The final fate of spherical inhomogeneous dust collapse: II. Initial data and causal structure of the singularity

Jhingan, Sanjay; Joshi, Pankaj S.; Singh, T. P.

doi:10.1088/0264-9381/13/11/019

Cited by 78 publications

(72 citation statements)

References 23 publications

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“…Detailed analysis on the occurrence of naked shell-focusing singularity has been done in [1][2][3][4][29][30][31]. Here we present one of the results.…”

Section: Lemaître-tolman-bondi Solutionmentioning

confidence: 94%

Power, energy, and spectrum of a naked singularity explosion

2000

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It is well known that a naked singularity occurs in the gravitational collapse of an inhomogeneous dust ball from an initial density profile which is physically reasonable. In this paper we show that explosive radiation is emitted during the formation process of the naked singularity while we fix the background spacetime. The energy flux is proportional to (tCH − t) −3/2 for a minimally coupled massless scalar field, while it is proportional to (tCH − t) −1 for a conformally coupled massless scalar field, where tCH − t is the "remaineing time" until the distant observer could observe the singularity if the naked singularity was formed. As a consequence, the radiated energy grows unboundedly for both scalar fields. The amount of the power and energy depends on the parameters which characterize the initial density profile but do not depend on the gravitational mass of the cloud. In particular, there is a characteristic frequency νs of the singularity above which the divergent energy is radiated. The energy flux is dominated by particles of which the wavelength is about tCH − t at each moment. The observed total spectrum is nonthermal, i.e., νdN/dν ∼ (ν/νs) −1 for ν > νs. If the naked singularity formation could continue until a considerable fraction of the total energy of the dust cloud is radiated, the radiated energy would reach about 10 54 (M/M⊙)erg. The calculations are based on the geometrical optics approximation which turns out to be consistent for a rough order estimate. The analysis does not depend on whether or not the naked singularity occurs in its exact meaning. This phenomenon may provide a new candidate for a source of ultrahigh energy cosmic rays or a central engine of γ-ray bursts.

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“…Detailed analysis on the occurrence of naked shell-focusing singularity has been done in [1][2][3][4][29][30][31]. Here we present one of the results.…”

Section: Lemaître-tolman-bondi Solutionmentioning

confidence: 94%

Power, energy, and spectrum of a naked singularity explosion

2000

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“…The nature of singularities in classical LTB collapse, and their dependence on initial data, has been studied in great detail [12], [13], [14]. For some initial data, the LTB collapse ends in a black hole, and for other (generic) initial data it ends in a naked singularity.…”

Section: Introductionmentioning

confidence: 99%

Particle creation in (2+1) circular dust collapse

Gutti

Singh

2007

Phys. Rev. D

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We investigate the quantum particle creation during the circularly symmetric collapse of a 2+1 dust cloud, for the cases when the cosmological constant is either zero or negative. We derive the Ford-Parker formula for the 2+1 case, which can be used to compute the radiated quantum flux in the geometric optics approximation. It is shown that no particles are created when the collapse ends in a naked singularity, unlike in the 3+1 case. When the collapse ends in a BTZ black hole, we recover the expected Hawking radiation.

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“…Eardley and Smarr pointed out that a shell focusing singularity formed at the symmetric center in an inhomogeneous dust sphere can be naked, i.e., visible in principle [6]. After this discovery, several theoretical efforts revealed the genericity of the shell focusing naked singularity formation in the LTB solution [7][8][9][10][11][12]; there are radial null geodesics emanating from the central shell focusing singularity.…”

Section: Introductionmentioning

confidence: 99%

How does a naked singularity look?

2003

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There are non-radial null geodesics emanating from the shell focusing singularity formed at the symmetric center in a spherically symmetric dust collapse.In this article, assuming the self-similarity in the region filled with the dust fluid, we study these singular null geodesics in detail. We see the time evolution of the angular diameter of the central naked singularity and show that it might be bounded above by the value corresponding to the circular null geodesic in the Schwarzschild spacetime. We also investigate the angular frequency of a physical field which propagates along the singular null geodesic and find that it depends on the impact parameter. Further, we comment on the non-uniformity of the topology of the central naked singularity. PACS number(s): 04

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The final fate of spherical inhomogeneous dust collapse: II. Initial data and causal structure of the singularity

Cited by 78 publications

References 23 publications

Power, energy, and spectrum of a naked singularity explosion

Power, energy, and spectrum of a naked singularity explosion

Particle creation in (2+1) circular dust collapse

How does a naked singularity look?

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