Temperature dependence on the optical depth for various spin values given in the boxes. The gray gradient of lines represents the matter structure calculated at different radii, with the darkest line at r_in, and the lightest line at r_out. The colored lines show the simulation with maximum temperature, which is consistent with the dashed line in Fig. 2. The corresponding radial point where the temperature drop is observed is labeled and marked in green text. The parameters other than spin are chosen to be canonical values from Table 2. As this is the temperature structure, it is independent of the viewing angle.