Hardness-ratio diagrams of sources with error-bars smaller than 0.3. Black squares are sources classified as XRBs (Sect. 5.4), orange diamonds are SNRs (Sect. 5.5), violet plus signs are SSSs (Sect. 5.6), green crosses are ULXs (Sect. 5.8), cyan stars are foreground stars (Sect. 5.1), red triangles are background sources (Sect. 5.2), and blue circles are sources not classified. The lines are the hardness ratios calculated for different spectral models and column densities, as described in Sect. 4.3.