Research and projects

The final stage of the merging of compact objects is known as the ringdown, and it is described at late times after the signal peak as the superposition of damped sinusoids. This part of the signal is crucial for testing the strong-field regime of gravity and the nature of the remnant object.

 In this work, we performed a novel test of General Relativity (GR) in the ringdown: in particular, we performed a search for additional modes known as scalar-driven modes, arising from beyond-GR theories (first introduced here). We found that no current data support strong evidence for those modes, but future detectors like Einstein Telescope and LISA will be able to observe/constrain them with very good precision! 

In this work, instead, we analyzed the impact of neglecting those modes in a ringdown analysis. Spoiler: you should include them, or you will find non-negligible systematics ;)

If black holes are described by GR, it is known that if two of them interact with each other, they are not deformed. This means that the tidal love number (TLN) is zero. On the flip side, material objects like neutron stars or exotic compact objects (ECOs, here for a review) predict a non-vanishing deformability.

 In this work, we studied how to distinguish between different subsolar (meaning that their mass is below 1 solar mass) compact objects by measuring a putative compact binary of two objects through gravitational waves. We evinced that TLNs can well distinguish between different candidates starting from the ongoing LIGO-Virgo-Kagra fourth observing run. 

Here instead, we analyzed the consequences of the detection of such an event in the cosmology and nuclear physics sectors.

Third-generation detectors such as the Einstein Telescope (ET) will be able to measure with excellent precision the parameters of gravitational waves. However, neglecting effects in the signal, such as the high-order modes of gravitational waves, can induce in systematics that can bias the results. 

In this work, we studied the degeneracy between the distance and the inclination of the source, and we showed that, in the optics of ET, neglecting high-order modes can strongly bias the results.

 Also, as part of the Einstein Telescope Collaboration, I took part in the production of the Blue Book, a science paper for ET. In particular, I took part in some of the works of the Fundamental Physics division group (Div. 1), focusing on testing the nature of compact objects in the inspiral phase.