# Accretion onto deformed black holes via pseudo-Newtonian potentials

## TL;DR

This paper develops a pseudo-Newtonian potential to study gas accretion onto deformed black holes described by the Johannsen-Psaltis metric, revealing how scalar hair affects accretion rates.

## Contribution

It introduces a generalized potential for accretion analysis around deformed black holes, extending previous models to include scalar hair effects.

## Key findings

- Positive scalar hair increases accretion rate
- Negative scalar hair decreases accretion rate
- Framework adaptable to various astrophysical phenomena

## Abstract

The Johannsen-Psaltis spacetime describes a rotating black hole with parametric deviations from the Kerr metric. By construction this spacetime explicitly violates the no-hair theorems. Rotating black hole solutions in any modified theory of gravity could be written in terms of the Johannsen-Psaltis metric. We examined the accretion of gas onto a black hole described by the static limit of this spacetime. We employed a potential that generalises the Paczynski-Wiita potential to the static Johannsen-Psaltis metric. Our analysis utilised a recent pseudo-Newtonian formulation of the dynamics around arbitrary static, spherically symmetric spacetimes. We found that positive (negative) values of the scalar hair parameter, $\epsilon_{3}$ increased (decreased) the accretion rate. This framework can be extended to incorporate various astrophysical phenomena like radiative processes, viscous dissipation and magnetic fields.