Radiative Transfer Effects during Photoheating of the Intergalactic Medium

The thermal history of the intergalactic medium (IGM) after reionization is to a large extent determined by photoheating. Here we demonstrate that calculations of the photoheating rate which neglect radiative transfer effects substantially underestimate the energy input during and after reionization. The neglect of radiative transfer effects results in temperatures of the IGM which are too low by a factor of two after HeII reionization. We briefly discuss implications for the absorption properties of the IGM and the distribution of baryons in shallow potential wells.