2016/02/09 by Jason Dexter · 192 citations
Physics and Astronomy · #Active galactic nucleus #Astrophysical Phenomena and Observations #Astrophysics #Black hole (networking) #Computational physics #Fortran #Galaxy #Geodesic #Geometry #Optics #Physics #Python (programming language) #Radiative cooling #Radiative transfer #astro-ph.HE
paper · pdf · doi:10.1093/mnras/stw1526
published in Monthly Notices of the Royal Astronomical Society 462(1), 115-136 (Oxford University Press) · 22 pages, 12 figures, submitted to MNRAS. code available at: github.com/jadexter/grtrans
arxiv created 2016/02/09 · openalex publication_date 2016/06/26 · arxiv updated 2016/09/07 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
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 centre black hole, Sgr A*, at submillimetre wavelengths.