Absorption corrected X-ray (0.5−7 keV) luminosity as a function of redshift for the 31 X-ray sources in the MIDIS survey coloured by column density (N_H). Where appropriate the X-ray luminosity has been updated to reflect the spectroscopic redshift, see Section 4.2. In the background we show the X-ray emitting sources identified by Luo et al. (2017) in the 7 Ms survey. We show the distribution for the MIDIS sources (black histogram) and 7 Ms sources (grey histogram, scaled down by a factor 10) on each axis. A clear trend of increasing X-ray luminosity with redshift is apparent, as is expected for a flux-limited sample.