Ph.D. Thesis Defenses
Past Ph.D. Thesis Defenses

Astrophysics and Cosmology with Gravitational Waves
May 7, 2020 | Zoom Room (online) | 1:00 PM | PhD Advisors: Hsiao-Wen Chen; Daniel E. Holz | PhD Thesis Defense
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Maya Fishbach

"Maya has done influential work in the new field of gravitational-wave astrophysics. She is a leader in the population analysis of gravitational-wave sources, and her high-impact results include recognizing the upper mass gap of binary black holes, standard siren measurements of the Hubble constant using both counterpart and statistical approaches, a new probe of cosmology using a feature from pair-instability supernovae, and novel methods to explore mass and spin distributions as probes of compact binary formation channels."
- Daniel E. Holz, Ph.D. advisor

Thesis Abstract: Starting with the first gravitational-wave detection in September 2015, the LIGO and Virgo gravitational-wave detectors are revealing a new astrophysical population of merging black holes and neutron stars. My thesis focuses on the astrophysical and cosmological lessons enabled by the rapidly growing catalog of gravitational-wave detections. In the first part of the talk, I will describe the properties of the binary black hole population, including the shape of the black hole mass function, the distribution of spins, and the merger rate and its evolution in cosmic time. These results include evidence for missing black holes in the mass range 50-100 solar masses, a preference for pairings between equal mass black holes, and evidence that the merger rate evolves with redshift. I will discuss the implications of these findings for stellar evolution, supernova theory, and the formation history of black holes. The second part of my talk will focus on gravitational-wave cosmology, and the potential of gravitational-wave signals to measure the Hubble constant.