Precise positions and optical search for the 38 second X-ray, pulsar near OAO 1653-40 and upper limit on X-ray emission from, V861 Sco.

The region of the binary system V861 Scorpii, whose secondary has been suggested as a black hole candidate, was observed with the HEAO 1 X-ray observatory during an 8-hour pointed observation on September 4, 1978. An upper limit of 1.0 micro Jy (within three standard deviations) is placed on X-ray emission from V861 Sco during this observation. This effectively removes the secondary from the list of black hole candidates. The presence of a 38 sec pulsar in the region is confirmed, precise (0.63 sq arcmin) positions are given, and a search for the optical counterpart is described.