Chandra X-ray observations of Young Clusters I. NGC2264 Data
  We present results of a Chandra observation of a field in NGC 2264. The observations were taken with the ACIS-I camera with an exposure time of 48.1 ks. We present a catalog of 263 sources, which includes X-ray luminosity, optical and infrared photometry and X-ray variability information. We found 41 variable sources, 14 of which have a flare-like light curve, and 2 of which have a pattern of a steady increase or decrease over a 10 hour period. The optical and infrared photometry for the stars identified as X-ray sources are consistent with most of these objects being pre-main sequence stars with ages younger than 3 Myr. 
Solange V. Ramirez (SSC, Caltech), Luisa Rebull (SSC, Caltech), John   Stauffer (SSC, Caltech), Thomas Hearty (JPL), Lynne H...