Radiative transfer in moving spherical atmospheres II. Analytical solution for fully relativistic radial motions

Based on the well known solution of the timeindependent radiative transfer equation along a ray and on suitable point transformations, general quadrature solutions of the monochromatic transfer equation for plane-parallel, spherically-symmetric and arbitrarily shaped 3D configurations with differential motion are derived for the observer’s and the comoving frame. The source function is assumed to be given; however, the scattering case requires only a simple iteration in addition. Since complete Lorentz transformations are used, the velocities are not restricted. It is shown that in many cases the explicit form of the transfer equation –which often is quite complicated – is not required for the determination of the specific intensities.