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ATLASGAL - Molecular fingerprints of a sample of massive star-forming clumps

Urquhart, JS, Figura, C, Wyrowski, F, Giannetti, A, Kim, WJ, Wienen, M, Leurini, S, Pillai, T, Csengeri, T, Gibson, SJ, Menten, KM, Moore, TJT and Thompson, MA (2019) ATLASGAL - Molecular fingerprints of a sample of massive star-forming clumps. Monthly Notices of the Royal Astronomical Society, 484 (4). pp. 4444-4470. ISSN 0035-8711

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Abstract

We have conducted a 3-mm molecular-line survey towards 570 high-mass star-forming clumps, using the Mopra telescope. The sample is selected from the 10 000 clumps identified by the ATLASGAL (APEX Telescope Large Area Survey of the Galaxy) survey and includes all of the most important embedded evolutionary stages associated with massive star formation, classified into five distinct categories (quiescent, protostellar, young stellar objects, H ii regions, and photon-dominated regions). The observations were performed in broad-band mode with frequency coverage of 85.2-93.4 GHz and a velocity resolution of 1/40.9 km s '1, detecting emission from 26 different transitions. We find significant evolutionary trends in the detection rates, integrated line intensities, and abundances of many of the transitions and also identify a couple of molecules that appear to be invariant to changes in the dust temperature and evolutionary stage [N 2 H + (1-0) and HN 13 C (1-0)]. We use the K-ladders for CH 3 C 2 H (5-4) and CH 3 CH (5-4) to calculate the rotation temperatures and find around one-third of the quiescent clumps have rotation temperatures that suggest the presence of an internal heating source. These sources may constitute a population of very young protostellar objects that are still dark at 70 mum and suggest that the fraction of truly quiescent clumps may only be a few per cent. We also identify a number of line ratios that show a strong correlation with the evolutionary stage of the embedded objects and discuss their utility as diagnostic probes of evolution.

Item Type: Article
Additional Information: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2019 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Uncontrolled Keywords: 0201 Astronomical and Space Sciences
Subjects: Q Science > QB Astronomy
Divisions: Astrophysics Research Institute
Publisher: Oxford University Press
Date Deposited: 18 Mar 2019 09:58
Last Modified: 18 Mar 2019 11:00
DOI or Identification number: 10.1093/mnras/stz154
URI: http://researchonline.ljmu.ac.uk/id/eprint/10357

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