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Ionized and Molecular Gas Dynamics in High-Mass Star Forming Regions

Submitter: Pamela Klaassen
Description: Despite great strides in the field, it is still not clear how high-mass protostars continue to accrete material once it has begun ionizing its surroundings (forming an HII region). With sensitive new instruments, we can characterize the dynamics of both the molecular and ionized gas in these regions. This gives a much greater understanding of the physics underlying the bulk motions in these systems. By studying infall, outflow and rotation on thousands of AU scales, we can quantify the byproducts of accretion. Does accretion continue beyond the formation of an HII region? Early results suggest yes. In some regions (e.g. W51e2) the ionized and molecular gas appear to be co-rotating. In others, (e.g. G10.6), the ionized and molecular infall signatures are consistent. We present these results in the context of continued accretion onto an HII region. In K3-50A, there are previous observations of an ionized outflow, but no molecular one. Here, we present a study of both the ionized and molecular gas dynamics in K3-50A using H41a and HCO+ (J=1-0) observations from CARMA. We find evidence that the ionized outflow in this region is indeed entraining some of the molecular gas as it escapes the HII region, but that the bulk of the molecular gas (as traced by HCO+) is continuing to infall onto the HII region perpendicular to this outflow.
Copyright: Bill Saxton, NRAO/AUI/NSF
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