PhD Thesis Presentation: Topics in Compact Object Astrophysics and Fundamental Physics with Current and Future Gravitational Wave Observations

PhD Candidate

Zhenwei Lyu

Abstract

The thesis is devoted to compact object astrophysics and fundamental physics, current and future gravitational wave (GW) observations. Since the first detection of GW event GW150914 by LIGO in 2015, there have been more than 90 transients observed by the LIGO, Virgo and KAGRA collaboration up till now. Additionally, more observations of stellar mass compact binaries would be detected by current and the second generation detectors as well as observations of Extreme Mass Ratio Inspirals (EMRIs) by future space-based gravitational wave detectors such as LISA, TianQin and TaiJi.

In this thesis, we study the detections and constraints on potential effects postulated by Einstein's general relativity (GR) and beyond, such as probing tidal-induced i-mode in inspiraling binary neutron stars (BNSs), searching nuclear coupling of axions from the BNSs, and constraining Einstein-dilation Gauss-Bonnet (EdGB) gravity from black hole neutron star (BHNS) events.

Besides, we propose a new hybrid waveform model, which illustrates comparable accuracy in characterizing tidal effects as the effective-one-body (EOB) waveform and numerical relativity simulation. We also investigate an important EMRIs formation channel driven by active galactic nuclei (AGN) accretion disk. we forecast that AGN EMRIs will contribute an important or even dominant fraction of all detectable EMRIs by spaceborne gravitational wave detectors and the AGN channel is much more promising to produce mass-gap EMRIs.

Examination Committee

• Dr. Ralf Gellert, Chair
• Dr. Huan Yang, Advisor
• Dr. Eric Poisson
• Dr. Daniel Siegel
• Dr. Leo Stein, External Examiner (University of Mississippi)