Discovery of two periodic X-ray pulsators.

Results are reported for X-ray and optical observations of the region of the sky containing the X-ray source 3U 1258-61. Ariel 5 observations over the energy range from 2 to 20 keV are analyzed, and pulsations with two independent periods are detected along with the sources 3U 1258-61, 3U 1320-61, and A1239-59. Both A1239-59 and 3U 1258-61 are found to have relatively hard spectra with spectral indices of less than 2 and corresponding kT values in excess of 10 keV. UBVRI photographic plates of the error box of 3U 1258-61 are examined in a search for that source's optical counterpart, and four stars having corrected (B-V) colors of less than 1.0 are listed along with their V magnitudes, (B-V) colors, and (U-B) colors. It is concluded that there are no promising candidates for optical identification with 3U 1258-61.