The Astrophysical Context of Gravitational Wave Events

We live in an era of breakthrough discoveries in gravitational waves (GW) astronomy. Every month or so, such discoveries by LIGO/Virgo have been making headlines because these events’ nature has been far from the expectations. But why are we puzzled? And what is the road ahead for us to a deeper understanding? I discuss two of the puzzling events that LIGO has discovered: 1) The most massive binary black hole merger with masses above the pair-instability limit. After an overview of the physics of pair-instability supernova, I will discuss how a broader perspective on the host environment of binary black holes can hold the key to understanding the nature of such massive systems. 2) The most massive binary neutron star merger. I will present possible scenarios to explain why we have not detected such systems in the radio observations before and how the key to understanding these events might lie in the r-process enrichment in the early universe and magnetic field evolution of neutron stars. Through these two examples, I will conclude that the synergy of electromagnetic-wave astronomy with gravitational wave astronomy is essential for gaining insights into the surprises that are being uncovered with these new observations.