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Title: Is the gamma-ray source 3FGL J2212.5+0703 a dark matter subhalo?

In a previous study, we pointed out that the gamma-ray source 3FGL J2212.5+0703 shows evidence of being spatially extended. If a gamma-ray source without detectable emission at other wavelengths were unambiguously determined to be spatially extended, it could not be explained by known astrophysics, and would constitute a smoking gun for dark matter particles annihilating in a nearby subhalo. With this prospect in mind, we scrutinize the gamma-ray emission from this source, finding that it prefers a spatially extended profile over that of a single point-like source with 5.1σ statistical significance. We also use a large sample of active galactic nuclei and other known gamma-rays sources as a control group, confirming, as expected, that statistically significant extension is rare among such objects. We argue that the most likely (non-dark matter) explanation for this apparent extension is a pair of bright gamma-ray sources that serendipitously lie very close to each other, and estimate that there is a chance probability of ~2% that such a pair would exist somewhere on the sky. In the case of 3FGL J2212.5+0703, we test an alternative model that includes a second gamma-ray point source at the position of the radio source BZQ J2212+0646, and find that the addition of this source alongside a point source at the position of 3FGL J2212.5+0703 yields a fit of comparable quality to that obtained for a single extended source. If 3FGL J2212.5+0703 is a dark matter subhalo, it would imply that dark matter particles have a mass of ~18–33 GeV and an annihilation cross section on the order of σv ~ 10–26 cm(3)/s (for the representative case of annihilations to $$b\bar{b}$$), similar to the values required to generate the Galactic Center gamma-ray excess.
Authors:
 [1] ;  [2] ;  [3]
  1. Univ. of Washington, Seattle, WA (United States); Stanford Univ., Stanford, CA (United States)
  2. Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Univ. of Chicago, Chicago, IL (United States)
  3. The Ohio State Univ., Columbus, OH (United States); Univ. of Chicago, Chicago, IL (United States)
Publication Date:
OSTI Identifier:
1254642
Report Number(s):
FERMILAB-PUB--15-411-A; INT-PUB--16-005; arXiv:1602.07303
Journal ID: ISSN 1475-7516; 1423260; TRN: US1601724
Grant/Contract Number:
AC02-07CH11359
Type:
Accepted Manuscript
Journal Name:
Journal of Cosmology and Astroparticle Physics
Additional Journal Information:
Journal Volume: 2016; Journal Issue: 05; Journal ID: ISSN 1475-7516
Publisher:
Institute of Physics (IOP)
Research Org:
Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS