The Black Hole Accretion Code
Abstract
We present the black hole accretion code (BHAC), a new multidimensional general-relativistic magnetohydrodynamics module for the MPI-AMRVAC framework. BHAC has been designed to solve the equations of ideal general-relativistic magnetohydrodynamics in arbitrary spacetimes and exploits adaptive mesh refinement techniques with an efficient block-based approach. Several spacetimes have already been implemented and tested. We demonstrate the validity of BHAC by means of various one-, two-, and three-dimensional test problems, as well as through a close comparison with the HARM3D code in the case of a torus accreting onto a black hole. The convergence of a turbulent accretion scenario is investigated with several diagnostics and we find accretion rates and horizon-penetrating fluxes to be convergent to within a few percent when the problem is run in three dimensions. Our analysis also involves the study of the corresponding thermal synchrotron emission, which is performed by means of a new general-relativistic radiative transfer code, BHOSS. The resulting synthetic intensity maps of accretion onto black holes are found to be convergent with increasing resolution and are anticipated to play a crucial role in the interpretation of horizon-scale images resulting from upcoming radio observations of the source at the Galactic Center.
Cite
@article{arxiv.1611.09720,
title = {The Black Hole Accretion Code},
author = {Oliver Porth and Hector Olivares and Yosuke Mizuno and Ziri Younsi and Luciano Rezzolla and Monika Moscibrodzka and Heino Falcke and Michael Kramer},
journal= {arXiv preprint arXiv:1611.09720},
year = {2017}
}
Comments
revised version accepted for publication by Computational Astrophysics and Cosmology. Some figures have been down-sampled