Probing the existence of Primordial Black Holes with Gravitational Waves

Abstract

In recent years gravitational waves have attracted a lot of attention because they are a novel way of studying the properties and mergers of black holes and neutron stars. Now, we use them to probe the existence of a different type of black holes; primordial black holes (PBHs). First, we use the thermal history of the early Universe to infer the PBH mass spectrum. We find that it has peaks at 5 × 10^−4 , 2, 100 and 6 × 10^ 6 M_(Sun)?. From this, we see that PBHs could comprise all of the cold dark matter in the Universe. We then take into account the sensitivity of the LIGO and Virgo detectors during the O2 run and we find that we can detect black hole mergers with masses around 2 and 100 M_(Sun)?, opening up the possibility of probing the existence of PBHs in the near future.