HEROIC: 3D general relativistic radiative post-processor with comptonization for black hole accretion discs

Ramesh Narayan, Yucong Zhu, Dimitrios Psaltis, Aleksander Sadowski

Research output: Contribution to journalArticle

25 Scopus citations

Abstract

We describe Hybrid Evaluator for Radiative Objects Including Comptonization (HEROIC), an upgraded version of the relativistic radiative post-processor code HERO described in a previous paper, but which now Includes Comptonization. HEROIC models Comptonization via the Kompaneets equation, using a quadratic approximation for the source function in a short characteristics radiation solver. It employs a simple form of accelerated lambda iteration to handle regions of high scattering opacity. In addition to solving for the radiation field, HEROIC also solves for the gas temperature by applying the condition of radiative equilibrium. We present benchmarks and tests of the Comptonization module in HEROIC with simple 1D and 3D scattering problems. We also test the ability of the code to handle various relativistic effects using model atmospheres and accretion flows in a black hole space-time. We present two applications of HEROIC to general relativistic magnetohydrodynamics simulations of accretion discs. One application is to a thin accretion disc around a black hole.We find that the gas below the photosphere in the multidimensional HEROIC solution is nearly isothermal, quite different from previous solutions based on 1D plane parallel atmospheres. The second application is to a geometrically thick radiation-dominated accretion disc accreting at 11 times the Eddington rate. Here, the multidimensional HEROIC solution shows that, for observers who are on axis and look down the polar funnel, the isotropic equivalent luminosity could be more than 10 times the Eddington limit, even though the spectrum might still look thermal and show no signs of relativistic beaming.

Original languageEnglish (US)
Pages (from-to)608-628
Number of pages21
JournalMonthly Notices of the Royal Astronomical Society
Volume457
Issue number1
DOIs
StatePublished - Jan 11 2016

Keywords

  • Accretion
  • Accretion discs
  • Black hole physics
  • Galaxies: nuclei
  • MHD
  • Radiative transfer
  • Stars: black holes

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

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