Chandra study of young stellar objects in the NGC 1333 star-forming cloud

NGC 1333, a highly active star formation region within the Perseus molecular cloud complex, has been observed with the ACIS-I detector on board the Chandra X-Ray Observatory. In our image with a sensitivity limit of similar to10(28) ergs s(-1), we detect 127 X-ray sources, most with subarcsecond positional accuracy. While 32 of these sources appear to be foreground stars and extragalactic background, 95 X-ray sources are identified with known cluster members. The X-ray luminosity function of the discovered young stellar object (YSO) population spans a range of log L-X similar or equal to 28.0-31.5 ergs s(-1) in the 0.5-8 keV band, and absorption ranges from log N-H similar or equal to 20 to 23 cm(-2). Most of the sources have plasma energies between 0.6 and 3 keV, but a few sources show higher energies up to similar to7 keV. Comparison with K-band source counts indicates that we detect all of the known cluster members with K < 12 and about half of the members with K > 12. K similar or equal to 11, the peak of the K-band luminosity function, corresponds to 0.2-0.4 M. stars for a cluster age of similar to1 Myr. We detect seven of the 20 known YSOs in NGC 1333 producing jets or molecular outflows as well as one deeply embedded object without outflows. No evident difference in X-ray emission of young stars with and without outflows is found. Based on the complete subsample of T Tauri stars, we also find no difference in X-ray properties and X-ray production mechanism of stars with and without K-band excess disks. Several other results are obtained. We suggest that the X-ray emission from two late B stars that illuminate the reflection nebula originates from unresolved late-type companions. Two T Tauri stars are discovered in the ACIS images as previously unknown components of visual binaries. A good correlation L-X proportional to J is seen, which confirms the well-known relation L-X proportional to L-bol found in many star-forming regions. Based on spectral analysis for the X-ray counterpart of SVS 16, we establish that the column density NH is much lower than that expected from near-IR photometry so that its X-ray luminosity, log L-X similar or equal to 30.6 ergs s(-1), is not unusually high.