Broggi, Luca In this letter, we present a new formulation of loss cone theory as a reaction-diffusion system, which is orbit averaged and accounts for loss cone events through a sink term. This formulation can recover the standard approach based on boundary conditions, and is derived from a simple physical model that overcomes many of the classical theoretical constraints. The relaxed distribution of disruptive orbits in phase space has a simple analytic form, and it predicts accurately the pericentre of tidal disruption events at disruption, better than other available formulas.

Mancieri, Davide; Broggi, Luca; Bonetti, Matteo; Sesana, Alberto Extreme mass ratio inspirals (EMRIs) are anticipated to be primary gravitational wave sources for the Laser Interferometer Space Antenna (LISA). They form in dense nuclear clusters, when a compact object is captured by the central massive black holes (MBHs) as a consequence of the frequent two-body interactions occurring between orbiting objects. The physics of this process is complex and requires detailed statistical modeling of a multi-body relativistic system.

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.

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.

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.