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

Abstract

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:
ORCiD logo [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:
Research Org.:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
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
Resource Type:
Journal Article: 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)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

Citation Formats

Bertoni, Bridget, Hooper, Dan, and Linden, Tim. Is the gamma-ray source 3FGL J2212.5+0703 a dark matter subhalo?. United States: N. p., 2016. Web. doi:10.1088/1475-7516/2016/05/049.
Bertoni, Bridget, Hooper, Dan, & Linden, Tim. Is the gamma-ray source 3FGL J2212.5+0703 a dark matter subhalo?. United States. doi:10.1088/1475-7516/2016/05/049.
Bertoni, Bridget, Hooper, Dan, and Linden, Tim. Mon . "Is the gamma-ray source 3FGL J2212.5+0703 a dark matter subhalo?". United States. doi:10.1088/1475-7516/2016/05/049. https://www.osti.gov/servlets/purl/1254642.
@article{osti_1254642,
title = {Is the gamma-ray source 3FGL J2212.5+0703 a dark matter subhalo?},
author = {Bertoni, Bridget and Hooper, Dan and Linden, Tim},
abstractNote = {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.},
doi = {10.1088/1475-7516/2016/05/049},
journal = {Journal of Cosmology and Astroparticle Physics},
number = 05,
volume = 2016,
place = {United States},
year = {Mon May 23 00:00:00 EDT 2016},
month = {Mon May 23 00:00:00 EDT 2016}
}

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