Galactic Center gamma-ray ``excess'' from an active past of the Galactic Centre?

By Jovana Petrovic, P. Serpico, G. Zaharijas. 2014

148 citations recorded by the source corpus.

Several groups have recently claimed evidence for an unaccounted gamma-ray excess over the diffuse backgrounds at few GeV in the Fermi-LAT data in a region around the Galactic Center, consistent with a dark matter annihilation origin. We demonstrate that the main spectral and angular features of this excess can be reproduced if they are mostly due to inverse Compton emission from high-energy electrons injected in a burst event of ∼ 1052÷1053 erg roughly 𝒪(106) years ago. We consider this example as a proof of principle that time-dependent phenomena need to be understood and accounted for—together with detailed diffuse foregrounds and unaccounted ``steady state'' astrophysical sources—before any robust inference can be made about dark matter signals at the Galactic Center. In addition, we point out that the timescale suggested by our study, which controls both the energy cutoff and the angular extension of the signal, intriguingly matches (together with the energy budget) what is indirectly inferred by other evidences suggesting a very active Galactic Center in the past, for instance related to intense star formation and accretion phenomena.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/54546ec02ece7cb78cba2c56822d25387b7f2526

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Citations in the corpus

Background model systematics for the Fermi GeV excess (2014, methodology): “urst-like events during an active past of our Galaxy may represent a viable mechanism for producing gamma rays in the inner Galaxy with the observed spectrum and morphology. Hadronic [75] or leptonic [76] scenarios might explain some of the observed excess features at high latitudes. In this paper, ”
Dark nuclei. I. Cosmology and indirect detection (2014, methodology): “rks obtained in Ref. [92].7 We calculate the J-factor for the best-t NFW [94] prole of Ref. [81] with 6It should be noted that plausible interpretations based on SM physics have also been suggested [90,91], and thus we use this DM hint as an interesting scenario with which to demonstrate the possibl”
A review of indirect searches for particle dark matter (2016, background): “It has been suggested that the excess could potentially be explained by inverse Compton scattering by high-energy electrons injected in the past during a burst of activity at the Galactic Center such as accretion and star formation [126].”
A tale of tails: Dark matter interpretations of the Fermi GeV excess in light of background model systematics (2014, background): “…astrophysical explanations, like the emission from an unresolved population of pointlike sources concentrated in the very center of the Galaxy (see [28 – 31] for relevant discussions) or the injection of leptons and/or protons during a burst event at the GC some kilo-/mega-years ago [32,33].”