# Distinguishing black holes from naked singularities through their accretion disc properties

@article{Joshi2014DistinguishingBH,
title={Distinguishing black holes from naked singularities through their accretion disc properties},
author={Pankaj S. Joshi and Daniele Malafarina and Ramesh Narayan},
journal={Classical and Quantum Gravity},
year={2014},
volume={31},
pages={015002}
}
• Published 2014
• Physics
• Classical and Quantum Gravity
We show that, in principle, a slowly evolving gravitationally collapsing perfect fluid cloud can asymptotically settle to a static spherically symmetric equilibrium configuration with a naked singularity at the center. We consider one such asymptotic final configuration with a finite outer radius, and construct a toy model in which it is matched to a Schwarzschild exterior geometry. We examine the properties of circular orbits in this model. We then investigate the observational signatures of a… Expand

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#### References

SHOWING 1-10 OF 81 REFERENCES
Can accretion disk properties observationally distinguish black holes from naked singularities
• Physics
• 2010
Naked singularities are hypothetical astrophysical objects, characterized by a gravitational singularity without an event horizon. Penrose has proposed a conjecture, according to which there exists aExpand
Accretion disc onto a static non-baryonic compact object
Abstract We study the emissivity properties of a geometrically thin, optically thick, steady accretion disc about a static boson star. Starting from a numerical computation of the metric potentialsExpand
Kα iron line profile from accretion disks around regular and singular exotic compact objects
• Physics
• 2013
The nature of the super-massive black hole candidates in galactic nuclei can be tested by analyzing the profile of the K$\alpha$ iron line observed in their X-ray spectrum. In this paper, we considerExpand
Equilibrium configurations from gravitational collapse
• Physics
• 2011
We develop here a new procedure within Einstein’s theory of gravity to generate equilibrium configurations that result as the final state of gravitational collapse from regular initial conditions. AsExpand
Appearance of Keplerian discs orbiting Kerr superspinars
• Physics
• 2010
We study optical phenomena related to the appearance of Keplerian accretion discs orbiting Kerr superspinars predicted by string theory. The superspinar exterior is described by standard Kerr nakedExpand
Recent developments in gravitational collapse and spacetime singularities
• Physics
• 2011
It is now known that when a massive star collapses under the force of its own gravity, the final fate of such a continual gravitational collapse will be either a black hole or a naked singularityExpand
Gravitational collapse in asymptotically anti de Sitter or de Sitter backgrounds
• Physics
• 2005
We study here the gravitational collapse of a matter cloud with a nonvanishing tangential pressure in the presence of a nonzero cosmological term {lambda}. It is investigated how {lambda} modifiesExpand
The Event Horizon of Sagittarius A
• Physics
• 2009
Black hole event horizons, causally separating the external universe from compact regions of spacetime, are one of the most exotic predictions of general relativity. Until recently, their compactExpand
Equatorial circular motion in Kerr spacetime
• Physics
• 2011
We analyze the properties of circular orbits of test particles on the equatorial plane of a rotating central mass whose gravitational eld is described by the Kerr spacetime. For rotating black holesExpand
Advection-Dominated Accretion and the Black Hole Event Horizon
• Physics
• 2008
Abstract As the luminosity of an accreting black hole drops to a few percent of Eddington, the spectrum switches from the familiar soft state to a hard state that is well-described by a distended andExpand