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P. Paschos (Univ. of California at San Diego, Univ. of Illinois at Urbana/Champaing), M. L. Norman (Univ. of California at San Diego), T. Abel (Center for Astrophysics at Harvard Univ.)
We use the first moment of the radiation transfer equation, applied in the cosmic intergalactic medium conditions, to solve for the energy density of the radiation field. The radiation pressure tensor, Pij, due to the primary radiation fluxes, is calculated in the optically thin regime and used for the estimate of the spatial distribution of the Eddington factors through the anzantz, fij=P_{ij}/Tr(P_{ij}). Our objective is to treat the radiation transfer problem from multiple point sources within the computational volume of a cosmological density field using a conservative discretization scheme for the moment equation. The presence of a multidute of ionizing sources in the late redshift universe can thus be simulated through the transport of the radiation flux emanating from such sources and the effect they have on the properties of the intergalactic medium can be studied. We present tests of single and multiple sources within in a constant density hydrogen medium, and a shadowing test of a point source flux from a gaussian blob. Finally, we present the preliminary results from the propagation of such field in a cosmological density distribution. The results are in agreement with the ones obtained from the single point source equation of a fixed radial Eddington factor component frr=1..
The author(s) of this abstract have provided an email address for comments about the abstract: ppaschos@cosmos.ucsd.edu