GW Backgrounds associated with PBHs

Understand

PBH formation requires high-density regions in the (random) density field filling the primordial universe.

• While only the largest (and so rarest) overdensities collapse to form PBHs, the rest cause large anisotropic stresses, which are the source of GWs.
• We provide an overview of the theoretical aspects of the GW backgrounds associated with PBHs from large primordial fluctuations.
• We consider GW backgrounds associated with PBH formation, PBH reheating and unresolved PBH binaries.