Rosat HRI observations of the open cluster NGC 2516

We present ROSAT HRI observations of the NGC 2516, a young southern open cl uster with low metallicity. We detect 73 X-ray sources already detected wit h the PSPC and 12 new X-ray sources. The higher HRI spatial resolution allo ws us to improve the position of the previous known sources, and to better determine the optical counterparts of X-ray sources with respect to the PSP C data. We find 28 sources with no catalogued counterparts, most with faint objects within their X-ray positional error circle. Multiband CCD photometry of th ese possible counterparts shows that about half of them are consistent with being dK and dM cluster members. Assuming that they are true NGC 2516 memb ers, the derived X-ray luminosity is consistent with that observed in dK an d dM stars in more metal-rich open clusters of similar age, suggesting that the activity level at which X-ray saturation occurs is insensitive to a ch ange of a factor two in stellar metallicity.