Detection of a Gamma-Ray Source in the Galactic Center Consistent with Extended Emission from Dark Matter Annihilation and Concentrated Astrophysical Emission

By K. Abazajian, M. Kaplinghat. 2012

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We show the existence of a statistically significant, robust detection of a gamma-ray source in the Milky Way Galactic Center that is consistent with a spatially extended signal using about 4 years of Fermi-LAT data. The gamma-ray flux is consistent with annihilation of dark matter particles with a thermal annihilation cross-section if the spatial distribution of dark matter particles is similar to the predictions of dark matter only simulations. We find statistically significant detections of an extended source with gamma-ray spectrum that is consistent with dark matter particle masses of approximately 10 GeV to 1 TeV annihilating to b/b-bar quarks, and masses approximately 10 GeV to 30 GeV annihilating to tau+ tau- leptons. However, a part of the allowed region in this interpretation is in conflict with constraints from Fermi observations of the Milky Way satellites. The biggest improvement over the fit including just the point sources is obtained for a 30 GeV dark matter particle annihilating to b/b-bar quarks. The gamma-ray intensity and spectrum are also well fit with emission from a millisecond pulsar (MSP) population following a density profile like that of low-mass X-ray binaries observed in M31. The greatest goodness-of-fit of the extended emission is with spectra consistent with known astrophysical sources like MSPs in globular clusters or cosmic ray bremsstrahlung on molecular gas. Therefore, we conclude that the bulk of the emission is likely from an unresolved or spatially extended astrophysical source. However, the interesting possibility of all or part of the extended emission being from dark matter annihilation cannot be excluded at present.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/987f1271cb63a6b3daa9d7443acbf049eeb8da78

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Citations in the corpus

DEVELOPMENT OF THE MODEL OF GALACTIC INTERSTELLAR EMISSION FOR STANDARD POINT-SOURCE ANALYSIS OF FERMI LARGE AREA TELESCOPE DATA (2016, background): “In this energy range, several studies have reported emission from the GC region in excess of the expectations from standard emission components (Vitale & Morselli 2009; Hooper & Linden 2011; Abazajian & Kaplinghat 2012; Calore et al. 2015).”
DWARF GALAXY ANNIHILATION AND DECAY EMISSION PROFILES FOR DARK MATTER EXPERIMENTS (2014, background): “…PA 15213; mgwalker@andrew.cmu.edu pecially interesting in the context of recent claims of a Galactic center gamma-ray excess and associated dark matter interpretation (e.g. Hooper & Goodenough 2011; Boyarsky et al. 2011; Abazajian & Kaplinghat 2012, 2013; Abazajian et al. 2014; Daylan et al. 2014).”
The Fermi Galactic Center GeV Excess and Implications for Dark Matter (2017, background): “…of models for interstellar gamma-ray emission and point sources (PSs; e.g., Goodenough & Hooper 2009; Vitale et al. 2009; Hooper & Goodenough 2011; Abazajian & Kaplinghat 2012; Gordon & Macías 2013; Hooper & Slatyer 2013; Calore et al. 2015; Zhou et al. 2015; Ajello et al. 2016; Daylan et al.…”
FERMI-LAT OBSERVATIONS OF HIGH-ENERGY γ-RAY EMISSION TOWARD THE GALACTIC CENTER (2015, methodology): “Analyses of the data toward the region surrounding the GC have been made by various authors (Goodenough & Hooper 2009; Hooper & Goodenough 2011; Abazajian & Kaplinghat 2012; Hooper & Slatyer 2013; Gordon & Macı́as 2013; Huang et al. 2013; Abazajian et al. 2014; Daylan et al. 2014; Calore et al.…”
Gamma Ray Signals from Dark Matter: Concepts, Status and Prospects (2012, background): “, they correspond to DM masses in the ∼MeV [209–211], ∼10 GeV [185, 212, 213], ∼100 GeV [214], ∼TeV [61, 215–217] (sometimes with possible counterparts at radio frequencies [218–220]) or even multi-TeV range [221–223].”
Background model systematics for the Fermi GeV excess (2014, methodology): “During the last few years the presence of a gamma-ray excess at GeV energies and towards the GC has been suggested by a sequence of studies performed using Fermi -LAT gammaray data [49, 50, 53–57, 65, 125, 140].”