Self-similar scalar field collapse

Banerjee, Narayan; Chakrabarti, Soumya

doi:10.1103/physrevd.95.024015

Cited by 31 publications

(22 citation statements)

References 59 publications

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“…, the first term in the right hand side of the above expression dominates. Only when β < 0, the condition (28), obtained using the Raychaudhuri equation, is fulfilled in this region and a singularity within finite z is unavoidable. On the other hand if β > 0, a dispersal will occur in this region.…”

Section: Exact Solutions and The Raychaudhuri Equationmentioning

confidence: 98%

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Self similar collapse and the Raychaudhuri equation

Choudhury¹,

Chakrabarti²,

Dasgupta³

et al. 2019

Eur. Phys. J. C

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The role of the Raychaudhuri equation in studying gravitational collapse is discussed. A self-similar distribution of a scalar field along with an imperfect fluid in a conformally flat spacetime is considered for the purpose. The general focusing condition is found out and verified against the available exact solutions. The connection between the Raychaudhuri equation and the critical phenomena is also explored.

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Section: Exact Solutions and The Raychaudhuri Equationmentioning

confidence: 98%

“…These generic conditions like (28) or (29), may appear useful. These are generic conditions if satisfied by the conformal factor or the energy momentum tensor components, will lead to the formation of a singularity.…”

Section: Raychaudhuri Equation and The Dynamics Of Spacetimementioning

confidence: 99%

Self similar collapse and the Raychaudhuri equation

Choudhury¹,

Chakrabarti²,

Dasgupta³

et al. 2019

Eur. Phys. J. C

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“…The scope of this approach in gravitational physics has been studied only very recently, for example, in massive scalar field collapse [55,56] and Scalar-Einstein-Gauss-Bonnet gravity [57], cosmological reconstruction of modified theories of gravity [58,59].…”

Section: Integrability Of Anharmonic Oscillator Equationsmentioning

confidence: 99%

Exact solutions and accelerating universe in modified Brans–Dicke theories

Mukherjee

Chakrabarti

2019

Eur. Phys. J. C

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Exact solutions are studied in the context of modified Brans-Dicke theory. The non-linearity of the modified Brans-Dicke field equations is treated with the Euler-Duarte-Moreira method of integrability of anharmonic oscillator equation. While some solutions show a forever accelerating nature, in some cases there is a signature flip in the evolution of deceleration parameter in recent past. Importance of these latter models are studied in the context of late time acceleration of the universe. Constraints on the model parameters are obtained from Markov Chain Monte Carlo (MCMC) analysis using the Supernova distance modulus data, observational measurements of Hubble parameter, Baryon acoustic oscillation data and the CMB Shift parameter data.

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“…Though forbidden by the cosmic censorship conjecture [16], naked singularities can form as an end-state of gravitational collapse of massive matter clouds under suitable initial conditions [17][18][19][20][21][22][23][24][25][26][27][28][29]. An inevitable question that now arises is how to observationally distinguish such naked singularities from a black hole spacetime.…”

Section: Introductionmentioning

confidence: 99%

Echoes from a singularity

Chowdhury,

Banerjee

2020

Preprint

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Though the cosmic censorship conjecture states that spacetime singularities must be hidden from an asymptotic observer by an event horizon, naked singularities can form as the end product of a gravitational collapse under quite general initial conditions. So the question of how to observationally distinguish such naked singularities from standard black hole spacetimes becomes important. In the present paper, we try to address this question by studying the ringdown profile of the Janis-Newman-Winicour (JNW) naked singularity under axial gravitational perturbation. The JNW spacetime has a surface-like naked singularity that is sourced by a massless scalar field and reduces to the Schwarzschild solution in absence of the scalar field. We show that for low strength of the scalar field, the ringdown profile is dominated by echoes which mellows down as the strength of the field increases to yield characteristic quasinormal frequency of the JNW spacetime.

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Self-similar scalar field collapse

Cited by 31 publications

References 59 publications

Self similar collapse and the Raychaudhuri equation

Self similar collapse and the Raychaudhuri equation

Exact solutions and accelerating universe in modified Brans–Dicke theories

Echoes from a singularity

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