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The most dark-matter-dominated galaxies : predicted gamma-ray signals from the faintest milky way dwarfs

Strigari, Louis E. and Koushiappas, Savvas M. and Bullock, James S. and Kaplinghat, Manoj and Simon, Joshua D. and Geha, Marla and Willman, Beth (2008) The most dark-matter-dominated galaxies : predicted gamma-ray signals from the faintest milky way dwarfs. Astrophysical Journal, 678 (2). pp. 614-620. ISSN 0004-637X.

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We use kinematic data from three new nearby, extremely low luminosity Milky Way dwarf galaxies (Ursa Major II, Willman 1, and Coma Berenices) to constrain the properties of their dark matter halos, and from these we make predictions for the γ-ray flux from annihilation of dark matter particles in these halos. We show that these ~10^3 L⊙ dwarfs are the most dark-matter-dominated galaxies known, with total masses within 100 pc that are in excess of 10^6 M⊙. Coupled with their relative proximity, their large masses imply that they should have mean γ-ray fluxes that are comparable to or greater than those of any other known satellite galaxy of the Milky Way. Our results are robust to both variations of the inner slope of the density profile and the effect of tidal interactions. The fluxes could be boosted by up to 2 orders of magnitude if we include the density enhancements caused by surviving dark matter substructure.

Item Type:Article
Related URLs:
URLURL TypeDescription
Bullock, James S.0000-0003-4298-5082
Geha, Marla0000-0002-7007-9725
Willman, Beth0000-0003-2892-9906
Additional Information:© 2008 The American Astronomical Society. Received 2007 October 12; accepted 2008 January 7. We are grateful to Simon White for many useful discussions on likelihood functions for dwarf galaxies; to Jay Strader and Connie Rockosi for Willman 1 data; to Juerg Diemand, Michael Kuhlen, and Piero Madau for making the data from the Via Lactea simulation publicly available; and to John Beacom, Nicolas Martin, and Joe Wolf for useful discussions. J. S. B., L. E. S., and M.K. are supported in part by NSF grant AST-0607746. Work at LANL was carried out under the auspices of the NNSA of the US Department of Energy at Los Alamos National Laboratory under contract DE-AV52-06NA25396. J. D. S. gratefully acknowledges the support of a Millikan Fellowship provided by Caltech.
Funding AgencyGrant Number
Department of Energy (DOE)DE-AV52-06NA25396
Robert A. Millikan FellowshipUNSPECIFIED
Subject Keywords:cosmology: theory; dark matter
Issue or Number:2
Record Number:CaltechAUTHORS:20090427-155110826
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:14094
Deposited By: Tony Diaz
Deposited On:07 Aug 2009 19:02
Last Modified:15 Nov 2019 04:23

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