VizieR Online Data Catalog: Optical counterparts of ROSAT X-ray in 2 fields (Greiner+, 2015)

The optical identification of large number of X-ray sources such as those from the ROSAT All-Sky Survey is challenging with conventional spectroscopic follow-up observations.

We investigate two ROSAT All-Sky Survey fields of size 10°x10° each, one at galactic latitude b=83° (26 Com), the other at b=-5° (gamma Sge), in order to optically identify the majority of sources.

We used optical variability, among other more standard methods, as a means of identifying a large number of ROSAT All- Sky Survey sources. All objects fainter than about 12mag and brighter than about 17mag, in or near the error circle of the ROSAT positions, were tested for optical variability on hundreds of archival plates of the Sonneberg field patrol.

(4 data files).