Chandra Spitzer and VLA observations of Young Stellar Clusters.
Scott Wolk (Smithsonian Astrophysical Observatory) , R. Osten (UMD), T. Bourke (CfA), S.T. Megeath (U. Toledo), B.D. Spitzbart (CfA), E. Winston (U. Dublin)
We examine the properties of embedded clusters within 2 kpc using new data from the Chandra X-ray Observatory and the Spitzer Space Telescope, as well as data from the VLA for the closest systems. We use surveys of entire molecular clouds to understand the range and distribution of cluster membership, size, and surface density. The data demonstrate clearly that there is a continuum of star-forming environments, from relative isolation to dense clusters. Using the combined Spitzer and CXO data allows a very accurate assessment of cluster size. We have detected differences in the spatial distributions of Class II and Class III objects (a.k.a. classical and naked T Tauri stars). Comparison of the class fraction as a function of cluster age is crucial to understanding disk evolution. The simultaneous radio and X-ray data reveal a disconnect between the two magnetic activity signatures in comparison with nearby active stars and the Sun. This evidence comes from both the lack of correlations of time-averaged luminosities as well as simultaneous measures of radio and X-ray variability which show the absence of the Neupert effect. Further the radio flux is anti-correlated with spectral index in variable sources. Taken together this indicates that the variability in these very young stars is non-solar in nature. We have also detected a radio flare from a Class II object and a score of transition objects in X-rays. These latter data allow us to start the process of understanding the high energy environment in this crucial planet building stage.