Speaker
Mr
Michele Compostella
(Argelander Institute for Astronomy, Bonn)
Description
I will present results on the topology of HeII reionization obtained from AMR hydrodynamic simulations of the intergalactic medium post-processed with the radiative transfer code RADAMESH. Ionizing radiation is propagated from a realistic population of active galactic nuclei considering different scenarios for the time evolution of the ionizing sources. During the early phases of the reionization the temperature distribution presents a clear bimodality and cannot be described by a simple effective equation of state. When helium reionization is complete, the IGM is characterized by a polytropic equation of state appreciably flatter than at the onset of the reionization process, with a wider dispersion around the mean value. By extracting synthetic Lyα absorption spectra from the simulations, I will provide evidence that the Doppler b parameters and the curvature statistics of HI absorption spectra contain information about the bimodal temperature distribution of the IGM during the early phases of HeII reionization.
