The ROSAT Wide Field Camera all-sky survey of extreme-ultraviolet sources - II. The 2RE Source Catalogue

During 1990-1991 the Wide Field Camera (WFC) on the ROSAT satellite performed the first all-sky survey at EUV wavelengths. The survey was conducted in two `colours' using broad-band filters to define wavebands covering the ranges 60-140 A and 112-200 A. It was fully imaging, with effective spatial resolution of about 3 arcmin FWHM, and point source location accuracy of typically better than 1 arcmin. From an initial analysis, Pounds et al. published the WFC Bright Source Catalogue (BSC) of 383 sources. In this paper we report results from reprocessing of the complete survey database; the resulting list of sources is the `2RE' Catalogue. It contains 479 sources, of which 387 are detected in both survey wavebands, a significant advance on the BSC (80 per cent versus 60 per cent). Improvements over the original BSC include: (i) better rejection of poor aspect periods, and smaller random errors in the aspect reconstruction; (ii) improved background screening; (iii) improved methods for source detection; (iv) inclusion of a time-variability test for each source; (v) more extensive investigation of the survey sensitivity. We define the catalogue selection criteria, and present the catalogue contents in terms of tables and sky maps. We also discuss the sky coverage, source number-flux relations, optical identifications and source variability.