Compact Binaries as Astrophysical Laboratories and the Promise of Third-Generation Detectors
Open Access
- Author:
- Borhanian, Ssohrab
- Graduate Program:
- Physics
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- March 29, 2021
- Committee Members:
- Bangalore Sathyaprakash, Chair & Dissertation Advisor
Chad Hanna, Major Field Member
Donghui Jeong, Outside Unit & Field Member
Nitin Samarth, Program Head/Chair
David Radice, Major Field Member - Keywords:
- Gravitational Waves
General Relativity
Compact Binaries
Fisher Information
Cosmology
Astronomy
Third-Generation Detectors - Abstract:
- The detection of the gravitational-wave event GW150914 not only confirmed Einstein’s prediction of the existence of gravitational waves, but marked the onset of gravitational- wave astronomy. In the following five years the LIGO and Virgo observatories cataloged a total of 50 detections of gravitational-wave events, emitted during the coalescences of binary systems at distances of up to 14 billion light years from Earth. The information carried by these signals allowed the science community, amongst other things, to challenge existing stellar evolution models that could not predict the observed massive black holes, identify binary neutron star mergers as sources of heavy elements and sources of gamma- ray bursts, test general relativity in the strong-field regime otherwise inaccessible to us, and measure the Hubble constant in a first effort to perform precision cosmology with gravitational-wave signals and to eventually aid the resolution of the Hubble-Lemaître tension. As part of an effort to develop the science case for a next-generation detector proposal in the United States, I developed an open-source Python package, gwbench, building on the core concepts of the Fisher information formalism, to benchmark the phenomenology of large gravitational-wave source populations for arbitrary detector network configurations. Using gwbench, I performed a large-scale, comparative study of the relative performance of plausible candidates for global detector networks of the next decades, examining (i) detection efficiencies and rates, (ii) signal visibility and measurement qualities of binary parameters, and (iii) the potential for multi-messenger astronomy in synergy with electromagnetic telescopes. gwbench further enabled me to demonstrate that there is an observable population of golden dark sirens—compact binary coalescences without electromagnetic counterparts—that could facilitate the resolution of the Hubble-Lemaître tension in the next five years and would enable per-event, high-precision cosmology. I further contributed to an investigation of multibanding with future-generation, ground- and space-based detectors as a tool to constrain parametric deviations from general relativity and illustrated, using gwbench, the computational feasibility of multibanding via archival searches in LISA’s data. Finally, I examined the phenomenology of binary black hole mergers and demonstrated a deeper connection of the GWs emitted by the inspiraling binary system and the ringing remnant black hole, tracing post-Newtonian-like signatures in the amplitudes of several gravitational-wave modes from the inspiral into the ringdown signal.