Spectral and spatial analysis of the dark matter subhalo candidates among Fermi Large Area Telescope unidentified sources

Abstract

Fermi-LAT unidentified sources (unIDs) have proven to be compelling targets for performing indirect dark matter (DM) searches. In a previous work, we found that among the 1235 unIDs in Fermi-LAT catalogs (3FGL, 2FHL and 3FHL) only 44 of those are DM subhalos candidates. We now implement a spectral analysis to test whether these remaining sources are compatible or not with DM origin. This analysis is executed using almost 10 years of Pass 8 Fermi-LAT data. None of the unIDs are found to significantly prefer DM-induced emission compared to other, more conventional, astrophysical sources. In order to discriminate between pulsar and DM sources, we developed a new method which is based on the source's spectral curvature, peak energy, and its detection significance. We also look for spatial extension, which may be a hint for a DM origin according to our N-body simulation studies of the subhalo population. In addition, we used Gaia DR2 data to search for a potential stellar counterpart to our best DM subhalo candidates and, although no firm associations could be found, one of them coincides with the Sagittarius stream. Finally, previous constraints on the DM annihilation cross section are updated with the new number of remaining DM subhalo candidates among unIDs. Our limits now rule out canonical thermal WIMPs up to masses of 10 GeV for $b\bar{b}$ and 20 GeV for ${\tau }^{+}{\tau }^{-}$ annihilation channels, in this way being as sensitive and complementary to those obtained from other targets and probes.

27 pages, 10 figures, JCAP accepted. Matches the accepted version

References in corpus (13)

• The NumPy array: a structure for efficient numerical computation
• The Gaia mission
• Precise Relic WIMP Abundance and its Impact on Searches for Dark Matter Annihilation
• Search for dark matter annihilations towards the inner Galactic halo from 10 years of observations with H.E.S.S
• A blueprint for detecting supersymmetric dark matter in the Galactic halo
• Dark Matter: A Primer
• Dark matter subhalos and the dwarf satellites of the Milky Way
• Fitting the Gamma-Ray Spectrum from Dark Matter with DMFIT: GLAST and the Galactic Center Region
• Fourteen candidate RR Lyrae star streams in the inner Galaxy
• 3FGLzoo. Classifying 3FGL Unassociated Fermi-LAT Gamma-ray Sources by Artificial Neural Networks
• Unidentified Gamma-ray Sources as Targets for Indirect Dark Matter Detection with the Fermi-Large Area Telescope
• Identifying the 3FHL catalog: I. Archival Swift Observations and Source Classification
• Testing the dark matter subhalo hypothesis of the gamma-ray source 3FGL J2212.5+0703

Cited by in corpus (4)

• TeV Dark Matter Searches in the Extragalactic Gamma-Ray Sky
• Shedding light on low-mass subhalo survival and annihilation luminosity with numerical simulations
• Search for dark matter annihilation signals from unidentified Fermi-LAT objects with H.E.S.S
• Spatial extension of dark subhalos as seen by Fermi-LAT and implications for WIMP constraints