Echoes from a singularity

Abstract

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 suitable 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 surfacelike 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 mode frequency of the JNW spacetime.

Version published in PRD

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Cited by in corpus (6)

• Horizon-scale tests of gravity theories and fundamental physics from the Event Horizon Telescope image of Sagittarius A${}^{\ast }$
• Probing hairy black holes caused by gravitational decoupling using quasinormal modes and greybody bounds
• Ringing of a black hole in a dark matter halo
• Echoes from Classical Black Holes
• The Raychaudhuri equation for a quantized timelike geodesic congruence
• Naked singularity in 4D Einstein-Gauss-Bonnet novel gravity: Echoes and (in)-stability