Among the most interesting gravitational waves sources are coalescing neutron star and black hole binaries during the last few minutes in their lifetime. The binary’s orbit gradually shrinks due to gravitational wave losses, leading to an adiabatic inspiral until the two objects merge to form a perturbed remnant black hole, emitting oscillatory GW with several hundreds to thousands of cycles during the entire process.
Extracting these signals from the detector noise and measuring their parameters will rely on matched filtering, where the datastream is cross-correlated with a bank of theoretical waveform templates and the template parameters are varied to maximize the overlap. This is similar to doing a Fourier transform but with more complicated basis functions than just sines and cosines. To maximize the science payoffs, the templates must achieve a phasing accuracy of better than one radian over entire signal duration. Moreover, they must be sufficiently cheap to generate that they cover the entire physical
parameter space. Meeting these criteria presents a significant theoretical challenge.
Accurate waveforms could in principle be obtained with numerical relativity simulations, where Einstein's equations are solved numerically on supercomputer clusters. However, their considerable computational costs make them impractical for generating an entire template bank. There is thus an urgent need for analytical models which are computationally efficient and include all effects that might lead to a measurable phase perturbation. My research on modeling the dynamics and gravitational waves from binary systems is part of the effort to address this challenge.
The main focus of my work has been on the following topics:
- The effects of neutron star matter on the gravitational waves: information on their ultra dense interiors, see here for more information
- Strong-gravity effects in the inspirals of small mass objects into a supermassive black hole in the center of a galaxy: systematic analytical approximation method for a longterm description and analysis oftransient resonances, see here for more information
- Testing analytical models against numerical relativity simulations: the gauge invariant periastron advance for binaries with spins (read the article here) and an improved full waveform model (read the short paper here).
- Improving the modeling of spin effects for black hole binaries in post-Newtonian theory: spin effects in the full waveform modes at 2nd post-Newtonian order (read the article here)
I am also interested in other topics in relativity that are not directly related to gravitational waves:
- Colliding black holes at high energy: analytical estimates for scattering thresholds, and gravitational radiation (read the paper here); the short paper focusing on the numerical relativity results from our collaborators can be found here
- Axisymmetric dynamical spacetimes (read the paper here)