A public code for general relativistic, polarised radiative transfer around spinning black holes

By J. Dexter. 2016

156 citations recorded by the source corpus.

Ray tracing radiative transfer is a powerful method for comparing theoretical models of black hole accretion flows and jets with observations. We present a public code, grtrans, for carrying out such calculations in the Kerr metric, including the full treatment of polarised radiative transfer and parallel transport along geodesics. The code is written in Fortran 90 and efficiently parallelises with OpenMP, and the full code and several components have Python interfaces. We describe several tests which are used for verifiying the code, and we compare the results for polarised thin accretion disc and semi-analytic jet problems with those from the literature as examples of its use. Along the way, we provide accurate fitting functions for polarised synchrotron emission and transfer coefficients from thermal and power law distribution functions, and compare results from numerical integration and quadrature solutions of the polarised radiative transfer equations. We also show that all transfer coefficients can play an important role in predicted images and polarisation maps of the Galactic center black hole, Sgr A*, at submillimetre wavelengths.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/64cde0f06b82f0befeb81621aac2c620616a9523

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In Astronomy and Astrophysics

1. R. Genzel
2. L. Tacconi
3. F. Eisenhauer
4. T. Ott
5. N. F. Förster Schreiber
6. A. Eckart
7. S. Gillessen
8. P. Hopkins

Citations in the corpus

• First M87 Event Horizon Telescope Results. VIII. Magnetic Field Structure near The Event Horizon (2021, unknown): “All of the polarimetric images from GRMHD simulations that we analyze in this Letter were generated using the ipole code (Mościbrodzka & Gammie 2018), which has been tested against analytic solutions and numerical ones produced by other numerical GRRT codes (Dexter 2016; Mościbrodzka 2020).”
• IPOLE - semi-analytic scheme for relativistic polarized radiative transport (2017, methodology): “The MNRAS 000, 1–13 (2015) MNRAS 000, 1–13 (2015) exact formulae for emissivity, absorptivity, and rotativity are written down in Dexter (2016) in appendices A1 and B2.”
• Observing the Inner Shadow of a Black Hole: A Direct View of the Event Horizon (2021, methodology): “We also generated images of the 230 GHz and 86 GHz synchrotron emission from this simulation using the GR ray tracing and radiative transfer code grtrans (Dexter 2016).”
• Detection of orbital motions near the last stable circular orbit of the massive black hole SgrA* (2018, background): “In contrast, for a toroidal field configuration, one would expect loops with half the orbital period, Ppol = 0.5 × Porbit, or two loops per orbital period (Bromley et al. 2001; Dexter 2016).”
• Lensing by Kerr black holes (2019, unknown): “Thanks to ray-tracing codes now operating with exquisite accuracy and speed [12–14], determining the observational appearance of a specified emission model is a quick and routine task.”