The distribution of the XGPS/2XMM sources in the EPIC pn hardness ratio diagrams. For clarity, we show only those sources with hardness ratio errors less than 0.3. Upper panel: Larger red squares; sources having an optical or infrared counterpart with matching probability above 90%. Small black squares; the remaining XGPS sources. The overplotted characters (in blue) show the sources observed at the telescope. Stars - identified active coronae; V  −  cataclysmic variables; X  −  high-mass and low-mass X-ray binary candidates; W – Wolf-Rayet; U  −  sources unidentified at the telescope. The green strips illustrate the locus occupied by extragalactic sources, computed assuming a power-law spectrum of photon index 1.7 and the total Galactic absorption on the line of sight. Lower panel: corresponding id numbers of the XGPS sources observed at the telescope.