Poisson and seed clustering of primordial black holes may relax microlensing bounds while explaining ultra-faint dwarfs and little red dots
Clustering from Poisson and seed effects allows solar-mass PBHs to evade inner-halo microlensing limits while seeding observed dwarf galaxies and high-z red dots. Binary mergers inside surviving clusters dominate the LIGO rate. Non-Gaussian tails could further relax constraints.
Next steps include targeted searches for wide-binary disruption in the outer halo and forecasts for the Einstein Telescope to measure the clustered merger-rate component. If the rotation-curve decline is confirmed by Gaia DR4, solar-mass PBHs could furnish the bulk of dark matter without violating current data.
Kuhnel et al.: Gaia DR4 will show a statistically significant decline in the rotation curve beyond 20 kpc at >3 sigma if clustered solar-mass PBHs comprise >30 percent of the halo dark matter within 18 months.
Sources (2)
- [1]Primary Source(https://arxiv.org/abs/2610.28723)
- [2]Supporting Source(https://arxiv.org/abs/2007.10722)