation of disc galaxies from cosmological simulations: galactic outflows and chemical evolution Author: Milena Valentini Supervisors: Prof. Stefano Borgani, Prof. Alessandro Bressan, Dr. Giuseppe Murante International School for Advanced Studies SISSA/ISAS A thesis submitted in fulfilment of the requirements for the degree of Doctor Philosophiae in ASTROPHYSICS and COSMOLOGY October 2018 SISSA - Via Bonomea 265 - 34136 TRIESTE - ITALY To Nicola Abstract In this Thesis, I study the formation of late-type galaxies and the role that feedback from stars and supermassive black holes (SMBHs) plays in galaxy evolution across cosmic time. By carrying out cosmological hydrodynamical simulations, I investigate how different processes, such as the cosmological gas accretion from the large scale environment, star formation and chemical enrichment, stellar and AGN (Active Galactic Nucleus) feedback, affect the early stages of forming galaxies and contribute to determine their present-day properties. Driven by the challenging task of simulating late-type galaxies with a limited bulge and a dominant disc in a cosmological context, I study the impact of galactic outflow modelling on the formation and evolution of a disc galaxy. I find that galactic outflows regulate the timing of gas accretion and determine the star formation history of the forming galaxy. Also, I quantify the strong interplay between the adopted hydrodynamical scheme and the sub-resolution model describing star formation and stellar feedback. Throughout this Thesis, I devote particular emphasis to connect chemical evolution and gas dynamics, in order to interpret observations of metal abundance in the interstellar medium (ISM) and circumgalactic medium (CGM). -
Eight New Milky Way Companions Discovered in FirstYear Dark Energy Survey Data
Eight new Milky Way companions discovered in first-year Dark Energy Survey Data Article (Published Version) Romer, Kathy and The DES Collaboration, et al (2015) Eight new Milky Way companions discovered in first-year Dark Energy Survey Data. Astrophysical Journal, 807 (1). ISSN 0004- 637X This version is available from Sussex Research Online: http://sro.sussex.ac.uk/id/eprint/61756/ This document is made available in accordance with publisher policies and may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher’s version. Please see the URL above for details on accessing the published version. Copyright and reuse: Sussex Research Online is a digital repository of the research output of the University. Copyright and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable, the material made available in SRO has been checked for eligibility before being made available. Copies of full text items generally can be reproduced, displayed or performed and given to third parties in any format or medium for personal research or study, educational, or not-for-profit purposes without prior permission or charge, provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. http://sro.sussex.ac.uk The Astrophysical Journal, 807:50 (16pp), 2015 July 1 doi:10.1088/0004-637X/807/1/50 © 2015. -
What Is an Ultra-Faint Galaxy?
What is an ultra-faint Galaxy? UCSB KITP Feb 16 2012 Beth Willman (Haverford College) ~ 1/10 Milky Way luminosity Large Magellanic Cloud, MV = -18 image credit: Yuri Beletsky (ESO) and APOD NGC 205, MV = -16.4 ~ 1/40 Milky Way luminosity image credit: www.noao.edu Image credit: David W. Hogg, Michael R. Blanton, and the Sloan Digital Sky Survey Collaboration ~ 1/300 Milky Way luminosity MV = -14.2 Image credit: David W. Hogg, Michael R. Blanton, and the Sloan Digital Sky Survey Collaboration ~ 1/2700 Milky Way luminosity MV = -11.9 Image credit: David W. Hogg, Michael R. Blanton, and the Sloan Digital Sky Survey Collaboration ~ 1/14,000 Milky Way luminosity MV = -10.1 ~ 1/40,000 Milky Way luminosity ~ 1/1,000,000 Milky Way luminosity Ursa Major 1 Finding Invisible Galaxies bright faint blue red Willman et al 2002, Walsh, Willman & Jerjen 2009; see also e.g. Koposov et al 2008, Belokurov et al. Finding Invisible Galaxies Red, bright, cool bright Blue, hot, bright V-band apparent brightness V-band faint Red, faint, cool blue red From ARAA, V26, 1988 Willman et al 2002, Walsh, Willman & Jerjen 2009; see also e.g. Koposov et al 2008, Belokurov et al. Finding Invisible Galaxies Ursa Major I dwarf 1/1,000,000 MW luminosity Willman et al 2005 ~ 1/1,000,000 Milky Way luminosity Ursa Major 1 CMD of Ursa Major I Okamoto et al 2008 Distribution of the Milky Wayʼs dwarfs -14 Milky Way dwarfs 107 -12 -10 classical dwarfs V -8 5 10 Sun M L -6 ultra-faint dwarfs Canes Venatici II -4 Leo V Pisces II Willman I 1000 -2 Segue I 0 50 100 150 200 250 300