Probing ultralight primordial black hole dark matter with XMM telescopes

Primordial black holes (PBHs), originating from the gravitational collapse of large overdensities in the early Universe, emerge as a compelling dark matter (DM) candidate across a broad mass range. Of particular interest are ultra-light PBHs with masses around 10¹⁴ to 10¹⁷ g, which are typically probed by searching their evaporation products. Using the soft X-ray signal measured by the XMM telescopes, we derive constraints on the fraction of PBHs dark matter with masses in the range 10¹⁵-10¹⁶ g. We find that observations exclude fraction f>10-6 at 95% C.L. for mass MPBH=1015 g.