Unidentified Gamma-ray Sources as Targets for Indirect Dark Matter Detection with the Fermi-Large Area Telescope

Author/Creator ORCID

Date

2019-06

Department

Program

Citation of Original Publication

Coronado-Blázquez, Javier and Sánchez-Conde, Miguel A. and Domínguez, Alberto and Aguirre-Santaella, Alejandra and Mauro, Mattia Di and Mirabal, Néstor and Nieto, Daniel and Charles, Eric, Unidentified gamma-ray sources as targets for indirect dark matter detection with the Fermi-Large Area Telescope, Journal of Cosmology and Astroparticle Physics, IOP Publishing, 2019, http://dx.doi.org/10.1088/1475-7516/2019/07/020

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This is the version of the article before peer review or editing, as submitted by an author to Journal of Cosmology and Astroparticle Physics.  IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at 10.1088/1475-7516/2019/07/020.

Subjects

Abstract

One of the predictions of the ΛCDM cosmological framework is the hierarchical formation of structure, giving rise to dark matter (DM) halos and subhalos. When the latter are massive enough they retain gas (i.e., baryons) and become visible. This is the case of the dwarf satellite galaxies in the Milky Way (MW). Below a certain mass, halos may not accumulate significant amounts of baryons and remain completely dark. However, if DM particles are Weakly Interacting Massive Particles (WIMPs), we expect them to annihilate in subhalos, producing gamma rays which can be detected with the Fermi satellite. Using the three most recent point-source Fermi Large Area Telescope (LAT) catalogs (3FGL, 2FHL and 3FHL), we search for DM subhalo candidates among the unidentified sources, i.e., sources with no firm association to a known astrophysical object. We apply several selection criteria based on the expected properties of the DM-induced emission from subhalos, which allow us to significantly reduce the list of potential candidates. Then, by characterizing the minimum detection flux of the instrument and comparing our sample to predictions from the Via Lactea II (VL-II) N-body cosmological simulation, we place conservative and robust constraints on the hσvi − mDM parameter space. For annihilation via the τ+τ− channel, we put an upper limit of 4 × 10−26 (5 × 10−25) cm3 s−1 for a mass of 10 (100) GeV. A critical improvement over previous treatments is the repopulation we made to include low-mass subhalos below the VL-II mass resolution. With more advanced subhalo candidate filtering the sensitivity reach of our method can potentially improve these constraints by a factor 3 (2) for τ+τ− (b¯b) channel.