X-Ray and Infrared Point Source Identification and Characteristics in the Embedded, Massive Star-Forming Region RCW 38

We report on results of a 96.7 ks Chandra observation of one of the youngest,most embedded and massive young stellar clusters studied in X-rays - RCW 38. Wedetect 460 sources in the field of which 360 are confirmed to be associatedwith the RCW~38 cluster. The cluster members range in luminosity from ~10^30ergs s^-1 to 10^33.5 ergs s^-1. Over ten percent of the cluster members withover 100 counts exhibit flares while about 15% of cluster members with over 30counts are variable. Of the sources identified as cluster members, 160 havenear-infrared (NIR) counterparts either in the 2MASS database or detected viaVLT observations. Of these about 20% appear to have optically thick disks. Anadditional 353 members are identified through NIR observations of which atleast 50% possess optically thick disks. We fit over 100 X-ray sources asabsorbed Raymond-Smith type plasmas and find the column to the cluster membersvaries from 10^21.5 to 10^23 per sq cm. We compare the gas to dust absorptionsignatures in these stars and find Nh= A_v x 2 x 10^21 cm^-2. We find that thecluster contains 31 candidate OB stars and is centered about 10" (0.1 pc) westof the primary source of the ionization, the O5 star IRS 2. The cluster has apeak central density of about 400 X-ray sources pc^-2. We estimate that thetotal cluster membership exceeds 2000 stars.Comment: Accepted by AJ- 114 pages including 21 figures and 13 full length tables. 6 Figures converted to jpg