According to the no-hair theorem, quasi-normal mode frequencies and damping times are exclusively determined by a black hole's mass and spin. Black hole spectroscopy has shifted from theoretical conjecture to an empirical method for testing these assumptions using current LIGO-Virgo-Kagra observations. We employ a time-domain analysis in an agnostic framework to identify multiple ringdown...
Motivated by the quantum description of gauge theories, we study the phenomenological effects of relaxing the Hamiltonian and momentum constraints in general relativity. We show that the unconstrained theory has new source terms that mimic a pressureless dust that only follows geodesics. The source term may be the simplest explanation for dark matter and generically predicts a charged...
Compact objects are usually described using the perfect fluid formalism. However, in astrophysical processes out of local equilibrium, dissipative effects become important to realistically describe the dynamics of the system.
In this work, we present for the first time the gauge-invariant non-spherical perturbations in a dissipative self-gravitating fluid in spherical symmetry. For this we...
We have studied the stability of wormhole geometries, under massless scalar, electromagnetic, and axial gravitational perturbations, in the context of higher dimensional spacetimes. Intriguingly, the construction of a wormhole spacetime in the presence of higher dimensions, known as braneworld wormholes, does not require the existence of exotic matter fields, unlike the scenario in four...
We present a forecast for the upcoming Einstein Telescope (ET) interferometer with two new methods to infer cosmological parameters. We consider the emission of Gravitational Waves (GWs) from compact binary coalescences, whose electromagnetic counterpart is missing, namely Dark Sirens events. Most of the methods used to infer cosmological information from GW observations rely on the...
In this talk, we present a method to study the properties of ultra-compact, horizonless objects starting from their scattering properties in terms of an inverse problem. The method is based on a combined inversion of Gamow's formula and the Bohr-Sommerfeld rule. Since the direct measurements of transmission and reflection coefficients of astrophysical compact objects are not available from...
Amplitudes of quasi-normal modes in the gravitational-wave signal emitted during the ringdown phase of a binary black-hole merger provide valuable insights into the strong-field non-linear dynamics of the pre-merger phase. While several studies have modeled mode amplitudes for spin-aligned sources, the more complex scenario of precessing sources has received less attention. In this work, we...
The resonant modes of a black hole consist of damped sinusoids, called quasinormal modes. Due to the dissipative nature of the system, the equation governing the modes is non-hermitian. Nevertheless, quasinormal modes have been shown to be orthogonal with respect to a suitable bilinear form defined in Green et al. (2022).
More recently, Cannizzaro et al. (2023) showed that this bilinear form...
In this seminar, we investigate the topic of gravitational waves in the context of Einstein-Cartan theory by exploiting the Blanchet-Damour formalism.
Einstein-Cartan model has been formulated to extend the concepts of general relativity to the microphysical realm in order to establish a connection between gravity and the other fundamental interactions. In this framework, the quantum...
We explore the phenomenological consequences of breaking discrete global symmetries in quantum gravity (QG). We explore how quantum gravity effects, manifested through the breaking of discrete symmetry responsible for the production of primordial black holes (PBH) resulting from Domain Wall annihilations, can have observational effects through gravitational waves. While stable PBHs formed in...
Solutions to Einstein’s field equations (EFEs) are useful in describing compact stellar objects which have very strong gravitational fields and high densities. Finding these solutions is difficult in general because they are a system of complicated nonlinear partial differential equations. Ad hoc methods need to be employed to make them simpler to work with such as assuming a type of symmetry,...
This presentation delves into the study of 'hairy' black holes within the framework of Einstein scalar Maxwell gravity and Einstein scalar Gauss-Bonnet theories, with a focus on revealing new scalarized black hole solutions. We revisit established scalarization phenomena and venture into new solution territories, particularly highlighting the blend of linear and non-linear scalarization in...
