Image of the Janis-Newman-Winicour naked singularity with a thin accretion disk
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.
Keywords
Cite
@article{arxiv.1905.05273,
title = {Image of the Janis-Newman-Winicour naked singularity with a thin accretion disk},
author = {Galin Gyulchev and Petya Nedkova and Tsvetan Vetsov and Stoytcho Yazadjiev},
journal= {arXiv preprint arXiv:1905.05273},
year = {2019}
}
Comments
21 pages; 9 figures