James Di Francesco
Herschel Observations of the Massive Star-Forming Region NGC 7538
M. A. Reid (University of Toronto), P. G. Martin (University of Toronto), D. Ward-Thompson (Cardiff University), J. Kirk (Cardiff University), F. Motte (CEA) and the HOBYS team
We present the first results of Herschel observations of the massive star-forming region, NGC 7538, taken as part of the Herschel imaging study of OB Young Stellar Objects (HOBYS) key programme. These PACS and SPIRE maps cover an area of approximately one square degree at five different wavebands. For the first time, they allow us not only to identify and characterize hundreds of compact sources involved in star formation in this region, but also to investigate their relationships with their environments. These data reveal for the first time that the region consists of many interconnected filaments with clusters of warm sources at some of the intersections of the filaments. Although most of the smaller filaments appear to be distributed randomly, consistent with turbulent origins, some appear to be the walls of evacuated cavities. We report the discovery of what appears to be a large ring of triggered star formation which is nearly 11 pc wide along its long axis. In addition, we demonstrate the existence of a significant population of massive, cold compact sources which may prove to be analogues of low-mass "Class 0" objects.