Radiative Transfer in Smoothed Particle Hydrodynamics Simulations of Cosmological Reionization

We present preliminary results on the incorporation of radiative transfer into the smoothed particle hydrodynamics (SPH) method. SPH is a meshless hydrodynamics method that is widely used in cosmological structure formation simulations. Such simulations achieve relatively high dynamic range and spatial resolution, at a minimum in algorithmic complexity. A key missing ingredient in these simulations is the inclusion of radiation, which accompanies the formation of the first stars and quasars. The radiation from these first stars and quasars had profound effects on the thermal and ionization state of the universe in a complex process known as cosmological reionization. Inclusion of radiative transfer in SPH simulations will allow for simulations which test and constrain the interwoven theories of cosmological reionization and galaxy formation. Here, we concentrate on two methods for transferring radiation, short characteristics (SC) and ray tracing (RT). We explore ways of meshing the particles for the radiative transfer calculation, and present results from tests of the SC and RT methods on a uniform mesh with a central point-source of radiation.

Abstract Author(s): Marcelo Alvarez<br />Paul Shapiro<br />Hugo Martel