Precession in GWs
With binary black hole (BBH) mergers accounting for a large proportion of the gravitational wave (GW) events observed by the LIGO-Virgo-KAGRA collaboration, BBH dynamics have received a lot of attention in recent years. Spin precession is a key factor in such dynamics. Spins of the black holes in binaries largely depend on different astrophysical formation channels that result in the formation of BBH systems. Dynamical environments, such as globular clusters, dense stellar regions, and active galactic nuclei, can lead to the formation of BBHs with spins misaligned with the orbital angular momentum.
Due to the misalignment of spins with respect to the orbital angular momentum, the orbit of the binary precesses and nutates around the total angular momentum. Such spin dynamics leave imprints on the emitted GWs, evident from modulations in the polarization, phase, and amplitude of the GW signals. Hence, GW signals can provide insight into various astrophysical properties of the system they originate from via realizations for masses and spins of the compact objects, along with orbital properties, distance to the binary, sky location, etc.
My Research on precession in GWs
I am particularly interested in spin precession effects on GW signals from BBH mergers. I worked on building an (inspiral-only; post-Newtonian) waveform that captures the geometrical nature of the precessional motion. This precession of the orbital angular momentum affects the GW signal on precessional timescales. My focus is to understand the distinguishability of precessing signals from non-precessing signals. We do this by employing matched-filtering techniques; we calculate mismatches, set a distinguishability criterion, and discuss where in the parameter space one might find a precessing signal. This work resulted in a paper submitted to PRD (arXiv:2509.10628). I am currently working on understanding the implications of nutation of the orbit on the GW signals. For this, I am building a waveform that incorporates the nutational effects on the GW signals with precession.
Also, I created this app Generic Precession App to visualize the effects of precession on gravitational wave signals.
More to come. Thank you for your patience.