Mo: Electromagnetically probing the end stages of LISA-detectable white dwarf binaries / Shin: Probing the gas content of a cosmic filamentary structure with a fast radio burst

Speaker: Geoffrey Mo (MIT) / Kaitlyn Shin (MIT) In Person and zoom 

Zoom info: https://stanford.zoom.us/j/98604058568

Mo: Gravitational wave and electromagnetic observations offer complementary insights into compact binaries as they form, evolve, and die. With even the very formation of compact binaries poorly understood, I will introduce a novel technique using mid-infrared data to reveal common envelope ejection leading to LISA-detectable white dwarf binaries that ultimately end as Type Ia supernovae. I will also describe an upcoming Hubble time-domain survey of the globular cluster 47 Tuc, which is predicted to be a prolific dynamical factory of exotic compact binaries. The upcoming Rubin Observatory's unprecedented grasp promises to yield dramatic new insights into these multimessenger sources.

Shin: The majority of baryons in the Universe reside in diffuse regions difficult to study with most observational techniques. Fast radio bursts (FRBs) are unique probes of extragalactic ionized baryonic structure since each signal, through its burst properties, holds information about all ionized matter it encounters along its sightline. I present FRB 20200723B, localized to a host galaxy in a cosmic sheet filamentary structure on the outskirts of the Virgo Cluster. Using its burst properties, I observationally constrain the free electron density of this filamentary structure, demonstrating the first use of an FRB to directly probe the gas content of the cosmic web. I also investigate the origins of the unusually large pulse-broadening of this FRB and propose it comes from an H II region within the host galaxy. Upcoming CHIME/FRB catalogs promise to revolutionize our understanding of the diffuse baryonic distribution using FRBs.