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arXiv · 1905.05273

Image of the Janis-Newman-Winicour naked singularity with a thin accretion disk

Galin Gyulchev·Petya Nedkova·Tsvetan Vetsov·Stoytcho Yazadjiev
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Abstract

We study the optical appearance and the apparent radiation flux of a thin accretion disk around the static Janis-Newman-Winicour naked singularity. We confine ourselves to the astrophysically most relevant case, when the solution possesses a photon sphere, assuming that the radiation emitted by the disk is described by the Novikov-Thorne model. The observable images resemble closely the visual appearance of the Schwarzschild black hole, as only quantitative differences are present. For the Janis-Newman-Winicour solution the accretion disk appears smaller, and its emission is characterized by a higher peak of the radiation flux. In addition, the most significant part of the radiation is concentrated in a closer neighbourhood of the flux maximum. The results are obtained independently by two alternative methods, consisting of a semi-analytical scheme using the spherical symmetry of the spacetime, and a fully numerical ray-tracing procedure valid for any stationary and axisymmetric spacetime.

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Galin Gyulchev, Petya Nedkova, Tsvetan Vetsov, Stoytcho Yazadjiev. 2019-05-13. Image of the Janis-Newman-Winicour naked singularity with a thin accretion disk. https://doi.org/10.1103/physrevd.100.024055

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