We report the discovery of multiple low-luminosity X-ray sources near the center of the nearby post-core-collapse globular cluster NGC 6397. In an 18 ks exposure of the cluster with the ROSAT High Resolution Imager (HRI), seven distinct sources with significance greater than 4 σ are detected in the 36' diameter field of view. At least three of these sources are very likely cluster members given their positions less than 1' from the cluster center. The source closest to the center is clearly extended and may be due to a group of three or more point sources which are incompletely resolved from one another. If this is the case, the cluster contains at least five point sources with luminosities in the range of L_x_~ 2-10 x 10^31^ ergs s^-1^ in the ROSAT band (0.1-2.4 keV). Additional fainter sources or low-level diffuse emission may also be required to fully account for the observed flux. These are the faintest X-ray sources known in globulars. Their luminosities, numbers, and spatial distribution are consistent with their being cataclysmic variables and support the hypothesis that the low-luminosity X-ray sources discovered with the Einstein Observatory (Hertz & Grindlay 1983) represent high-luminosity members of a larger population of CVs in clusters.
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Cool et al. (1993) studied this question.