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Antlia B: A Faint Dwarf Galaxy Member of the NGC 3109 Association

Sand, D. J. and Spekkens, K. and Crnojević, D. and Hargis, J. R. and Willman, B. and Strader, J. and Grillmair, C. J. (2015) Antlia B: A Faint Dwarf Galaxy Member of the NGC 3109 Association. Astrophysical Journal Letters, 812 (1). Art. No. L13. ISSN 2041-8205.

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We report the discovery of Antlia B, a faint dwarf galaxy at a projected distance of ~72 kpc from NGC 3109 (M_V ~ -15 mag), the primary galaxy of the NGC 3109 dwarf association at the edge of the Local Group. The tip of the red giant branch distance to Antlia B is D = 1.29 ± 0.10 Mpc, which is consistent with the distance to NGC 3109. A qualitative analysis indicates the new dwarf's stellar population has both an old, metal-poor red giant branch (≳10 Gyr, [Fe/H] ~ −2), and a younger blue population with an age of ~200–400 Myr, analogous to the original Antlia dwarf, another likely satellite of NGC 3109. Antlia B has H i gas at a velocity of v_(helio,HI) = 376 km s^(−1), confirming the association with NGC 3109 (v_(helio) = 403 km s^(−1)). The H i gas mass (M_(H i) = 2.8 ± 0.2 × 10^5 M_☉), stellar luminosity (M_V = −9.7 ± 0.6 mag) and half light radius (r_h = 273 ± 29 pc) are all consistent with the properties of dwarf irregular and dwarf spheroidal galaxies in the Local Volume, and is most similar to the Leo P dwarf galaxy. The discovery of Antlia B is the initial result from a Dark Energy Camera survey for halo substructure and faint dwarf companions to NGC 3109 with the goal of comparing observed substructure with expectations from the Λ+Cold Dark Matter model in the sub-Milky Way regime.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Sand, D. J.0000-0003-4102-380X
Spekkens, K.0000-0002-0956-7949
Crnojević, D.0000-0002-1763-4128
Hargis, J. R.0000-0002-8722-9806
Willman, B.0000-0003-2892-9906
Strader, J.0000-0002-1468-9668
Grillmair, C. J.0000-0003-4072-169X
Additional Information:© 2015. The American Astronomical Society. Received 2015 August 6; accepted 2015 September 14; published 2015 October 9. D.J.S. acknowledges support from NSF grant AST-1412504. K.S. acknowledges support from the Natural Sciences and Engineering Research Council of Canada. B.W. and J.H. were supported by an NSF Faculty Early Career Development (CAREER) award (AST-1151462). The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. This work was supported in part by National Science Foundation grant No. PHYS-1066293 and the Aspen Center for Physics. This project used data obtained with the Dark Energy Camera, which was constructed by the Dark Energy Survey collaboration. Funding for the DES Projects has been provided by the DOE and NSF(USA), MISE(Spain), STFC(UK), HEFCE(UK). NCSA(UIUC), KICP(U. Chicago), CCAPP(Ohio State), MIFPA(Texas A&M), CNPQ, FAPERJ, FINEP (Brazil), MINECO(Spain), DFG(Germany) and the collaborating institutions in the DES, which are Argonne Lab, UC Santa Cruz, University of Cambridge, CIEMAT-Madrid, University of Chicago, University College London, DES-Brazil Consortium, University of Edinburgh, ETH Zurich, Fermilab, University of Illinois, ICE (IEEC-CSIC), IFAE Barcelona, Lawrence Berkeley Lab, LMU Munchen and the associated Excellence Cluster Universe, University of Michigan, NOAO, University of Nottingham, Ohio State University, University of Pennsylvania, University of Portsmouth, SLAC National Lab, Stanford University, University of Sussex, and Texas A&M University.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
Aspen Center for PhysicsUNSPECIFIED
Department of Energy (DOE)UNSPECIFIED
Science and Technology Facilities Council (STFC)UNSPECIFIED
Higher Education Funding Council for EnglandUNSPECIFIED
National Center for Supercomputing Applications (NCSA)UNSPECIFIED
Kavli Institute for Cosmological PhysicsUNSPECIFIED
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)UNSPECIFIED
Ministerio de Economía y Competitividad (MINECO)UNSPECIFIED
Deutsche Forschungsgemeinschaft (DFG)UNSPECIFIED
Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)UNSPECIFIED
Financiadora de Estudos e Projetos (FINEP)UNSPECIFIED
Subject Keywords:dark matter; galaxies: dwarf
Issue or Number:1
Record Number:CaltechAUTHORS:20151207-092435621
Persistent URL:
Official Citation:D. J. Sand et al 2015 ApJ 812 L13
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:62639
Deposited By: Ruth Sustaita
Deposited On:08 Dec 2015 17:42
Last Modified:09 Mar 2020 13:18

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