EPoS Contribution
EPoS Contribution
Feeding a Massive Cluster along Filaments in W51

Adam Ginsburg
ESO, Munich, DE
We examine the feeding of a compact massive cluster along filaments. We present observations of dense filamentary structures feeding the central cluster within the massive proto-cluster clumps of W51. Massive (~100 Msun) cores are observed deep within the potential of the proto-clusters, indicating that huge amounts of cold gas coexist with the cluster of hypercompact HII regions. The gas density around the central cluster exceeds 106 cm-3, while the filaments linked with this structure have low densities with n~104 cm-3. New massive protostar candidates have been detected, but they do not coincide with the filaments, instead being distributed somewhat uniformly throughout the cloud. These new data hint that "clustered" and "distributed" star formation occur simultaneously within a molecular cloud and that massive star formation does not preferentially occur in filaments. Simulations of a comparable region show that ionization feedback from the massive stars should have little effect on the evolution of the molecular gas, and we see that indeed the filaments remain cold, dense, and molecular as they feed towards the young massive stars.
Caption: A radio continuum (2 cm) image of the W51 Main and IRS 2 region. The continuum is free-free emission from the HII regions; their expanding shells can be seen tracing out wispy filaments blowing away from the central sources. The green circles highlight the new candidate young massive stars; these may be young and compact HCHII regions or direct detections of stellar winds. The blue contour highlights the region with N(H2)>1023 cm-2 based on Bolocam 1.1 mm dust emission. The colored filled contours show the 2 cm absorption line of H2CO at 3 different velocities, highlighting the filaments feeding in to the HCHII clusters. The interactive figure (second link) shows the individual velocity components. The inset in the upper-left shows the W51 e1/e2 HCHII complex. The contours show regions of H2CO emission, indicating regions with mean density n>106 cm-3: these are the massive (~100 Msun) cores.
J. Bally, CU Boulder, USA
J. Darling, CU Boulder, USA
J. Koda, Caltech, USA
N. Scoville, Caltech, USA
R. Smith, ITA, Germany
C. Battersby, CfA, USA
E. Becklin, USRA, USA
R. Sankirt, USRA, USA
R. Klein, USRA, USA
A. Youngblood, CU Boulder, USA
Key publication

Suggested Sessions: Filaments