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The RMS survey: Ammonia mapping of the environment of massive young stellar objects

Urquhart, J.S., Figura, C.C., Moore, T.J.T., Csengeri, T., Lumsden, S.L., Pillai, T., Thompson, M.A., Eden, D.J., Morgan, L.K. (2015) The RMS survey: Ammonia mapping of the environment of massive young stellar objects. Monthly Notices of the Royal Astronomical Society, 452 (4). pp. 4029-4053. ISSN 0035-8711. (doi:10.1093/mnras/stv1514) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided) (KAR id:52182)

The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided. (Contact us about this Publication)
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http://www.dx.doi.org/10.1093/mnras/stv1514

Abstract

We present the results of ammonia observations towards 66 massive star forming regions identified by the Red Midcourse Space Experiment Source survey. We have used the Green Bank Telescope and the K-Band Focal Plane Array to map the ammonia (NH<inf>3</inf>) (1,1) and (2,2) inversion emission at a resolution of 30 arcsec in 8 arcmin regions towards the positions of embedded massive star formation. We have identified a total of 115 distinct clumps, approximately two-thirds of which are associated with an embedded massive young stellar object or compact HII region, while the others are classified as quiescent. There is a strong spatial correlation between the peak NH<inf>3</inf> emission and the presence of embedded objects. We derive the spatial distribution of the kinetic gas temperatures, line widths, and NH<inf>3</inf> column densities from these maps, and by combining these data with dust emission maps we estimate clumpmasses, H<inf>2</inf> column densities and ammonia abundances. The clumps have typical masses of ~1000 M· and radii ~0.5 pc, line widths of ~2 kms-1 and kinetic temperatures of ~16-20 K. We find no significant difference between the sizes and masses of the star-forming and quiescent subsamples; however, the distribution maps reveal the presence of temperature and line width gradients peaking towards the centre for the star-forming clumps while the quiescent clumps show relatively uniform temperatures and line widths throughout. Virial analysis suggests that the vast majority of clumps are gravitationally bound and are likely to be in a state of global free fall in the absence of strong magnetic fields. The similarities between the properties of the two subsamples suggest that the quiescent clumps are also likely to form massive stars in the future, and therefore provide an excellent opportunity to study the initial conditions of massive pre-stellar and protostellar clumps. © 2015 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

Item Type: Article
DOI/Identification number: 10.1093/mnras/stv1514
Uncontrolled keywords: ISM: molecules, Radio lines: ISM, Stars: early-type, Stars: formation
Subjects: Q Science > QB Astronomy > QB460 Astrophysics
Divisions: Faculties > Sciences > School of Physical Sciences > Centre for Astrophysics and Planetary Sciences
Depositing User: James Urquhart
Date Deposited: 23 Nov 2015 17:11 UTC
Last Modified: 29 May 2019 16:27 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/52182 (The current URI for this page, for reference purposes)
Urquhart, J.S.: https://orcid.org/0000-0002-1605-8050
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