Astro Seminar: Brian C. Seymour

Speaker: Brian C. Seymour (Niels Bohr Institute)

Title: A Deep Dive into Environmental Effects of Hierarchical Triples

Abstract: So far, the gravitational waveforms observed by LVK are consistent with coalescences of isolated binaries in a vacuum. In the future, as sensitivities at low frequencies improve, the increased signal duration will allow us to resolve subtle modulations induced by the astrophysical environment such as gas effects in accretion disks, gravitational lensing, or distant third bodies. In this talk, I will discuss how the presence of a third body modifies the gravitational waves with a focus on binaries orbiting AGN. These exhibit rich phenomenology such as Rømer time delay, angular momentum precession, and potential lensing by the tertiary. In addition to describing advancements in modeling, I will evaluate the prospects for their detection and characterization using LISA and future decihertz observatories.