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

Understand

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.