Top-left panel: g′ magnitude distribution of XMM sources observed in this work (dashed histogram), sources with certain identifications (solid histogram) and unidentified sources (hatched histogram). Bottom-left panel: redshift distribution of BLAGN (cross hatched region), emission-line objects (hatched region) and ALGs (shaded region). Top-right panel: plot of the X-ray flux at 0.5–2 keV (erg cm−2 s−1) band against the optical g′ magnitude for BLAGN (filled circles), ELGs (crosses), ALGs (filled triangles), stars (open squares) and unidentified sources (open circles). Bottom-right panel: X-ray flux distribution in 0.5–2 keV (erg cm−2 s−1) band for our initial sample (dashed histogram), the spectroscopically identified sources (solid histogram) and the unidentified sources (hatched region).
