X-ray and IR point source identification and characteristics in the embedded, massive star-forming region RCW 108

We report on the results of an approximately 90 ks Chandra observation of a complex region that hosts multiple sites of recent and active star formation in ARA OB1a. The field is centered on the embedded cluster RCW 108 - IR and includes a large portion of the open cluster NGC 6193. We detect over 420 X-ray sources in the field and combined these data with deep near-IR, Spitzer/IRAC and Midcourse Space Experiment ( MSX) mid-IR data. We find about 360 of the X-ray sources have near-IR counterparts. We divide the region into five parts based on the X-ray point source characteristics and extended 8 mu m emission. The most clearly defined regions are the central region, identified by embedded sources with high luminosities in the both the near-IR and X-ray as well as high X-ray temperatures (similar to 3 keV), and the eastern region, identified by low extinction and similar to 1 keV X-ray temperatures. Other regions, identified by their directional relationship to RCW 108 - IR, are less uniform representing combinations of the first two regions, independent star formation epochs, or both. The cluster members range in X-ray luminosity from 10(29) to 10(33) erg s(-1). Over 18% of the cluster members with over 100 counts exhibit flares. All sources with over 350 counts are variable. Overall about 10% ( 16% in RCW 108 - IR) appear to have optically thick disks as derived from their position in the ( J - H), ( H - K) diagram. The disk fraction becomes much higher when IRAC data are employed. The largest fraction of X-ray sources is best described as possessing some disk material via a more detailed extinction fitting. We fit the bulk of the X-ray spectra as absorbed Raymond-Smith- type plasmas, and find that the column to the RCW 108-IR members varies from 10(21) to 10(23) cm(-2). We find that the field contains 41 candidate O or B stars, and estimate that the total number of pre-main-sequence stars in the field is about 1600 +/- 200. Approximately 800 are confined to the 3 ' (similar to 1.1 pc) central region.