Can substructure in the Galactic halo explain the ATIC and PAMELA results?

Journal Article · Tue Dec 15 04:00:00 EST 2009 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.80.123513· OSTI ID:21313568

Elahi, Pascal J; Widrow, Lawrence M ^[1]; Thacker, Robert J ^[2]

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1. Department of Physics, Engineering Physics and Astronomy, Queen's University, Kingston, Ontario (Canada)
2. Department of Astronomy and Physics, Saint Mary's University, Halifax, Nova Scotia (Canada)

Recently, ATIC and PAMELA measured an anomalously large flux of leptonic cosmic rays which may arise from dark matter self-annihilation. While the annihilation signal predicted for a smooth halo is 10{sup 2}-10{sup 3} times smaller than the measured excess, the signal can be boosted by the presence of subhalos. We investigate the feasibility of large boost factors using a new Monte Carlo calculation technique that is constrained by previous simulation work on halo substructure. The model accounts for the observed decrease in the amount of substructure with decreasing halo mass and the scatter in halo structural parameters such as the density concentration parameter. Our results suggest that boost factors of {approx}10{sup 2} are highly unlikely and are ruled out at > or approx. 14{sigma} within the context of our model. We conclude that substructure alone, at least with commonly assumed annihilation cross sections, cannot explain the anomalous flux measured by ATIC and PAMELA.

• OSTI ID: 21313568
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 12 Vol. 80; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS
ANNIHILATION
COSMIC RADIATION
COSMOLOGICAL MODELS
COSMOLOGY
CROSS SECTIONS
DENSITY
MASS
MONTE CARLO METHOD
NONLUMINOUS MATTER
SIMULATION