SERENDIPITOUS EUV SOURCES DETECTED DURING THE FIRST YEAR OF THE EXTREME-ULTRAVIOLET-EXPLORER RIGHT-ANGLE PROGRAM

We report the detection of 114 extreme ultraviolet (EUV; 58-740 Angstr om) sources, of which 99 are new serendipitous sources, based on obser vations made with the imaging telescopes on board the Extreme Ultravio let Explorer (EUVE) during the Right Angle Program (RAP). These data w ere obtained using the survey scanners and the Deep Survey instrument during the first year of the spectroscopic guest observer phase of the mission, from January 1993 to January 1994. The data set consists of 162 discrete pointings whose exposure times are typically two orders o f magnitude longer than the average exposure times during the EUVE all -sky survey. Based on these results, we can expect that EWE will seren dipitously detect approximately 100 new EUV sources per year, or about one new EUV source per 10 sq deg, during the guest observer phase of the EWE mission. New EUV sources of note include one B star and three extragalactic objects. The B star (HR 2875, EUVE J0729-38.7) is detect ed in both the Lexan/B (similar to 100 Angstrom) and Al/Ti/C (similar to 200 Angstrom) bandpasses, and the detection is shown not to be a re sult of UV leaks. We suggest that we are detecting EW and/or soft x ra ys from a companion to the B star. Three sources, EUVE J2132+10.1, EUV E J2343-14.9, and EUVE J2359-30.6 are identified as the active galacti c nuclei MKN 1513, MS2340.9-1511, and 1H2354-315, respectively.