### 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 language | English (US) |
---|---|

Pages (from-to) | 608-628 |

Number of pages | 21 |

Journal | Monthly Notices of the Royal Astronomical Society |

Volume | 457 |

Issue number | 1 |

DOIs | |

State | Published - Jan 11 2016 |

### Fingerprint

### 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

### Cite this

*Monthly Notices of the Royal Astronomical Society*,

*457*(1), 608-628. https://doi.org/10.1093/mnras/stv2979

**HEROIC : 3D general relativistic radiative post-processor with comptonization for black hole accretion discs.** / Narayan, Ramesh; Zhu, Yucong; Psaltis, Dimitrios; Sadowski, Aleksander.

Research output: Contribution to journal › Article

*Monthly Notices of the Royal Astronomical Society*, vol. 457, no. 1, pp. 608-628. https://doi.org/10.1093/mnras/stv2979

}

TY - JOUR

T1 - HEROIC

T2 - 3D general relativistic radiative post-processor with comptonization for black hole accretion discs

AU - Narayan, Ramesh

AU - Zhu, Yucong

AU - Psaltis, Dimitrios

AU - Sadowski, Aleksander

PY - 2016/1/11

Y1 - 2016/1/11

N2 - 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.

AB - 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.

KW - Accretion

KW - Accretion discs

KW - Black hole physics

KW - Galaxies: nuclei

KW - MHD

KW - Radiative transfer

KW - Stars: black holes

UR - http://www.scopus.com/inward/record.url?scp=84961634121&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84961634121&partnerID=8YFLogxK

U2 - 10.1093/mnras/stv2979

DO - 10.1093/mnras/stv2979

M3 - Article

AN - SCOPUS:84961634121

VL - 457

SP - 608

EP - 628

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

IS - 1

ER -