Seeing the invisible with black hole superradiance sourced gravitational waves

Abstract

 In this talk I explain a few our works which revolve around the direct an indirect signals of first order cosmological phase transitions. The former consists of the primary gravitational waves created directly from the phase transitions, whereas the later consists of the secondary gravitational waves from the primordial black holes which can originate from the phase transition. These secondary gravitational waves can arise from the primordial black holes from a few different mechanisms such as gravitational interactions, superradiant instability, etc. Furthermore, these primordial black holes can also acquire small initial spin and we focus on their dependence on the phase transition properties.