Aspects of cosmological gravitational waves at Pulsar Timing Arrays with Fabrizio Rompineve

New Physics in the early Universe may feature sources of gravitational waves (GWs), that can be searched for at interferometers and Pulsar Timing Arrays (PTAs). After providing an overview of the recently reported evidence of a nHz stochastic GW background (GWB) from PTAs, we describe general properties of cosmological GWBs that can help in distinguishing them from astrophysical signals, highlighting the relevance of complementary signatures in cosmological datasets. We then focus on cosmic topological defects (specifically, domain walls) as a well-motivated possible source of GWs in the early Universe. In particular, we report on recent progress in the description of their cosmological evolution and their GW signal.

This lecture was made possible by the William C. Ferguson fund.