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The Molecular Gas Environment in the 20 KMS−1 Cloud in the Central Molecular Zone

Lu, X and Zhang, Q and Kauffmann, J and Pillai, T and Longmore, SN and Kruijssen, JMD and Battersby, C and Liu, HB and Ginsburg, A and Mills, EAC and Zhang, Z-Y and Gu, Q (2017) The Molecular Gas Environment in the 20 KMS−1 Cloud in the Central Molecular Zone. The Astrophysical Journal, 839 (1). ISSN 1538-4357

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Abstract

We recently reported a population of protostellar candidates in the 20 kms−1 cloud in the Central Molecular Zone of the Milky Way, traced by H2O masers in gravitationally bound dense cores. In this paper, we report high-angular-resolution (_3′′) molecular line studies of the environment of star formation in this cloud. Maps of various molecular line transitions as well as the continuum at 1.3 mm are obtained using the Submillimeter Array. Five NH3 inversion lines and the 1.3 cm continuum are observed with the Karl G. Jansky Very Large Array. The interferometric observations are complemented with single-dish data. We find that the CH3OH, SO, and HNCO lines, which are usually shock tracers, are better correlated spatially with the compact dust emission from dense cores among the detected lines. These lines also show enhancement in intensities with respect to SiO intensities toward the compact dust emission, suggesting the presence of slow shocks or hot cores in these regions. We find gas temperatures of &100 K at 0.1-pc scales based on RADEX modelling of the H2CO and NH3 lines. Although no strong correlations between temperatures and linewidths/H2O maser luminosities are found, in high-angular-resolution maps we notice several candidate shock heated regions offset from any dense cores, as well as signatures of localized heating by protostars in several dense cores. Our findings suggest that at 0.1-pc scales in this cloud star formation and strong turbulence may together affect the chemistry and temperature of the molecular gas.

Item Type: Article
Uncontrolled Keywords: astro-ph.GA; astro-ph.GA
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Q Science > QD Chemistry
Divisions: Astrophysics Research Institute
Publisher: American Astronomical Society
Related URLs:
Date Deposited: 31 Mar 2017 09:25
Last Modified: 09 Sep 2017 07:50
DOI or Identification number: 10.3847/1538-4357/aa67f7
URI: http://researchonline.ljmu.ac.uk/id/eprint/6151

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