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The North-Ecliptic Pole is an important region for extragalactic surveys.Deep/wide contiguous surveys are being performed by several spaceobservatories. We analyse all ROSAT pointed and survey observations within 40deg2 around the NEP, restricting the field-of-view to the inner 30' radius. Weobtain an X-ray catalogue of 805 sources with 0.5-2 keV fluxes >2.9E-15 cgs, afactor of three deeper than the ROSAT All-Sky Survey in this field. Thesensitivity and angular resolution of our data are comparable to the eROSITAAll-Sky Survey expectations. We use HEROES optical and near-infrared imagingphotometry from Subaru and CFHT telescopes together with literature cataloguesand a new deep and wide Spitzer survey in the field to identify X-ray sourcesand calculate photometric redshifts for the candidate counterparts. Inparticular we utilize mid-IR colours to identify AGN X-ray counterparts.Despite relatively large error circles and faint counterparts, confusion andsystematic errors, we obtain a rather reliable catalogue of 766 opticalcounterparts, redshifts and optical classifications. We find a new populationof luminous absorbed X-ray AGN at large redshifts, not recognized in previousX-ray surveys, but identified in our work due to the unique combination ofsurvey solid angle, X-ray sensitivity and multiwavelength photometry. We alsouse the WISE and Spitzer photometry to identify a sample of 185 AGN selectedpurely through mid-IR colours, most of which are not detected by ROSAT. Theirredshifts and upper limits to X-ray luminosity and X-ray to optical flux ratiosare even higher than for the new class of X-ray selected luminous AGN2. Thisunique dataset is important as reference for future deep surveys in the NEPregion. Most of the absorbed distant AGN should be readily picked up byeROSITA, but they require sensitive mid-IR imaging to be recognized as opticalcounterparts.

The ROSAT Raster Survey in the North-Ecliptic Pole Field: X-ray Catalogue and Optical Identifications