EPIC spectra of 9 Sgr as a function of orbital phase along with the best-fit thermal non-equilibrium (Eq. (4)) models. The top panels illustrate the EPIC-pn (blue), EPIC-MOS1 (black), and EPIC-MOS2 (green) data. The bottom panels yield the contributions of the different energy bins to the χ² of the fit, with the sign of δχ² being defined as the sign of the observation minus the model. All panels have the same vertical and horizontal scales. We note the relatively constant flux level in the soft part of the spectrum, but also the strong changes in the level of the hard flux between φ = 0.627 and the spectra taken close to periastron.