Particle dark matter searches outside the Local Group

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.

6+3 pages, 6+3 figures; v2: corrected a typo and added a ref. v3: minor changes in the main text, Supplemental Material added, to appear in PRL

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Cited by in corpus (10)

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• Tomographic imaging of the Fermi-LAT gamma-ray sky through cross-correlations: A wider and deeper look
• AMS-02 Positron Excess and Indirect Detection of Three-body Decaying Dark Matter
• Condensate flow in holographic models in the presence of dark matter
• Planck Lensing and Cosmic Infrared Background Cross-Correlation with Fermi-LAT: Tracing Dark Matter Signals in the Gamma-Ray Background
• TeV Dark Matter Searches in the Extragalactic Gamma-Ray Sky
• Searching for Signal of Primordial Black Hole from CMB Lensing and $\gamma$-ray Emissions