Kinematic structure of massive star-forming regions. I. Accretion along filaments
Abstract
Context. The mid- and far-infrared view on high-mass star formation, in
particular with the results from the Herschel space observatory, has shed
light on many aspects of massive star formation. However, these continuum studies lack
kinematic information.Aims. We study the kinematics of the molecular gas in high-mass
star-forming regions.Methods. We complemented the PACS and SPIRE far-infrared data of 16
high-mass star-forming regions from the Herschel key project EPoS with
N2H+ molecular line data from the MOPRA and Nobeyama 45 m
telescope. Using the full N2H+ hyperfine structure, we produced column density,
velocity, and linewidth maps. These were correlated with PACS 70 μm images and PACS point
sources. In addition, we searched for velocity gradients. Results. For several regions, the data suggest that the linewidth on the
scale of clumps is dominated by outflows or unresolved velocity gradients. IRDC 18454 and
G11.11 show two velocity components along several lines of sight. We find that all regions
with a diameter larger than 1 pc show either velocity gradients or fragment into
independent structures with distinct velocities. The velocity profiles of three regions
with a smooth gradient are consistent with gas flows along the filament, suggesting
accretion flows onto the densest regions.Conclusions. We show that the kinematics of several regions have a
significant and complex velocity structure. For three filaments, we suggest that gas flows
toward the more massive clumps are present.
Origin : Publication funded by an institution
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