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arXiv · 1503.05922

Particle dark matter searches outside the Local Group

Marco Regis·Jun-Qing Xia·Alessandro Cuoco·Enzo Branchini·Nicolao Fornengo·Matteo Viel
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Abstract

If dark matter (DM) is composed by particles which are non-gravitationally coupled to ordinary matter, their annihilations or decays in cosmic structures can result in detectable radiation. We show that the most powerful technique to detect a particle DM signal outside the Local Group is to study the angular cross-correlation of non-gravitational signals with low-redshift gravitational probes. This method allows to enhance signal-to-noise from the regions of the Universe where the DM-induced emission is preferentially generated. We demonstrate the power of this approach by focusing on GeV-TeV DM and on the recent cross-correlation analysis between the 2MASS galaxy catalogue and the Fermi-LAT gamma-ray maps. We show that this technique is more sensitive than other extragalactic gamma-ray probes, such as the energy spectrum and angular autocorrelation of the extragalactic background, and emission from clusters of galaxies. Intriguingly, we find that the measured cross-correlation can be well fitted by a DM component, with thermal annihilation cross section and mass between 10 and 100 GeV, depending on the small-scale DM properties and gamma-ray production mechanism. This solicits further data collection and dedicated analyses.

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Marco Regis, Jun-Qing Xia, Alessandro Cuoco, Enzo Branchini, Nicolao Fornengo, Matteo Viel. 2015-05-21. Particle dark matter searches outside the Local Group. https://doi.org/10.1103/physrevlett.114.241301

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