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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. -
Axions and Other Similar Particles
1 91. Axions and Other Similar Particles 91. Axions and Other Similar Particles Revised October 2019 by A. Ringwald (DESY, Hamburg), L.J. Rosenberg (U. Washington) and G. Rybka (U. Washington). 91.1 Introduction In this section, we list coupling-strength and mass limits for light neutral scalar or pseudoscalar bosons that couple weakly to normal matter and radiation. Such bosons may arise from the spon- taneous breaking of a global U(1) symmetry, resulting in a massless Nambu-Goldstone (NG) boson. If there is a small explicit symmetry breaking, either already in the Lagrangian or due to quantum effects such as anomalies, the boson acquires a mass and is called a pseudo-NG boson. Typical examples are axions (A0)[1–4] and majorons [5], associated, respectively, with a spontaneously broken Peccei-Quinn and lepton-number symmetry. A common feature of these light bosons φ is that their coupling to Standard-Model particles is suppressed by the energy scale that characterizes the symmetry breaking, i.e., the decay constant f. The interaction Lagrangian is −1 µ L = f J ∂µ φ , (91.1) where J µ is the Noether current of the spontaneously broken global symmetry. If f is very large, these new particles interact very weakly. Detecting them would provide a window to physics far beyond what can be probed at accelerators. Axions are of particular interest because the Peccei-Quinn (PQ) mechanism remains perhaps the most credible scheme to preserve CP-symmetry in QCD. Moreover, the cold dark matter (CDM) of the universe may well consist of axions and they are searched for in dedicated experiments with a realistic chance of discovery. -
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, -
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. -
Memoria De Publicaciones 2017 Facultad De Ciencias Uam Memoria De Publicaciones De La Facultad De Ciencias 2017
MEMORIA DE PUBLICACIONES 2017 FACULTAD DE CIENCIAS UAM MEMORIA DE PUBLICACIONES DE LA FACULTAD DE CIENCIAS 2017 La Memoria de Publicaciones de la Facultad de Ciencias, como parte de la Memoria de Investigación, aspira a dar cuenta de los resultados de la investigación realizada a lo largo de 2017 por los profesores e investigadores de la Facultad. Ha sido realizada por la Biblioteca de Ciencias contando con las aportaciones facilitadas por los Departamentos y por el Decanato de la Facultad, en la persona de la Vicedecana de Investigación, a quienes agradecemos enormemente su aportación. Publicaciones en La Facultad ha generado un volumen de producción científica 2017 de 1.267 publicaciones 1.104 En 2017 se han publicado un total de 1.104 trabajos citables Trabajos Citables (entre artículos y revisiones) de los que 1.056 tienen Factor de Impacto calculado (96%) 73% La Facultad de Ciencias tiene un total de 807 trabajos Trabajos indexados en Q1, que supone el 73,10% del total de los Primer Cuartil – Q1 trabajos publicados, prácticamente igual que el año anterior. Algunos departamentos superan este porcentaje situándose entre el 85% y 96% 1 La Facultad de Ciencias tiene al único investigador de la UAM Highly Cited considerado como investigador altamente citado para el año Researchers 2017 en el área de Física, según los listados de Clarivate Analytics, elaborados a partir de la Web of Science. https://clarivate.com/hcr/researchers-list/archived-lists/ : es el profesor Francisco José García Vidal, del Departamento de Física Teórica de la Materia Condensada. Memoria de Publicaciones de la Facultad de Ciencias 2017 Página 2 de 146 ÍNDICE . -
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 -
Arxiv:1411.3063V2 [Astro-Ph.GA] 22 Nov 2014 Triker 1997; Rosenberg Et Al
Accepted to the Astrophysical Journal on November 11, 2014 Preprint typeset using LATEX style emulateapj v. 5/2/11 A HERO'S LITTLE HORSE: DISCOVERY OF A DISSOLVING STAR CLUSTER IN PEGASUS Dongwon Kim1 and Helmut Jerjen1 Research School of Astronomy and Astrophysics, The Australian National University, Mt Stromlo Observatory, via Cotter Rd, Weston, ACT 2611, Australia Accepted to the Astrophysical Journal on November 11, 2014 ABSTRACT We report the discovery of an ultra-faint stellar system in the constellation of Pegasus. This con- centration of stars was detected by applying our overdensity detection algorithm to the SDSS-DR10 and confirmed with deeper photometry from the Dark Energy Camera at the 4-m Blanco telescope. The best-fitting model isochrone indicates that this stellar system, Kim 1, features an old (12 Gyr) and metal-poor ([Fe/H]∼ −1:7) stellar population at a heliocentric distance of 19:8 ± 0:9 kpc. We measure a half-light radius of 6:9 ± 0:6 pc using a Plummer profile. The small physical size and the extremely low luminosity are comparable to the faintest known star clusters Segue 3, Koposov 1 & 2, and Mu~noz1. However, Kim 1 exhibits a lower star concentration and is lacking a well defined center. It also has an unusually high ellipticity and irregular outer isophotes, which suggests that we are seeing an intermediate mass star cluster being stripped by the Galactic tidal field. An extended search for evidence of an associated stellar stream within the 3 sqr deg DECam field remains inconclusive. The finding of Kim 1 is consistent with current overdensity detection limits and supports the hypothesis that there are still a substantial number of extreme low luminosity star clusters undetected in the wider Milky Way halo. -
Probing the Fundamental Nature of Dark Matter with the Large Synoptic Survey Telescope
Probing the Fundamental Nature of Dark Matter with the Large Synoptic Survey Telescope LSST Dark Matter Group arXiv:1902.01055v1 [astro-ph.CO] 4 Feb 2019 i Executive Summary More than 85 years after its astrophysical discovery, the fundamental nature of dark matter remains one of the foremost open questions in physics. Over the last several decades, an extensive experimental program has sought to determine the cosmological origin, fundamental constituents, and interaction mechanisms of dark matter. While the existing experimental program has largely focused on weakly-interacting massive particles, there is strong theoretical motivation to explore a broader set of dark matter candidates. As the high-energy physics program expands to “search for dark matter along every feasible avenue” (Ritz et al., 2014), it is essential to keep in mind that the only direct, empirical measurements of dark matter properties to date come from astrophysical and cosmological observations. The Large Synoptic Survey Telescope (LSST), a major joint experimental effort between NSF and DOE, provides a unique and impressive platform to study dark sector physics. LSST was originally envisioned as the “Dark Matter Telescope” (Tyson et al., 2001), though in recent years, studies of fundamental physics with LSST have been more focused on dark energy. Dark matter is an essential component of the standard ΛCDM model, and a detailed understanding of dark energy cannot be achieved without a detailed understanding of dark matter. In the precision era of LSST, studies of dark matter and dark energy are extremely complementary from both a technical and scientific standpoint. In addition, cosmology has consistently shown that it is impossible to separate the macroscopic distribution of dark matter from the microscopic physics governing dark matter. -
Eight Ultra-Faint Galaxy Candidates Discovered in Year Two of the Dark Energy Survey A
The Astrophysical Journal, 813:109 (20pp), 2015 November 10 doi:10.1088/0004-637X/813/2/109 © 2015. The American Astronomical Society. All rights reserved. EIGHT ULTRA-FAINT GALAXY CANDIDATES DISCOVERED IN YEAR TWO OF THE DARK ENERGY SURVEY A. Drlica-Wagner1, K. Bechtol2,3, E. S. Rykoff4,5, E. Luque6,7, A. Queiroz6,7,Y.-Y.Mao4,5,8, R. H. Wechsler4,5,8, J. D. Simon9, B. Santiago6,7, B. Yanny1, E. Balbinot7,10, S. Dodelson1,11, A. Fausti Neto7, D. J. James12,T.S.Li13, M. A. G. Maia7,14, J. L. Marshall13, A. Pieres6,7, K. Stringer13, A. R. Walker12, T. M. C. Abbott12, F. B. Abdalla15,16, S. Allam1, A. Benoit-Lévy15, G. M. Bernstein17, E. Bertin18,19, D. Brooks15, E. Buckley-Geer1, D. L. Burke4,5, A. Carnero Rosell7,14, M. Carrasco Kind20,21, J. Carretero22,23, M. Crocce22, L. N. da Costa7,14, S. Desai24,25, H. T. Diehl1, J. P. Dietrich24,25, P. Doel15,T.F.Eifler17,26, A. E. Evrard27,28, D. A. Finley1, B. Flaugher1, P. Fosalba22, J. Frieman1,11, E. Gaztanaga22, D. W. Gerdes28, D. Gruen29,30, R. A. Gruendl20,21, G. Gutierrez1, K. Honscheid31,32, K. Kuehn33, N. Kuropatkin1, O. Lahav15, P. Martini31,34, R. Miquel23,35, B. Nord1, R. Ogando7,14, A. A. Plazas26, K. Reil5, A. Roodman4,5, M. Sako17, E. Sanchez36, V. Scarpine1, M. Schubnell28, I. Sevilla-Noarbe20,36, R. C. Smith12, M. Soares-Santos1, F. Sobreira1,7, E. Suchyta31,32, M. E. C. Swanson21, G. Tarle28, D. Tucker1, V. Vikram37, W. Wester1, Y. Zhang28, and J. -
Arxiv:2104.09523V2 [Astro-Ph.GA] 20 Jul 2021
Accepted in The Astrophysical Journal Preprint typeset using LATEX style emulateapj v. 01/23/15 EVIDENCE OF A DWARF GALAXY STREAM POPULATING THE INNER MILKY WAY HALO Khyati Malhan1, Zhen Yuan2, Rodrigo A. Ibata2, Anke Arentsen2, Michele Bellazzini3, Nicolas F. Martin2,4 Accepted in The Astrophysical Journal ABSTRACT Stellar streams produced from dwarf galaxies provide direct evidence of the hierarchical formation of the Milky Way. Here, we present the first comprehensive study of the \LMS-1" stellar stream, that we detect by searching for wide streams in the Gaia EDR3 dataset using the STREAMFINDER algorithm. This stream was recently discovered by Yuan et al. (2020). We detect LMS-1 as a 60◦ long stream to the north of the Galactic bulge, at a distance of ∼ 20 kpc from the Sun, together with additional components that suggest that the overall stream is completely wrapped around the inner Galaxy. Using spectroscopic measurements from LAMOST, SDSS and APOGEE, we infer that the stream is very metal poor (h[Fe=H]i = −2:1) with a significant metallicity dispersion (σ[Fe=H] = 0:4), −1 and it possesses a large radial velocity dispersion (σv = 20 ± 4 km s ). These estimates together imply that LMS-1 is a dwarf galaxy stream. The orbit of LMS-1 is close to polar, with an inclination of 75◦ to the Galactic plane. Both the orbit and metallicity of LMS-1 are remarkably similar to the globular clusters NGC 5053, NGC 5024 and the stellar stream \Indus". These findings make LMS-1 an important contributor to the stellar population of the inner Milky Way halo.