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}
}
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

Figures from this paper

Can we distinguish black holes from naked singularities by the images of their accretion disks?
We study here images of thin accretion disks around black holes and two classes of naked singularity spacetimes and compare these scenarios. The naked singularity models which have photon spheresExpand
Distinguishing black holes and naked singularities with iron line spectroscopy
It is commonly thought that the final product of gravitational collapse is a black hole. Nevertheless, theoretical studies have not yet provided a final answer to the question whether black holes areExpand
Bound orbits near scalar field naked singularities
We study bound orbits near the centres of static, spherically symmetric, asymptotically flat configurations of a self-gravitating scalar field minimally coupled to gravity. In our approach, aExpand
Towards an observational test of black hole versus naked singularity at the galactic center
While the event horizon of a black hole could cast a shadow that was observed recently, a central singularity without horizon could also give rise to such a feature. This leaves us with a question onExpand
Kα iron line profile from accretion disks around regular and singular exotic compact objects
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
Image of the Janis-Newman-Winicour naked singularity with a thin accretion disk
We study the optical appearance and the apparent radiation flux of a geometrically thin and optically thick accretion disk around the static Janis-Newman-Winicour naked singularity. We confineExpand
Black holes and naked singularities from Anton–Schmidt’s fluids
Abstract Adopting the Tolman–Oppenheimer–Volkoff formalism, we propose a new analytical solution for a static and spherically symmetric black hole where the cosmological constant is generalized to aExpand
Shadows of spherically symmetric black holes and naked singularities
We compare shadows cast by Schwarzschild black holes with those produced by two classes of naked singularities that result from gravitational collapse of spherically symmetric matter. The latterExpand
Structure of the thin disk in the background of a distorted naked singularity versus a distorted static black hole
We consider the standard relativistic geometrically thin and optically thick accretion disc around a distorted static black hole and a distorted naked singularity. The distortion is the result of theExpand
Circular orbits in Kerr-Taub-NUT spacetime and their implications for accreting black holes and naked singularities
It has recently been proposed that the accreting collapsed object GRO J1655--40 could contain a non-zero gravitomagnetic monopole, and hence could be better described with the more generalExpand
...
1
2
3
4
5
...

References

SHOWING 1-10 OF 81 REFERENCES
Can accretion disk properties observationally distinguish black holes from naked singularities
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
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
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
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
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
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
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
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
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
...
1
2
3
4
5
...