Observations of high-latitude X-ray sources with the Uhuru satellite.

Uhuru observations of 22 unidentified high-galactic-latitude X-ray sources over the period from December 1970 to April 1973 are analyzed. The results confirm the existence of at least 19 sources, improve the positions for several of them, and yield evidence that some are variable. Two sources, 3U 0042+32 and 3U 1809-50, are found to be variable at the 3-sigma level. The improved positions for 3U 1555+27 and 3U 0405+10 confirm that these sources are, respectively, the Abell galaxies A2142 and A478.