2026/02/24 by Alberto Magaraggia, Nico Cappelluti · 1 voice
Physics and Astronomy · #astro-ph.CO #astro-ph.HE
paper · pdf · doi:10.3847/1538-4357/ae48f9
arxiv published 2026/02/24 · arxiv updated 2026/05/11
The detection of sub-solar mass black holes is a milestone of modern astrophysics as it would open a window either onto new stellar physics or could potentially unveil the nature of Dark Matter as Primordial Black Holes (PBHs). On November 12, 2025, the LIGO-Virgo-KAGRA (LVK) collaboration reported the compact binary merger candidate S251112cm, a system with no obvious electromagnetic counterpart, consistent with binary black hole merger with a chirp mass in the range 0.1-0.87 M_\odot. The probability that at least one component has mass <1 M\odot is >99%. Inspired by this trigger, we tested if a population of PBHs formed at Quantum Chromodynamics epoch with a broad mass function could account for a signal of this type. Our results, corresponding to a predicted event rate of 0.8 yr-1 as seen by LVK O3b, suggest that the observed merger rate of 0.23+0.86-0.218 yr-1 (95% C.L.) if the trigger is confirmed as an astrophysical event would be compatible with such a model. Our predicted detection rate is also in agreement with current LVK expectations for stellar-mass binaries, remaining consistent with a scenario in which a non-negligible fraction of the 3-200 M_\odot mergers observed by LVK originate from Primordial Black Holes. If confirmed, this detection would place a lower limit to the PBH abundance fPBH>0.04 for our adopted model.