INTEGRAL x-ray constraints on sub-GeV dark matter

Light dark matter (DM), defined here as having a mass between 1 MeV and about 1 GeV, is an interesting possibility both theoretically and phenomenologically, at one of the frontiers of current progress in the field of DM searches. Its indirect detection via gamma rays is challenged by the scarcity of experiments in the MeV-GeV region. We look therefore at lower-energy x-ray data from the INTEGRAL telescope, and compare them with the predicted DM flux. We derive bounds which are competitive with existing ones from other techniques. Crucially, we include the contribution from inverse Compton scattering on galactic radiation fields and the cosmic microwave background, which leads to much stronger constraints than in previous studies for DM masses above 20 MeV.