Acoustic horizons in axially symmetric relativistic accretion
Abstract
Transonic accretion onto astrophysical objects is a unique example of analogue black hole realized in nature. In the framework of acoustic geometry we study axially symmetric accretion and wind of a rotating astrophysical black hole or of a neutron star assuming isentropic flow of a fluid described by a polytropic equation of state. In particular we analyze the causal structure of multitransonic configurations with two sonic points and a shock. Retarded and advanced null curves clearly demonstrate the presence of the acoustic black hole at regular sonic points and of the white hole at the shock. We calculate the analogue surface gravity and the Hawking temperature for the inner and the outer acoustic horizons.
Keywords
Cite
@article{arxiv.gr-qc/0509057,
title = {Acoustic horizons in axially symmetric relativistic accretion},
author = {Hrvoje Abraham and Neven Bilic and Tapas K. Das},
journal= {arXiv preprint arXiv:gr-qc/0509057},
year = {2015}
}
Comments
29 pages, 12 figures, significantly revised, sections on phonon propagation, phonon quantization, non-axisymmetric accretion and acoustic superradiance added, references added; to appear in Class. Quant. Grav. without section 2.4 which has been kept here for pedagogical reasons; section 2.4 slightly altered, misprints corrected