Molecular Gas Dynamics in Massive Star Forming Regions

by Pamela Klaassen (European Southern Observatory)

Friday 13 Nov 2009, 11:00 → 12:00 Europe/Stockholm

FB52

The formation of massive stars is not nearly as well understood as their lower mass counterparts, yet they play a much greater role in Galactic evolution. Only stars more massive than 8 solar masses burn hydrogen brightly enough to form HII regions. Once an HII region forms, pressure balance suggests that accretion onto the forming star should end. How then, can stars observed to be more massive than this gain mass? With the current generation of interferometers, we do not yet have the resolution necessary to probe the dynamics deep within HII regions (for that we will need ALMA), but we can study the dynamics of the molecular gas surrounding these HII regions. Here, we present high resolution images of the molecular gas surrounding a few massive star forming regions from a combination of Submillimeter Array and James Clerk Maxwell Telescope observations. We have quantified the rotation of the warm molecular gas surrounding each HII region and the infall and outflow characteristics on larger scales. High resolution observations such as these are useful for a number of reasons: to understand the relationship between infall, rotation and outflow in high mass regions which is already understood on lower mass scales; to determine which source in a crowded field is responsible for which structures in order to see trends in gas dynamics as a function of stellar mass; and ultimately to understand the relationship between low and high mass star formation.