fitting the spectral model to the data (using $\rm{\chi^2}$ statistics). Free parameters of the fit were the normalisation of the spectral components, the temperatures, and the relative abundances of the `apec` models. The fit was done using a fixed foreground column density ($\rm{n_H~[cm^{-2}]}$), which was determined from the Leiden/Argentine/Bonn (LAB) survey of Galactic HI . Where we found the absorption to vary significantly across the FOV of an observation $\rm{n_H}$ was set as additional free parameter of the fit . Additional absorption of about 5 per cent can be caused by molecular hydrogen in the foreground [$\rm{H_2}$ X-ray absorption, see @2013MNRAS.431..394W]. We did not include the additional absorption by $\rm{H_2}$ because the influence on the spectral form in the 3keV range is negligible. If the two temperatures were separated by less than 30 per cent or if the normalisation of one component was less than one per cent of the second we discarded the second component and fit only a one-temperature `apec` model (see Tab. \[tab:xspecpars\]).

Once the best fit was identified, we calculated the confidence intervals (99.7 per cent) for the additional flux added by the Gaussian using a Monte Carlo Markov Chain (MCMC) method with length of 10000 