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A luminosity constraint on the origin of unidentified high energy sources

Siegal-Gaskins, J. M. and Pavlidou, V. and Olinto, A. V. and Brown, C. and Fields, B. D. (2009) A luminosity constraint on the origin of unidentified high energy sources. Journal of Physics G: Nuclear and Particle Physics, 36 (5). 055201. ISSN 0954-3899.

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The identification of point sources poses a great challenge for the high energy community. We present a new approach to evaluate the likelihood of a set of sources being a Galactic population based on the simple assumption that galaxies similar to the Milky Way host comparable populations of gamma-ray emitters. We propose a luminosity constraint on Galactic source populations which complements existing approaches by constraining the abundance and spatial distribution of any objects of Galactic origin, rather than focusing on the properties of a specific candidate emitter. We use M31 as a proxy for the Milky Way and demonstrate this technique by applying it to the unidentified EGRET sources. We find that it is highly improbable that the majority of the unidentified EGRET sources are members of a Galactic halo population (e.g., dark matter subhalos), but that current observations do not provide any constraints on all of these sources being Galactic objects if they reside entirely in the disk and bulge. Applying this method to upcoming observations by the Fermi Gamma-ray Space Telescope has the potential to exclude association of an even larger number of unidentified sources with any Galactic source class.

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Additional Information:© 2009 IOP Publishing Ltd. Received 13 December 2008. Published 9 April 2009. We thank J Beacom, A Strong, O Reimer, and I Grenier for insightful comments and suggestions relating to this work, and D Thompson for his advice with regard to the observational upper limits from the EGRET data. We are extremely grateful to S Digel for detailed discussions about the EGRET upper limits and diffuse backgrounds. This work was supported by the Kavli Institute for Cosmological Physics at the University of Chicago through grants NSF PHY-0114422 and NSF PHY-0551142 and an endowment from the Kavli Foundation and its founder Fred Kavli. Support for VP was provided by NASA through the GLAST Fellowship Program, NASA Cooperative Agreement: NNG06DO90A.
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Kavli FoundationUNSPECIFIED
Subject Keywords:astronomical telescopes; dark matter; Galaxy; gamma-ray sources (astronomical)
Issue or Number:5
Record Number:CaltechAUTHORS:20090812-101116056
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:14985
Deposited By: Tony Diaz
Deposited On:13 Aug 2009 15:18
Last Modified:03 Oct 2019 00:54

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