Title: A model-independent analysis of the Fermi Large Area Telescope gamma-ray data from the Milky Way dwarf galaxies and halo to constrain dark matter scenarios

Abstract

Here, we implemented a novel technique to perform the collective spectral analysis of sets of multiple gamma-ray point sources using the data collected by the Large Area Telescope onboard the Fermi satellite. The energy spectra of the sources are reconstructed starting from the photon counts and without assuming any spectral model for both the sources and the background. In case of faint sources, upper limits on their fluxes are evaluated with a Bayesian approach. Our analysis technique is very useful when several sources with similar spectral features are studied, such as sources of gamma rays from annihilation of dark matter particles. We also present the results obtained by applying this analysis to a sample of dwarf spheroidal galaxies and to the Milky Way dark matter halo. The analysis of dwarf spheroidal galaxies yields upper limits on the product of the dark matter pair annihilation cross section and the relative velocity of annihilating particles that are well below those predicted by the canonical thermal relic scenario in a mass range from a few GeV to a few tens of GeV for some annihilation channels.

Authors:

Mazziotta, M. N. ^[1]; Loparco, F. ^[2]; de Palma, F. ^[1]; Giglietto, N. ^[2]

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+ Show Author Affiliations

1. National Inst. of Nuclear Physics, Bari (Italy)
2. National Inst. of Nuclear Physics and, Bari (Italy)

Publication Date:

Sun Jul 22 00:00:00 EDT 2012

Research Org.:

SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)

Sponsoring Org.:

USDOE

Contributing Org.:

Fermi LAT Collaboration

OSTI Identifier:

1356669

Grant/Contract Number:  

AC02-76SF00515

Resource Type:

Accepted Manuscript

Journal Name:

Astroparticle Physics

Additional Journal Information:

Journal Volume: 37; Journal Issue: C; Journal ID: ISSN 0927-6505

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

79 ASTRONOMY AND ASTROPHYSICS; DM searches; DSph galaxies; Milky Way halo; Bayesian confidence intervals; Stacking analysis