Speaker
Description
We report on the increase in irreducible mass resulting from a particle’s plunge along the inner most stable circular orbit (ISCO) into a black hole (BH), examining both cases: the conservative approximation and with gravitational wave (GW) radiation; the former corresponds to BH accretion, and the latter to extreme mass-ratio inspirals (EMRIs). For prograde orbits, we find that the ratio of mass change to irreducible mass change is lower when GW radiation is taken into account than in the conservative case, while the opposite holds for retrograde orbits. Based on the differentiating changes in mass and irreducible mass, which are non-monotonic with respect to the spin, we derive the increasing curves of mass and irreducible mass. In the conservative case, after accreting up to three times its initial mass, the BH’s spin parameter reaches the extremal value $\hat{a} = 1$ and then enters a self-similar growth phase. When GW radiation is considered, however, the spin parameter does not reach the extremal limit but instead stabilizes near it. For the first time, we precisely determine this stabilization value and fit an analytical expression relating this stable value to the mass ratio.