Some First Steps Towards a Radiation GRMHD Code: Radiative Effects on Accretion Rate onto a Kerr Black Hole

The role of radiation in general relativistic magnetohydrodynamic (GRMHD) accretion simulations is discussed through axisymmetric simulations of the evolution of an initial torus seeded with a weak magnetic field. The paper compares and contrasts the rate of accretion onto a Kerr black hole and mass flux out out of the initial torus at large radii in the GRMHD code of De Villiers and Hawley and a newly developed radiative GRMHD code. This rGRMHD code currently operates in the diffusion approximation, restricting the study of radiative effects to the bound portion of the accretion disk/jet system. However, these preliminary findings suggest that radiative effects do play a potentially significant role in regulating the accretion flow.