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| EPoS Contribution |
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Probing the Chemical and
Kinematical Structure of High-mass Star-forming Cores
Megan Reiter Steward Observatory, University of Arizona, Tucson, AZ, USA | |
| We have observed 11 molecular transitions of HCO+, N2H+, HNC, SO, CCH, and CH3OH towards a sample of 27 high-mass clumps selected towards water masers to systematically study the chemical and kinematical structure of high-mass clumps. We present maps of the integrated intensity, compare the spatial distributions of molecular emission with dust continuum observations, and compare size, mass, and column density derived from each tracer. We find N2H+ emission is spatially differentiated towards a few very luminous cores and the N2H+ integrated intensity does not correlate well with dust continuum flux, while molecular tracers with larger effective densities (n_eff > 105 cm-3) appear to correlate more strongly with the dust continuum intensity and each other. We calculate L' for the clumps and test the recent radiative transfer predictions of Narayanan et al. for galactic molecular emission. We also observe an excess of blue asymmetric line profiles for HCO+ J=3-->2, every core with a HCO+ blue asymmetry also displays a blue asymmetry in HCN J=3-->2 indicating that this may be the signature of large scale infall in high-mass clumps. | |
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| Caption: Contour map of the dust continuum and the integrated intensity of the transitions listed at the top of each frame. The lowest contour and contour intervals are listed at the bottom of each panel. Notice that N2H+ is the only dense gas tracer that is not centrally peaked, though both transitions trace this differentiation, suggesting that it is a physical separation of the N2H+ gas and not a radiative transfer effect. While HNC and HCO+ both show extended emission towards the southwestern peak, the emission in both molecules is much more centrally peaked than for either transition of N2H+, which is strongest several arcseconds from the central position. | |
| Collaborators: Y.L. Shirley, U of Arizona, USA J. Wu, CfA, USA A. Wootten, NRAO, USA C. Brogan, NRAO, USA K. Tatematsu, NAOJ, Japan | Suggested Session:
Cores and Collapse, Massive Stars |