Accretion disks around naked singularities

TL;DR

This paper studies the thermal properties and luminosity profiles of accretion disks around naked singularities with various density profiles, revealing potential observational differences from black holes.

Contribution

It introduces a detailed analysis of accretion disks around naked singularities, highlighting how their luminosity and efficiency differ from black holes based on matter density profiles.

Findings

Accretion disks around naked singularities can have higher luminosities than those around black holes.

Luminosity distribution slopes differ significantly at higher frequencies, aiding in distinguishing naked singularities from black holes.

The strength of the singularity correlates with the efficiency of accretion, with stronger singularities yielding higher efficiencies.

Abstract

We investigate here the thermal properties of accretion disks in a spacetime for some galactic density profiles in spherical symmetry. The matter distributions have a finite outer radius with a naked central singularity. The luminosities of the accretion disks for some density profile models are found to be higher than those for a Schwarzschild black hole of the same mass. The slopes for the luminosity distributions with respect to frequencies are significantly different, especially at higher frequencies, from that in the Schwarzschild black hole case. Such features may be used to distinguish black holes from naked singularities. The efficiencies for the conversion of the mass energy of the accreting gas into radiation and the strength of naked singularities are analyzed. The novel feature that we find is, the strength of the singularity is different depending on the profiles considered, and the stronger the singularity is, the higher is the efficiency for the accretion disk.