|
Description
The authors of this study have explored the young stellar populations in the Rosette Molecular Cloud (RMC) region with high spatial resolution X-ray images from the Chandra X-ray Observatory, which are effective in locating weak-lined T Tauri stars as well as disk-bearing young stars. A total of 395 X-ray point sources are detected, 299 of which (76%) have an optical or near-infrared (NIR) counterpart identified from deep FLAMINGOS images. From X-ray and mass sensitivity limits, the authors infer a total population of ~1700 young stars in the survey region. Based on smoothed stellar surface density maps, they investigate the spatial distribution of the X-ray sources and define three distinctive structures and substructures within them. Structures B and C are associated with previously known embedded IR clusters, while structure A is a new X-ray-identified unobscured cluster. A high-mass protostar RMCX 89 = IRAS 06306+0437 and its associated sparse cluster are studied. The different subregions are not coeval but do not show a simple spatial-age pattern. Disk fractions vary between subregions and are generally <~ 20% of the total stellar population inferred from the X-ray survey. The data are consistent with speculations that triggered star formation around the H II region is present in the RMC, but do not support a simple sequential triggering process through the cloud interior. While a significant fraction of young stars are located in a distributed population throughout the RMC region, it is not clear if they originated in clustered environments. This HEASARC table contains the 348 primary sources listed in Table 1 of the reference paper, as well as the 47 tentative sources listed in Table 2 (the latter having a likelihood > 10<sup>-3</sup> of being a spurious background fluctuation based on Poisson statistics), to make a total of 395 X-ray sources. The information on optical and infrared counterparts to these X-ray sources which was provided in Table 4 of the reference paper has also been included herein. In order to allow users to clearly identify these 2 samples, the HEASARC has created a parameter source_sample which is set to 'P' for the Table 1 primary sources and to 'T' for the Table 2 tentative sources. This HEASARC table also contains the X-ray spectroscopic information derived for 158 sources which have photometric significance (the snr parameter) >= 2.0 which was presented in Table 3 of the reference paper. All spectral fits used the "wabs(apec)" model in XSPEC and assumed 0.3 * Z_Sun abundances. The quoted emission measures and X-ray luminosities assume a distance to the Rosette molecular cloud of 1.4 kpc. This table was created by the HEASARC in July 2009 based on the merger of electronic versions of tables 1, 2, 3 and 4 from the above reference which were obtained from the ApJ web site. This is a service provided by NASA HEASARC .
|
