A mechanism for a "leaky" black hole to catalyze galaxy formation

TL;DR

This paper proposes a novel mechanism where a black hole's gravitational effects facilitate galaxy formation by enabling particle collisions that lead to star creation, explaining certain galaxy brightness profiles.

Contribution

It introduces a new black hole-driven process for galaxy formation, linking particle collisions near black holes to star nucleation and galaxy structure.

Findings

Collision products have zero radial velocity at certain radii.

The mechanism explains exponential brightness profiles in disk galaxies.

Provides estimates for galaxy scale lengths based on black hole effects.

Abstract

In the gravitational field of a Schwarzschild-like black hole, particles infalling from rest at infinity, and black hole "wind" particles with relativistic velocity leaking radially out from the nominal horizon, both have the same magnitude of velocity at any radius from the hole. Hence when equally massive infalling and wind particles collide at any radius, they yield collision products with zero center of mass radial velocity, which can then nucleate star formation at the collision radius. We suggest that this gives a mechanism by which a central black hole can catalyze galaxy formation. For disk galaxies, this mechanism explains the observed approximately exponential falloff of the surface brightness with radius, and gives an estimate of the associated scale length.