ChandraX‐Ray Observations of the Young Open Cluster NGC 2516

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Abstract
We present a comprehensive study of the Chandra X-ray observations of the young open cluster NGC 2516. We have analyzed eight individual Chandra observations. We have combined the data to achieve the greatest sensitivity, reaching down to log fX = -14.56 (ergs s-1 cm -2), or log LX = 28.69 (ergs s-1) at the distance of NGC 2516. Out of 284 X-ray sources detected, 155 are identified with photometric cluster members, with very little ambiguity. We have studied the X-ray luminosity functions for the various spectral types, correcting for nonmember contamination those for later type stars. We find strong X-ray emission from a couple of B stars that cannot be due to companions. Among A stars, chemically peculiar stars show a detection fraction much larger than normal A stars. The luminosity functions decrease monotonically from F to M stars, and those for K stars are significantly lower than similar stars in the Pleiades, a cluster only slightly younger than NGC 2516. We discuss possible causes of this discrepancy, including differences in age and stellar rotation.