The ROSAT North Ecliptic Pole Deep Survey

Abstract
This paper presents the results of a survey of faint ROSAT sources in the region of the North Ecliptic Pole. Identifications have been made for 18 point-like sources brighter than 1.0 × 10−14 erg s−1 cm−2 in the 0.5-2.0 keV energy band. The identification of a further two sources remains uncertain. The completeness of this survey is thus 90 per cent. We discuss the astrophysical objects identified, and consider their possible implications. Finally, we consider the difficulties in identifying the remaining sources and describe the ultimate limitations to the depth of ROSAT X-ray surveys.