Detection of Spin Orbit Resonances in Advance Gravitational Wave Detector Era

Abstract

Very recently, LIGO Scientific collaboration has made the first direct detection of gravitational waves (GWs) emitted from two coalescing stellar mass black holes (BHs). This detection, with the advanced GW detectors, has given hope to detect more and more coalescing binaries, helping us to reveal their interesting properties. There exist certain equilibrium configurations in spinning and precessing binaries in which spins of the BHs and orbital angular momentum of the binary remain in a plane (the resonant plane) during their evolution. The spin-orbit resonances have important astrophysical implications as the evolution and subsequent coalescence of super-massive BH binaries in this configuration leads to low recoil velocities of merger remnants. Hence, the final BHs will be retained in their host galaxies that are formed from the merger of smaller galaxies. Moreover, it has been shown that the BH spins in comparable mass stellar mass binary would preferentially lie in a resonant plane when their GWs enter the advanced LIGO frequency band. Therefore, it is highly desirable to investigate the detectability of such systems in advanced GW detector era which can, in turn, improve our perception of their high mass counterparts. The current detection pipelines involve only non-spinning and non-precessing template banks for compact binary searches. In this thesis, we test the performance of these template banks in detecting spin-orbit resonant binaries. We find that the full inspiral-merger-ringdown template banks are performing better in detecting resonant binaries as compared to inspiral-only banks. We show that generically precessing binaries can also be detected with statistically equal probability as resonant binaries. We give equilibrium solutions for the sub-maximally spinning BH binaries, which were not studied in detail previously.