Clustering/Populations -- Oral Presentation

A Spitzer Survey of Young Stellar Clusters

Robert Gutermuth, University of Rochester

S.T. Megeath (CfA), J.L. Pipher (UR), L.E. Allen (CfA), P.C. Myers (CfA), G.G Fazio (CfA)

To build a comprehensive picture of star-formation in clusters, we have designed and executed the Spitzer Young Stellar Cluster Survey. We have selected over thirty young (< 3 Myr) stellar clusters and groups within 1 kpc of the Sun that are still associated with their natal molecular clouds for observations with the IRAC and MIPS instruments onboard Spitzer. Almost all of the clusters have now been observed. In addition, we have obtained ground based near-IR, submillimeter and millimeter-wave imaging for the sample. I will present a study of the populations of young stellar objects detected in several of these regions, using combined near-IR and Spitzer colors to identify young stars with disks and protostellar envelopes. The particular emphasis will be on identifying structure in the stellar distributions and relating it to natal gas and dust distributions. These data show that embedded, forming stellar clusters are often not spherically symmetric structures, but can be elongated and clumpy, surrounded by lower density halos of young stars. The morphologies of the clusters may reflect the initial structure of the dense natal molecular gas, and once this gas is dispersed, our data show that stellar dynamical evolution can quickly erase this structure. Finally, we will use these data to explore the impact of high stellar densities and massive star proximity to disk evolution in these clusters.