Astrophysics, cosmology, and fundamental interactions with gravitational waves

Abstract

Several unresolved mysteries remain in our understanding of the universe that can be elucidated with a growing catalog of gravitational wave~(GW) and multi-messenger observations of compact binary coalescences~(CBCs). Current and future catalogs, assisted by robust modeling and scalable inference frameworks, will lead to new insights into the poorly understood physics of compact binary formation, independent measurements of the cosmological expansion, and unprecedented empirical probes into the very nature of fundamental interactions. The scientific potential of GW observations from CBCs is significantly enhanced through the detection of their multi-messenger counterparts. Similarly, multi-probe explorations of compact object universal properties that combine GW and electromagnetic observations of different systems comprising similar kinds of compact objects highly complement the prospects of GW observations in facilitating major scientific breakthroughs. With a large number of new observations expected shortly by current and next-generation detectors, discoveries capable of revolutionizing modern physics are imminent. In this thesis, I will discuss my contributions to GW astronomy which primarily involve extracting new observational insights into the astrophysics of compact binary formation, the cosmic expansion history, the properties of matter at extreme densities, and tests of general relativity, from growing GW catalogs. I will also discuss my contributions to multi-messenger astronomy, particularly in the field of low-latency categorization of GW candidates to assess the possibility of them being accompanied by multi-messenger counterparts.