A VLA survey of unidentified HEAO-1 X-ray sources.

The authors have employed a new technique to uncover candidates for unidentified bright X-ray sources where traditional methods have proved unsuccessful. The C configuration VLA was used at 20 cm to search for 47 unidentified sources detected in the HEAO-1 all-sky X-ray survey. Approximate pointing positions were obtained by superimposing the large error boxes from the NRL experiment and the grid of small diamonds from the Scanning Modulation Collimator. Radio maps of the 30arcmin primary beam were made and 238 radio sources (with flux densities as small as 1 - 3 mJy) were detected in or near the diamond-shaped error boxes. A search was made for the associated optical objects on POSS prints, and tentative classifications of the resulting radio/optical candidates were made. The candidate X-ray identifications include five possible RS CVn systems, three active galactic nuclei, three galaxy or cluster sources, and two X-ray binaries.