Optical depth map for 1 GeV photons in Cygnus X-3, as a function of the location of the gamma-ray source above the accretion disk of coordinates (r,φ_s,z). The level lines corresponding to τ_γγ = 10^-2, 10^-1, 1, 10, 10² are also overplotted. The accreting compact object is a 20 M_⊙ black hole (i.e. ψ = 30°, left panel) or a neutron star (ψ = 70°, right panel), located at the center of the disk (origin). The dashed line labelled “ISO” shows the contour τ_γγ = 1 in the case where the radiation from the accretion disk is fully isotropized. The maps shown here are calculated for φ_s = 0° (see Fig. 1). The inner radius of the disk is R_in = 6 r_g and the outer radius chosen at the Roche lobe radius for the compact object. Dotted lines indicate the inner and outer radius of the disk.