Abstract Details

Name: Arun Kenath
Affiliation: Christ University
Conference ID: ASI2020_219
Title : Is the Binding Energy of Galaxies related to their Core Black Hole Mass?
Authors and Co-Authors : Arun Kenath and C. Sivaram
Abstract Type : Oral
Abstract Category : General Relativity and Cosmology
Abstract : Most of the large galaxies host a supermassive black hole, even AGN’s, quasars, etc. are powered by the gravitational energy of matter accreting on to these central supermassive black holes. These black hole masses are typically of several millions of solar masses and can be as large as a few billion solar masses. But their origin is still not well understood. The black hole masses have been related to the galactic bulge mass, suggesting a common origin. Here we propose a possible connection between the gravitational binding energy (BE) of the host galaxy and the mass of the central black hole, similar to what happens in core collapse of massive stars. The gravitational BE released in stellar collapse is carried away by neutrinos mainly (e.g. SN1987A). The total energy carried away is the gravitational BE of the remnant neutron star. In case of galactic structures, the BE of the parent galaxy is comparable to that of the black hole hosted by the galaxy. The BE of a typical galaxy like the Milky Way is of the order of 10^61 ergs, which is same as the energy of the million solar mass black hole harboured by the Milky Way. This is similar to what happens in the release of gravitational BE in stellar collapses leading to the formation of remnant compact objects. Even for large elliptical galaxies, like M87, the BE is of the order of 10^63 ergs, again same as the energy of the billion solar mass black hole harboured by it. Using this model we argue why globular clusters are unlikely to harbour large black holes and why dwarf galaxies, if they have to host black holes, should have observed mass to light ratios of ~100.