Rates of capture of stars by supermassive black holes in non-spherical galactic nuclei

Abstract

We consider the problem of star consumption by supermassive black holes in non-spherical (axisymmetric, triaxial) galactic nuclei. We review the previous studies of the loss-cone problem and present a novel simulation method which allows to separate out the collisional (relaxation-related) and collisionless (related to non-conservation of angular momentum) processes and determine their relative importance for the capture rates in different geometries. We show that for black holes more massive than 10^7 Msun, the enhancement of capture rate in non-spherical galaxies is substantial, with even modest triaxiality being capable of keeping the capture rate at the level of few percent of black hole mass per Hubble time.