Rabacus: A Python Package for Analytic Cosmological Radiative Transfer Calculations

TL;DR

Rabacus is a Python package that efficiently models hydrogen and helium ionizing radiation transfer in simplified cosmological geometries, supporting arbitrary spectra and density profiles with self-consistent temperature and recombination radiation calculations.

Contribution

It introduces a fast, versatile Python tool for analytic cosmological radiative transfer calculations with self-consistent temperature and radiation treatment.

Findings

Fast execution speeds due to Fortran 90 core routines

Supports arbitrary spectra and density profiles

Includes self-consistent temperature and recombination radiation calculations

Abstract

We describe Rabacus, a Python package for calculating the transfer of hydrogen ionizing radiation in simplified geometries relevant to astronomy and cosmology. We present example solutions for three specific cases: 1) a semi-infinite slab gas distribution in a homogeneous isotropic background, 2) a spherically symmetric gas distribution with a point source at the center, and 3) a spherically symmetric gas distribution in a homogeneous isotropic background. All problems can accommodate arbitrary spectra and density profiles as input. The solutions include a treatment of both hydrogen and helium, a self-consistent calculation of equilibrium temperatures, and the transfer of recombination radiation. The core routines are written in Fortran 90 and then wrapped in Python leading to execution speeds thousands of times faster than equivalent routines written in pure Python. In addition, all variables have associated units for ease of analysis. The software is part of the Python Package Index and the source code is available on Bitbucket at https://bitbucket.org/galtay/rabacus . In addition, installation instructions and a detailed users guide are available at http://pythonhosted.org//rabacus .