Star Formation in Clusters: Early Subclustering in the Serpens Core

We present high-resolution interferometric and single-dish observations of molecular gas in the Serpens cluster-forming core. Star formation does not appear to be homogeneous throughout the core, but is localized in spatially and kinematically separated subclusters. The stellar (or protostellar) density in each of the subclusters is much higher than the mean for the entire Serpens cluster. This is the first observational evidence for the hierarchical fragmentation of protocluster cores suggested by cluster formation models