National Institute of Chemical Physics and Biophysics
Universidad Antonio Nariño
Even if primordial black holes (PBHs) make up only a small fraction of the total dark matter abundance, their existence can be probed by various gravitational wave (GW) signals. Nearby PBHs that decouple from the cosmic expansion in the early Universe will inevitably form binaries. If PBHs comprise more than 0.1% of dark matter, the mergers of such binaries may serve as the progenitors of the LIGO/Virgo GW events and also generate a GW background detectable by future GW experiments. Additionally, PBH formation from large curvature fluctuations is accompanied by a secondary GW signal. We show how the recent NANOGrav signal may be interpreted as a stochastic GW background related to PBH formation.