Where are the Fermi lines coming from?

Journal Article · Fri Mar 01 04:00:00 EST 2013 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2013/03/035· OSTI ID:22282973

Rao, Kanishka; Whiteson, Daniel ^[1]

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1. Dept. of Physics and Astronomy, UC Irvine, Irvine, CA (United States)

We estimate the spatial locations of sources of the the observed features in the Fermi-LAT photon spectrum at E{sub γ} = 110 and E{sub γ} = 130 GeV. We determine whether they are consistent with emission from a single source, as would be expected in their interpretation as γγ and γZ lines from dark matter annhiliation, as well as whether they are consistent with a dark matter halo positioned at the center of the galaxy. We take advantage of the per-photon measured incident angle in reconstructing the line features. In addition, we use a data-driven background model rather than making the assumption of a feature-less background. We localize the sources of the features at 110 and 130 GeV. Assuming an Einasto (NFW) density model we find the 130 GeV line to be offset from the Galactic center by 285 (280) pc, the 110 GeV line by 60 (30) pc with a large relative separation of 220 (240) pc. However, we find this displacement of each source from the Galactic center, as well as their relative displacement to be statistically consistent with a single Einasto or NFW dark matter halo at the center of the galaxy.

• OSTI ID: 22282973
• Journal Information: Journal of Cosmology and Astroparticle Physics, Journal Name: Journal of Cosmology and Astroparticle Physics Journal Issue: 03 Vol. 2013; ISSN 1475-7516
• Country of Publication: United States
• Language: English

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