We release the first Numerical Relativity catalog of Institut de Ciencies del Cosmos at University of Barcelona (ICCUB) consisting of 128 simulations for black hole binaries. All simulations in this first release correspond to highly eccentric binaries with eccentricity ϵ = (0.62, 0.79) which develop zoom-whirls up to three close passages before merger. We consider aligned, equal spin...
Recently, it has been shown that the addition of an infinite tower of higher-curvature terms to the Einstein-Hilbert action in dimensions greater or equal than five regularises the Schwarzschild black hole singularity. In this talk, I will present a dynamical process of thin-shell collapse which leads to the formation of these regular black holes. Starting at some finite radius, the shell...
The thermodynamics of black holes inspired the concept of black hole entropy, linking gravity and thermodynamics. When applied to cosmology, this leads to the standard Friedmann equations, which face challenges in explaining the universe’s evolution. Modified entropies have been proposed to resolve these issues. A recently introduced four-parameter generalized entropy unifies several known...
Extreme-Mass-Ratio Inspirals (EMRIs), consisting of a stellar-mass compact object spiraling into a massive black hole, are key sources of gravitational waves for space-based detectors like LISA. Due to their precise waveforms, EMRIs offer a unique opportunity to test the nature of massive black holes and explore potential deviations from General Relativity, such as non-Kerr geometries. This...
Gravitational waves from stellar-mass binary black hole mergers can come from different formation environments, such as star clusters, active galactic nuclei (AGN) disks, or isolated binary evolution in the field. Some intrinsic characteristics of the gravitational-wave signal, such as eccentricity, spins and phase shifts, can give clues about formation channels. However, some of these...
The precise determination of the current expansion rate of the Universe, the Hubble constant ($H_0$), remains a central challenge in cosmology. To address the persistent $H_0$ tension and reconcile the discrepant values inferred from observations at different redshifts ($z$), we investigate $𝑓(𝑅)$ modified gravity theories in the Jordan frame. In this context, an additional degree of freedom...
