Best fit temperature and photon index of the warm corona of the different objects of our sample. Different colored symbols are used for each object. They cluster in the left part of the figure, and agree with large ( >5) optical depths. For comparison, we have also reported the best fit photon indexes of the hot corona (black circles on the right). The temperature of the hot corona being fixed to 100 keV in the fits, they are all aligned vertically. The gray filled circles correspond to the best fit parameters of the hot corona from Fabian et al. (2015). The hot corona parameters cluster in the bottom right part of the figure where the optical depth is close to unity.