CARTOON: General relativistic radiative transfer code based on phOton number conservation in curved space-time

3D Photon Conserving Code for Time-dependent General Relativistic Radiative Transfer : CARTOON

We develop the 3-dimensional general relativistic radiative transfer code:cartoon (calculation code of authentic radiative transfer based on photonnumber conservation in curved space-time) which is improved from the 2-dimensional code: artist developed by takahashi & umemura (2017).In cartoon, the frequency-integrated general relativistic radiative transfer equation is solved in a photon number-conserving manner, and the isotropic and coherent scattering in the zero angular momentum observers (zamo) frame and the fluid rest frame is incorporated.The position of the wavefront coincides with the analytical solution and the number of photons remains constant until the wavefront reaches the event horizon.Energy conservation of the radiation is also guaranteed by calculating the average energy of photons.The time variation of the intensity map on the observer s screen can be simultaneously and consistently calculated with the time variation of the radiation field around the black hole.