[Colloquium] Physics and Astrophysics using Gravitational Waves

Speaker: Tejaswi Venumadhav Nerella, UCSB

Title: Physics and Astrophysics using Gravitational Waves

Abstract: Gravitational waves have opened a new window on the Universe, allowing us to study merging compact objects such as black holes and neutron stars in unprecedented detail. In this talk, I will discuss recent advances in our understanding of these systems, driven by gravitational-wave observations and informed by new theoretical developments. I will describe new search methods that make use of the richer signal structure predicted by General Relativity to significantly boost the overall detection sensitivity for these rare systems, with the largest gains for binaries with unequal masses or tilted orbits. I will then discuss what the larger catalog of detections reveals about the population of merging compact objects, showing how the distributions of their properties offer clues to how the binaries may have been assembled, and even shed light on their broader astrophysical and cosmological context. Finally, I will turn from astrophysical questions to those of fundamental physics. Gravitational waves offer a unique probe of the equation of state of dense nuclear matter, through the way a neutron star’s tidal deformation imprints itself on the signal emitted by a binary. I will discuss how this effect gives rise to a surprisingly rich range of dynamical phenomena, as internal resonances within the star respond to and modify its tidal interaction during inspiral and merger. Looking ahead, the rapidly growing number of detections from current and future observing runs will expand these opportunities, allowing us to ask ever more detailed questions about both the astrophysics of compact objects and the fundamental physics that governs them.