Journal Article

Physical characterization of southern massive star-forming regions using Parkes NH<sub>3</sub> observations

T. Hill, S. N. Longmore, C. Pinte, M. R. Cunningham, M. G. Burton and V. Minier

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 402, issue 4, pages 2682-2702
Published in print March 2010 | ISSN: 0035-8711
Published online March 2010 | e-ISSN: 1365-2966 | DOI: http://dx.doi.org/10.1111/j.1365-2966.2009.16101.x
Physical characterization of southern massive star-forming regions using Parkes NH3 observations

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We have undertaken a Parkes ammonia spectral line study, in the lowest two inversion transitions, of southern massive star formation regions, including young massive candidate protostars, with the aim of characterizing the earliest stages of massive star formation. 138 sources from the submillimetre continuum emission studies of Hill et al. were found to have robust (1,1) detections, including two sources with two velocity components, and 102 in the (2,2) transition.

We determine the ammonia line properties of the sources: linewidth, flux density, kinetic temperature, NH3 column density and opacity, and revisit our spectral energy distribution modelling procedure to derive the mass for 52 of the sources. By combining the continuum emission information with ammonia observations we substantially constrain the physical properties of the high-mass clumps. There is clear complementarity between ammonia and continuum observations for derivations of physical parameters.

The MM-only class, identified in the continuum studies of Hill et al., displays smaller sizes, mass and velocity dispersion and/or turbulence than star-forming clumps, suggesting a quiescent prestellar stage and/or the formation of less massive stars.

Keywords: line: profiles; masers; stars: early-type; stars: formation; stars: fundamental parameters; ISM: molecules

Journal Article.  13314 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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