Putting all the X in one basket: Updated X-ray constraints on sub-GeV Dark Matter

Sub-GeV dark matter particles can annihilate or decay producing e^\pm pairs which upscatter the low-energy photon fields in the Galaxy and generate an X-ray emission (via the Inverse Compton effect). Using X-ray data from XMM-Newton, INTEGRAL, NuSTAR and Suzaku, we derive new constraints on this class of dark matter (DM). For annihilating DM, they are significant for m_DM > 100 MeV, and dominant if DM is p-wave annihilating. For decaying DM, they are the most stringent to date in the range m_DM ~400 MeV - 3 GeV$.