Modelling the uv/x-ray cosmic background with CUBA

TL;DR

This paper introduces the CUBA numerical code for modeling the cosmological UV/X-ray background, incorporating observed populations of QSOs and star-forming galaxies, and presents new results on background evolution and ionization states.

Contribution

The paper presents the CUBA code for solving radiative transfer in cosmology and provides new UV/X-ray background results based on observed galaxy and QSO populations.

Findings

Updated UV/X-ray background models from observed populations.

Derived ionization and thermal states of the intergalactic medium.

Analysis of HeII opacity and ionization rates.

Abstract

In this paper, I will describe the features of the numerical code CUBA, aimed at the solution of the radiative transfer equation in a cosmological context. CUBA will be soon available for public use at the URL http://pitto.mib.infn.it/~haardt/, allowing for several user-supplied input parameters, such as favourite cosmology, luminosity functions, Type II object evolution, stellar spectra, and many others. I will also present some new results of the UV/X-ray cosmic background as produced by the observed populations of QSOs and star forming galaxies, updating and extending our previous works. The background evolution is complemented with a number of derived quantities such as the ionization and thermal state of the IGM, the HeII opacity, the HI and HeII ionization rates, and the HI, HeII and Compton heating rates.