A Synoptic Map of Halo Substructures from the Pan-STARRS1 3\Pi\Survey
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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). -
Arxiv:Astro-Ph/0609104V2 31 Jan 2007
Draft version July 23, 2018 A Preprint typeset using LTEX style emulateapj v. 08/22/09 THE VIRGO STELLAR OVER-DENSITY: MAPPING THE INFALL OF THE SAGITTARIUS TIDAL STREAM ONTO THE MILKY WAY DISK David Mart´ınez-Delgado1,2, Jorge Penarrubia˜ 3,4, Mario Juric´5,6, Emilio J. Alfaro2, Zeljko Ivezic´5 Draft version July 23, 2018 ABSTRACT The recently discovered Virgo stellar over-density, which expands over 1000deg2 perpendicularly to the Galactic disk plane (7<Z < 15 kpc, R 7 kpc), is the largest∼ clump of tidal debris ever detected in the outer halo and is likely related with∼ the accretion of a nearby dwarf galaxy by the Milky Way. We carry out N-body simulations of the Sagittarius stream to show that this giant stellar over-density is a confirmation of theoretical model predictions for the leading tail of the Sagittarius stream to cross the Milky Way plane in the Solar neighborhood. Radial velocity measurements are needed to confirm this association and to further constrain the shape of the Milky Way dark matter halo through a new generation of theoretical models. If the identification of Virgo over-density and the Sagittarius leading arm is correct, we predict highly negative radial velocities for the stars of Virgo over-density. The detection of this new portion of the Sagittarius tidal stream would represent an excellent target for the on-going and future kinematic surveys and for dark matter direct detection experiments in the proximity of the Sun. Subject headings: galaxies: individual (Sagittarius) — galaxies:interactions—Galaxy: structure — Galaxy: halo 1. -
A Beast with Four Tails 30 November 2011
A beast with four tails 30 November 2011 An artist's impression of the four tails of the Sagittarius Dwarf Galaxy (the orange clump on the left of the image) orbiting the Milky Way. The bright yellow circle to the right of the galaxy's center is our Sun (not to scale). The Sagittarius dwarf galaxy is on the other side of the galaxy from us, but we can see its tidal tails of stars (white in this Barred Spiral Milky Way. Illustration Credit: R. Hurt image) stretching across the sky as they wrap around our (SSC), JPL-Caltech, NASA galaxy. Credit: Credit: Amanda Smith, Institute of Astronomy, University of Cambridge (PhysOrg.com) -- The Milky Way galaxy continues to devour its small neighbouring dwarf galaxies The Sagittarius dwarf galaxy used to be one of the and the evidence is spread out across the sky. brightest of the Milky Way satellites. Its disrupted remnant now lies on the other side of the Galaxy, A team of astronomers led by Sergey Koposov and breaking up as it is crushed and stretched by huge Vasily Belokurov of Cambridge University recently tidal forces. It is so small that it has lost half of its discovered two streams of stars in the Southern stars and all its gas over the last billion years. Galactic hemisphere that were torn off the Sagittarius dwarf galaxy. This discovery came from Before SDSS-III, Sagittarius was known to have analysing data from the latest Sloan Digital Sky two tails, one in front of and one behind the Survey (SDSS-III) and was announced in a paper remnant. -
University of Groningen the Sagittarius Stream with Gaia Data
University of Groningen The Sagittarius stream with Gaia data Antoja, T.; Ramos, P.; Mateu, C.; Helmi, A.; Castro-Ginard, A.; Anders, F.; Jordi, C.; Carballo- Bello, J. A.; Balbinot, E.; Carrasco, J. M. IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite from it. Please check the document version below. Document Version Publisher's PDF, also known as Version of record Publication date: 2020 Link to publication in University of Groningen/UMCG research database Citation for published version (APA): Antoja, T., Ramos, P., Mateu, C., Helmi, A., Castro-Ginard, A., Anders, F., Jordi, C., Carballo-Bello, J. A., Balbinot, E., & Carrasco, J. M. (2020). The Sagittarius stream with Gaia data. Paper presented at EA XIV.0 Reunión Científica , . https://ui.adsabs.harvard.edu/abs/2020sea..confE.117A Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons). The publication may also be distributed here under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license. More information can be found on the University of Groningen website: https://www.rug.nl/library/open-access/self-archiving-pure/taverne- amendment. Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. -
A Complete Spectroscopic Survey of the Milky Way Satellite Segue 1: the Darkest Galaxy
Haverford College Haverford Scholarship Faculty Publications Astronomy 2011 A Complete Spectroscopic Survey of the Milky Way Satellite Segue 1: The Darkest Galaxy Joshua D. Simon Marla Geha Quinn E. Minor Beth Willman Haverford College Follow this and additional works at: https://scholarship.haverford.edu/astronomy_facpubs Repository Citation A Complete Spectroscopic Survey of the Milky Way satellite Segue 1: Dark matter content, stellar membership and binary properties from a Bayesian analysis - Martinez, Gregory D. et al. Astrophys.J. 738 (2011) 55 arXiv:1008.4585 [astro-ph.GA] 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, 733:46 (20pp), 2011 May 20 doi:10.1088/0004-637X/733/1/46 C 2011. The American Astronomical Society. All rights reserved. Printed in the U.S.A. A COMPLETE SPECTROSCOPIC SURVEY OF THE MILKY WAY SATELLITE SEGUE 1: THE DARKEST GALAXY∗ Joshua D. Simon1, Marla Geha2, Quinn E. Minor3, Gregory D. Martinez3, Evan N. Kirby4,8, James S. Bullock3, Manoj Kaplinghat3, Louis E. Strigari5,8, Beth Willman6, Philip I. Choi7, Erik J. Tollerud3, and Joe Wolf3 1 Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101, USA; [email protected] 2 Astronomy Department, Yale University, New Haven, CT 06520, USA; [email protected] -
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. -
Astro-Ph.GA] 28 May 2015
SLAC-PUB-16746 Eight New Milky Way Companions Discovered in First-Year Dark Energy Survey Data K. Bechtol1;y, A. Drlica-Wagner2;y, E. Balbinot3;4, A. Pieres5;4, J. D. Simon6, B. Yanny2, B. Santiago5;4, R. H. Wechsler7;8;11, J. Frieman2;1, A. R. Walker9, P. Williams1, E. Rozo10;11, E. S. Rykoff11, A. Queiroz5;4, E. Luque5;4, A. Benoit-L´evy12, D. Tucker2, I. Sevilla13;14, R. A. Gruendl15;13, L. N. da Costa16;4, A. Fausti Neto4, M. A. G. Maia4;16, T. Abbott9, S. Allam17;2, R. Armstrong18, A. H. Bauer19, G. M. Bernstein18, R. A. Bernstein6, E. Bertin20;21, D. Brooks12, E. Buckley-Geer2, D. L. Burke11, A. Carnero Rosell4;16, F. J. Castander19, R. Covarrubias15, C. B. D'Andrea22, D. L. DePoy23, S. Desai24;25, H. T. Diehl2, T. F. Eifler26;18, J. Estrada2, A. E. Evrard27, E. Fernandez28;39, D. A. Finley2, B. Flaugher2, E. Gaztanaga19, D. Gerdes27, L. Girardi16, M. Gladders29;1, D. Gruen30;31, G. Gutierrez2, J. Hao2, K. Honscheid32;33, B. Jain18, D. James9, S. Kent2, R. Kron1, K. Kuehn34;35, N. Kuropatkin2, O. Lahav12, T. S. Li23, H. Lin2, M. Makler36, M. March18, J. Marshall23, P. Martini33;37, K. W. Merritt2, C. Miller27;38, R. Miquel28;39, J. Mohr24, E. Neilsen2, R. Nichol22, B. Nord2, R. Ogando4;16, J. Peoples2, D. Petravick15, A. A. Plazas40;26, A. K. Romer41, A. Roodman7;11, M. Sako18, E. Sanchez14, V. Scarpine2, M. Schubnell27, R. C. Smith9, M. Soares-Santos2, F. Sobreira2;4, E. Suchyta32;33, M. E. C. Swanson15, G. -
Arxiv:1402.4519V1 [Astro-Ph.GA] 18 Feb 2014 Rdcsasgicn Hs Hf Nteepce Nulmod Annual Expected Particles
Structure and Dynamics of Disk Galaxies ASP Conference Series, Vol. 480 Marc S. Seigar and Patrick Treuhardt c 2013 Astronomical Society of the Pacific The Sagittarius Impact on Light and Dark Structure in the Milky Way Chris W. Purcell1 1Department of Physics and Astronomy, West Virginia University Abstract. It is increasingly apparent that common merger events play a large role in the evolution of disk galaxies at all cosmic times, from the wet accretion of gas-filled dwarf galaxies during the era of peak star formation, to the collisions between large, dynamically-advanced spiral galaxies and their dry companion satellites, a type of in- teraction that continues to influence disk structure into the present day. We also live in a large spiral galaxy currently undergoing a series of impacts from an infalling, disrupt- ing dwarf galaxy. As next-generation astrometry proposes to place our understanding of the Milky Way spiral structure on a much firmer footing, we analyze high-resolution numerical models of this disk-satellite interaction in order to assess the dynamical re- sponse of our home Galaxy to the Sagittarius dwarf impact, and possible implications for experiments hoping to directly detect dark matter passing through the Earth. Throughout this proceeding, we discuss the results initially presented in Purcell et al. (2011) and Purcell et al. (2012), in which we perform high-resolution N-body experi- ments involving a dwarf galaxy model with parameters similar to those indicated by observational constraints on the Sagittarius (Sgr) progenitor (Niederste-Ostholt et al. 2010), as it is accreted into a Milky Way-like system that is initially a stellar disk in equilibrium with a host halo. -
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. -
Rings and Radial Waves in the Disk of the Milky Way Xu, Newberg, Carlin, Liu, Deng, Li, Schönrich & Yanny, Apj, in Press, 2015
Dana Berry Rings and Radial Waves in the Disk of the Milky Way Xu, Newberg, Carlin, Liu, Deng, Li, Schönrich & Yanny, ApJ, in press, 2015 We identify an asymmetry in disk stars that oscillates Xu Yan from the north to the south to the north to the south NAOC, Beijing across the Galactic plane in the anticenter direction. Newberg et al. 2002 ? Monoceros Ring Vivas overdensity, or Virgo Stellar Stream Hercules-Aquila Cloud Stellar Spheroid Sagittarius Dwarf Tidal Stream Monoceros Monoceros (l,b)=(200°, -24°) (l, b) = (123°, -19°) Newberg et al. (2002), Figure 15 Ibata et al. (2003), Figure 6 The early papers differed on the identification of Monoceros in the south, leading to a decade of confusion in the literature. Newberg et al. 2002 Monoceros stream, Stream in the Galactic Plane, ? Galactic Anticenter Stellar Stream, Vivas overdensity, or Canis Major Stream, Virgo Stellar Stream Argo Navis Stream Hercules-Aquila Cloud Stellar Spheroid Sagittarius Dwarf Tidal Stream The SDSS also took imaging (and spectroscopic) data along 2.5°- wide stripes at constant Galactic longitude. These stripes cross the Galactic plane. The SDSS also took imaging (and spectroscopic) data along 2.5°- wide stripes at constant Galactic longitude. These stripes cross the Galactic plane. Counts of Stars with 0.4 < (g −r) < 0.5 Direction of 0 reddening vector Getting the reddening wrong does not change the result. The difference in counts is huge – like a factor of two. Isochrone Fitting (l,b)=(178◦, 15◦) (l,b)=(203◦,−25◦) Isochrones were fit to the north near ([Fe/H]=-0.5), south middle ([Fe/H]=-0.88), Monoceros Ring (M5), and TriAnd Ring (M5), using empirical isochrones from An et al. -
Proper Motions in Kapteyn Selected Area 103: a Preliminary Orbit for The
Proper Motions in Kapteyn Selected Area 103: A Preliminary Orbit for the Virgo Stellar Stream Dana I. Casetti-Dinescu1,2,3, Terrence M. Girard1, Steven R. Majewski4, A. Katherina Vivas5, Ronald Wilhelm6, Jeffrey L. Carlin4, Timothy C. Beers7, and William F. van Altena1 ABSTRACT We present absolute proper motions in Kapteyn Selected Area (SA) 103. This field is located 7◦ west of the center of the Virgo Stellar Stream (VSS, Duffau et al. 2006), and has a well-defined main sequence representing the stream. In SA 103, we identify one RR Lyrae star as a member of the VSS, according to its metallicity, radial velocity, and distance. VSS candidate turnoff and subgiant stars have proper motions consistent with that of the RR Lyrae star. The 3D velocity data imply an orbit with a pericenter of ∼ 11 kpc and an apocenter of ∼ 90 kpc. Thus, the VSS comprises tidal debris found near the pericenter of a highly destructive orbit. Examining the six globular clusters at distances larger than 50 kpc from the Galactic center, and the proposed orbit of the VSS, we find one tentative association, NGC 2419. We speculate that NGC 2419 is possibly the nucleus of a disrupted system of which the VSS is a part. Subject headings: Galaxy: structure — Galaxy: kinematics and dynamics — Galaxy: halo 1Astronomy Department, Yale University, P.O. Box 208101, New Haven, CT 06520-8101, USA 2 arXiv:0907.1249v1 [astro-ph.GA] 7 Jul 2009 Astronomy Department, Van Vleck Observatory, Wesleyan University, Middletown, CT 06459, USA 3Astronomical Institute of the Romanian Academy, Str. Cutitul de Argint 5, RO-75212, Bucharest 28, Romania 4Department of Astronomy, University of Virginia, P.O Box 400325, Charlottesville, VA 22904-4325 5Centro de Investigaciones de Astronomia (CIDA), Apartado Postal 264, M´erida, 5101-A, Venezuela 6Department of Physics, Texas Tech University, Lubbock, TX 79409, USA 7Department of Physics and Astronomy, CSCE: Center for the Study of Cosmic Evolution, and JINA: Joint Institution for Nuclear Astrophysics, Michigan State University, E. -
The Milky Way and Other Spiral Galaxies F.Hammera, M
EPJ Web of Conferences 19, 01004 (2012) DOI: 10.1051/epjconf/20121901004 C Owned by the authors, published by EDP Sciences, 2012 The Milky Way and other spiral galaxies F.Hammera, M. Puech, H. Flores, Y.B. Yang, J.L. Wang, and S. Fouquet GEPI, Observatoire de Paris, CNRS, 5 place Jules Janssen, 92195 Meudon, France Abstract. Cosmologists have often considered the Milky Way as a typical spiral galaxy, and its properties have considerably influenced the current scheme of galaxy formation. Here we compare the general properties of the Milky Way disk and halo with those of galaxies selected from the SDSS. Assuming the recent measurements of its circular velocity results in the Milky Way being offset by ∼2 from the fundamental scaling relations. On the basis of their location in the (MK , Rd , Vflat) volume, the fraction of SDSS spirals like the MilkyWay is only 1.2% in sharp contrast with M31, which appears to be quite typical. Comparison of the Milky Way with M31 and with other spirals is also discussed to investigate whether or not there is a fundamental discrepancy between their mass assembly histories. Possibly the Milky Way is one of the very few local galaxies that could be a direct descendant of very distant, z = 2-3 galaxies, thanks to its quiescent history since thick disk formation. 1. INTRODUCTION The Milky Way is one of the 72% of massive1 galaxies that are disk dominated. How large disks formed in massive spirals? The question is still not fully answered. Disks are supported by their angular momentum that may be acquired by early interactions in the framework of the tidal torque (TT) theory [1, 2].