Ricerc@Sapienza

In the last three years the LIGO and Virgo interferometers have detected the gravitational wave (GW) signal emitted from the coalescences of five black hole (BH) binary systems, and one neutron star (NS) binary system, opening a new window onto Einstein's General Relativity (GR) in extreme gravitational settings.

In addition to their impact for astrophysics, GWs are unique probes of fundamental interactions. The aim of this multidisciplinary project is to investigate novel effects related to strong gravitational wave sources -such as BHs and NSs - where matter in extreme conditions, fundamental physics, and the very foundations of GR can be put to the test. We propose to:

i) Test the nature of BHs with GWs
Theoretical arguments suggest that extensions of GR, new fundamental fields, or quantum effects might modify dramatically the formation of BHs. We have recently identified some "smoking guns" that can be used to search for these phenomena with GWs. These include "GW echoes" in the post-merger signal of the coalescence, as well as the absorption of gravitation radiation by the compact object, and their tidal deformability in the late-time inspiral. We will study these effects in full detail, by building precise waveforms to be implemented in GW data analysis.

ii) Constrain the equation of state (EoS) of NSs with GWs
The coalescence of two NSs provides unique information on the behavior of matter in the inner core of the stars, in a regime that is inaccessible by laboratory experiments. Constraining the EoS of NSs from GW observations requires state-of-the-art modelling of the signal and appropriate post-processing strategies which we plan to devise. In addition, we wish to improve current analytical waveforms by including spin effects and higher-order post-Newtonian terms.

Our ultimate goal is to probe fundamental physics in the most extreme gravitational settings and to devise new approaches for detection with current and future GW interferometers.