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Sensitivity of CTA to dark matter signals from the Galactic Center

Pierre, Mathias and Siegal-Gaskins, Jennifer M. and Scott, Pat (2014) Sensitivity of CTA to dark matter signals from the Galactic Center. Journal of Cosmology and Astroparticle Physics, 2014 (6). Art. No. 24. ISSN 1475-7516.

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The Galactic Center is one of the most promising targets for indirect detection of dark matter with gamma rays. We investigate the sensitivity of the upcoming Cherenkov Telescope Array (CTA) to dark matter annihilation and decay in the Galactic Center. As the inner density profile of the Milky Way's dark matter halo is uncertain, we study the impact of the slope of the Galactic density profile, inwards of the Sun, on the prospects for detecting a dark matter signal with CTA. Adopting the Ring Method to define the signal and background regions in an ON-OFF analysis approach, we find that the sensitivity achieved by CTA to annihilation signals is strongly dependent on the inner profile slope, whereas the dependence is more mild in the case of dark matter decay. Surprisingly, we find that the optimal choice of signal and background regions is virtually independent of the assumed density profile. For the fiducial case of a Navarro-Frenk-White profile, we find that CTA will be able to probe annihilation cross-sections well below the canonical thermal relic value for dark matter masses from a few tens of GeV up to similar to 5 TeV for annihilation to T^+T^- and will achieve only a slightly weaker sensitivity for annihilation to bb or µ^+µ^-. CTA will improve significantly on current sensitivity to annihilation signals for dark matter masses above similar to 100 GeV, covering parameter space that is complementary to that probed by searches with the Fermi Large Area Telescope. The interpretation of apparent excesses in the measured cosmic-ray electron and positron spectra as signals of dark matter decay will also be testable with CTA observations of the Galactic Center. We demonstrate that both for annihilation and for decay, including spectral information for hard channels (such as µ^+µ^- and Ƭ^+T^- leads to enhanced sensitivity for dark matter masses above m_(DM) similar to 200 GeV.

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Additional Information:© 2014 IOP Publishing Ltd and Sissa Medialab. Received January 31, 2014. Revised April 22, 2014. Accepted May 17, 2014. Published June 11, 2014. It is a pleasure to thank Jan Conrad, Michele Doro, Christian Farnier, Emmanuel Moulin, Rene Ong, Massimo Persic, Miguel Ángel Sánchez-Conde, Louie Strigari, Vladimir Vassiliev, Christoph Weniger, and Matthew Wood for helpful discussions. M.P. acknowledges the Moore Center for Theoretical Cosmology and Physics for support and Caltech for hospitality. J.S.-G. acknowledges support from NASA through Einstein Postdoctoral Fellowship grant PF1-120089 awarded by the Chandra X-ray Center, which is operated by the Smithsonian Astrophysical Observatory for NASA under contract NAS8-03060. P.S. is supported by the Banting Fellowship, administered by NSERC for the Canadian Tri-Agency Research Councils. JSG and PS thank the Kavli Institute for Theoretical Physics for hospitality.
Group:Moore Center for Theoretical Cosmology and Physics
Funding AgencyGrant Number
Caltech Moore Center for Theoretical Cosmology and PhysicsUNSPECIFIED
NASA Einstein Postdoctoral FellowshipPF1-120089
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
Subject Keywords:dark matter experiments; gamma ray theory; gamma ray experiments
Classification Code:PACS: 95.35.+d, 95.30.Cq, 98.35.Jk, 95.55.Ka, 96.50.db, 29.40.Ka
Record Number:CaltechAUTHORS:20150109-111350090
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Official Citation:Sensitivity of CTA to dark matter signals from the Galactic Center Mathias Pierre et al JCAP06(2014)024
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:53471
Deposited By: Ruth Sustaita
Deposited On:09 Jan 2015 20:54
Last Modified:09 Jan 2015 23:50

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