April 10, 2024

Repeating partial disruptions and two-body relaxation

Broggi, Luca; Stone, Nicholas C.; Ryu, Taeho; Bortolas, Elisa; Dotti, Massimo; Bonetti, Matteo; Sesana, Alberto Two-body relaxation may drive stars onto near-radial orbits around a massive black hole, resulting in a tidal disruption event (TDE). In some circumstances, stars are unlikely to undergo a single terminal disruption, but rather to have a sequence of many grazing encounters with the black hole. It has long been unclear what is the physical outcome of this sequence: each of these encounters can only liberate a small amount of stellar mass, but may significantly alter the orbit of the star.

December 20, 2023

Demographics of Tidal Disruption Events with L-Galaxies: I. Volumetric TDE rates and the abundance of Nuclear Star Clusters

Polkas, Markos; Bonoli, Silvia; Bortolas, Elisa; Izquierdo-Villalba, David; Sesana, Alberto; Broggi, Luca; Hoyer, Nils; Spinoso, Daniele Stars can be ripped apart by tidal forces in the vicinity of a massive black hole, causing luminous flares classified as tidal disruption events (TDEs). These events could be contributing to the mass growth of intermediate-mass black holes, while new samples from ongoing transient surveys can provide useful information on this unexplored growth channel.

March 24, 2023

Gravitational waves from an eccentric population of primordial black holes orbiting Sgr A⋆

Bondani, Stefano; Bonetti, Matteo; Broggi, Luca; Haardt, Francesco; Sesana, Alberto; Dotti, Massimo. Primordial black holes (PBH), supposedly formed in the very early Universe, have been proposed as a possible viable dark matter candidate. In this work we characterize the expected gravitational wave (GW) losses from a population of PBHs orbiting Sgr A⋆, the super-massive black hole at the Galactic center, and assess the signal detectability by the planned space-borne interferometer LISA and by the proposed next generation space-borne interferometer μAres.