2026/07/19 by Hong-Rui Tao, Huan Zhou, Cheng-Gang Shao +2
#astro-ph.CO #astro-ph.HE
Primordial black holes (PBHs) are not only considered as a candidate for dark matter, but also as potential sources of gravitational waves from binary black hole mergers by the LIGO-Virgo-KAGRA and as seeds for the supermassive black holes observed by the James-Webb Space Telescope, thereby remaining intense interest in cosmology and astrophysics. Fast radio bursts (FRBs) are bright millisecond-duration radio transients whose physical origin remains elusive, which have rapidly developed into one of the most active and rapidly evolving fields in astronomy. The microlensing effect of FRBs offers a clean and powerful probe of PBHs, especially in the mass range above stellar-mass window. In this work, we derive a complete transformation that converts any upper limit on the abundance of PBHs originally derived for `bare' PBHs with monochromatic mass distribution, into the corresponding constraint on `dressed' PBHs with arbitrary extended mass distributions. Based on this framework, we estimate the future constraints on the dressed PBH abundance \(fPBH\) from FRB observations assuming an expected sample of \(105\) FRBs accumulated over the next decade well within the projected detection capabilities of SKA. Our results indicate that including halo enhancement tightens the upper limits on \(fPBH\) by approximately one order of magnitude, with the most stringent constraint reaching \(∼10-4\) for the typical mass range from stellar-mass to intermediate-mass black holes.