Parallel multi-frequency-band cosmological radiative transfer with CRASH4 and applications

Abstract Here we introduce CRASH4 [6], the fourth release of the cosmological radiative transfer code CRASH [1-5]. The code is able to simulate the radiative transfer through H [1] and He [2-3] and cosmic metals polluting the intergalactic medium [5]. Numerical simulations of the hydrogen and helium reionisation processes have already been performed with the previous releases [4-5]; in the new release we focus on advanced parallelisation to handle the RT on large cosmic scales and in multiple, synchronous spectral bands [6]. These advancements will provide a more realistic description of the process of Cosmic Reionisation through metals [5] and line transfer. New techniques of Monte Carlo parallelisation and Big Data management, required by our large scale simulations, are described as well as our scientific goals and results.