Compact Objects

Our research on compact objects focuses on the most extreme objects in the universe: black holes, neutron stars, and exotic compact objects. We study their formation, dynamics, mergers, and the gravitational waves they emit.

Eccentric Binary Black Hole (BBH) Mergers

The majority of detected BBH mergers exhibit circular orbits, but some binaries formed in dense stellar clusters or galactic nuclei can have measurable eccentricity. The detection of such mergers provides crucial information about their formation channels. With O4 and O5 expected to significantly increase the number of detected eccentric BBH mergers, this project aims to refine waveform models by testing and calibrating the TEOBResumS framework using numerical relativity (NR) simulations. The goal is to improve parameter estimation and waveform templates for future observations.

Binary Neutron Star (BNS) Mergers and Post-Merger Remnants

The landmark detection of GW170817 confirmed that BNS mergers are the progenitors of short gamma-ray bursts (GRBs) and kilonovae, and provided new constraints on the equation of state (EOS) of neutron stars. This project focuses on post-merger physics, particularly the role of magnetic-field amplification and finite-temperature effects in hypermassive neutron stars (HMNS). Advanced numerical simulations will be performed using the Einstein Toolkit, incorporating the newly developed MInIT turbulence model to study angular momentum transport in the HMNS. These studies will improve our understanding of post-merger GW emission and may provide observational signatures for future GW detectors.

Proto-Neutron Star (PNS) Oscillations and Asteroseismology

During core-collapse supernovae (CCSN), the proto-neutron star (PNS) undergoes oscillations that generate GWs in the 10-5000 Hz range. If detected, these signals could provide direct information on the internal structure of neutron stars and the dynamics of supernova explosions. This project builds on previous work by the group, which developed numerical methods to analyze the eigenmodes of oscillating PNSs and established universal relations linking GW frequencies to the mass and radius of the PNS. The project will refine these techniques, extend them to rotating progenitors, and explore the detectability of inertial modes using Bayesian inference.

GWs from Exotic Compact Objects (ECOs)

GW observations provide a unique tool to test alternative theories of gravity and explore new physics beyond the Standard Model. This research investigates the possibility that some observed GW signals originate from exotic compact objects (ECOs) such as boson stars or black holes with bosonic hair, which could provide insights into dark matter. The team will conduct NR simulations of ECO mergers, construct waveform catalogs, and perform parameter estimation on LVK events to determine whether any detected signals deviate from the predictions of classical black hole mergers. A particularly intriguing case study is GW190521, which has been hypothesized to result from the merger of Proca stars.