The Second Extreme-Ultraviolet Explorer Source Catalog

We present the second catalog of extreme-ultraviolet objects detected by the Extreme-Ultraviolet Explorer. The data include (1) all-sky survey detections from the initial 6 month scanner-survey phase, (2) additional scanner detections made subsequently during specially programmed observations designed to fill in low-exposure sky areas of the initial survey, (3) sources detected with deep-survey-telescope observations along the ecliptic, (4) objects detected by the scanner telescopes during targeted spectroscopy observations, and ( 3) other observations. We adopt an innovative source detection method that separates the usual likelihood function into two parts: an intensity diagnostic and a profile diagnostic. These diagnostics allow each candidate detection to be tested separately for both signal-to-noise ratio and conformance with the known instrumental point-spread function. We discuss the dependence of the false-alarm rate and the survey's completeness on the survey's sensitivity threshold. We provide three lists of the EUV sources detected: the all-sky survey detections, the deep-survey detections, and sources detected during other phases of the mission. Each list gives positions and intensities in each wave band. The total number of objects listed is 734. For approximately 65% of these we also provide plausible optical, UV, radio, and/or X-ray identifications.