X-ray observations of globular clusters with ANS.

Pointed observations were resumed with the ANS satellite during March-April 1976 to search for both steady and burst X-ray emission from globular clusters. No new sources were found among the 16 clusters observed; significant upper limits and required variability ranges are reported. Bursts were detected from MXB 1730-335, and steady emission (but no bursts) was detected from both NGC 6624 and the source A1850-08 near the diffuse globular cluster NGC 6712. The improved ANS position for this latter source is 4 plus or minus 3 arcmin (90% confidence level) south of the cluster, and the combined ANS-Uhuru-Ariel 5 error box (about 12 x 4 arcmin) is centered SE of the cluster and includes several variable stars outside the cluster. However, since the core cannot be excluded, NGC 6712 could resemble the centrally condensed cluster sources (possibly containing massive central objects) if the cluster is being disrupted.