Spin foam models are a non-perturbative, background independent approach to quantum gravity derived from general relativity formulated as a constrained topological field theory. The sum over histories is codified in group theoretic data associated to a triangulation, which can be understood as area and angle variables. Extracting physics from these models requires efficient numerical...
Within the context of general relativity, black holes must contain a singular core. It is widely believed that singularities are not truly a physical feature, but rather a sign indicating the breakdown of the general relativistic description. Among the possible non-singular scenarios, regular black holes and or horizonless ultracompact stars have taken a particular preeminence. In this talk, I...
Kerr-NUT-AdS spacetimes possess hidden symmetries encoded in the so-called principal Killing-Yano tensor. Focusing on 4 dimensions, we present a number of symmetry operators for scalar, vector, and tensor perturbations, that are of degree 2 (to be defined) and homogeneous in the principal tensor.
Binary compact object mergers are the result of typically tens to hundreds of million years of evolution. Such evolution follows specific pathways, the details of which at current state-of-art are not yet completely understood. These gaps in our understanding are expected to leave residual ambiguities in the prediction of the astrophysical merger rate which can potentially turns out to bias...
In recent years, a mysterious new class of astrophysical objects has been uncovered. These objects are spatially coincident with the nuclei of external galaxies and exhibit X-ray variations that repeat over timescales ranging from minutes to months. They manifest in three distinct ways in the data: stable quasi-periodic oscillations (QPOs), quasi-periodic eruptions (QPEs), and quasi-periodic...
We investigate accretion flows around rotating black holes (BHs) and obtain self-consistent transonic solutions in full general relativistic prescription. The flow is assumed to be viscous and radiative. Viscosity helps in the removal of angular momentum outwards, allowing matter to get accreted inwards. In addition, viscous heat dissipated makes the matter hotter. On the other hand, radiation...
Teukolsky equation allows the study of perturbations of the Kerr metric in linear approximation. We shall discuss how the solution of this equation can be used to compute the evolution of an extreme mass ratio inspiral, where a stellar compact object inspirals towards a supermassive black hole due to gravitational radiation reaction. We will address both time domain and frequency domain...
The effective-one-body (EOB) approach is a powerful formalism that maps the two-body problem in general relativity into the motion of a single body in an effective metric. EOB-based waveform models are nowadays providing fast and accurate templates for comparable-mass coalescing compact binaries, where the latter are the events observed by the currently operating detectors. Third-generation...
Self Force Analytical computations has been used in the past years as an useful tool to calibrate the numerical simulations of waveforms for EMRIs. At the same time, in the field of Scattering Amplitudes, a lot of parallel work has been done in trying to compute observables related to the unbound two-bodies scattering. It has also emerged a theoretical argument that shows how it is possible to...
Conventional searches for gravitational wave signals in detector data are computationally demanding and struggle when certain transient noise sources are present. Recently, machine-learning algorithms have been proposed to address current and future challenges. We present a neural-network based algorithm to search for binary black hole waveforms. We also apply our algorithm to real O3b data...
When a black hole rings due to some external perturbation it emits gravitational waves described by quasi normal modes (QNMs) – a series of exponentially damped harmonic oscillations. If the final state is fully described by the Kerr(-Newman) metric, this ring-down carries a unique signature of its parameters encoded in the modes' complex frequencies. However, astrophysical black holes are...
