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Title: The Molecular Gas Environment in the 20 km s{sup −1} Cloud in the Central Molecular Zone

Abstract

We recently reported a population of protostellar candidates in the 20 km s{sup −1} cloud in the Central Molecular Zone of the Milky Way, traced by H{sub 2}O masers in gravitationally bound dense cores. In this paper, we report molecular line studies with high angular resolution (∼3″) 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 NH{sub 3} 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 CH{sub 3}OH, 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 modeling of the H{sub 2}CO and NH{sub 3} lines. Although no strong correlations between temperatures and linewidths/H{sub 2}O maser luminosities are found,more » in high-angular-resolution maps we note 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.« less

Authors:
;  [1]; ;  [2]; ;  [3];  [4];  [5]; ;  [6];  [7];  [8]
  1. School of Astronomy and Space Science, Nanjing University, Nanjing, Jiangsu 210093 (China)
  2. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
  3. Max Planck Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany)
  4. Astrophysics Research Institute, Liverpool John Moores University, 146 Brownlow Hill, Liverpool L3 5RF (United Kingdom)
  5. Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstraße 12-14, D-69120 Heidelberg (Germany)
  6. European Southern Observatory, Karl-Schwarzschild-Straße 2, D-85748 Garching (Germany)
  7. National Radio Astronomy Observatory, Socorro, NM 87801 (United States)
  8. Department of Physics and Astronomy, San Jose State University, One Washington Square, San Jose, CA 95192 (United States)
Publication Date:
OSTI Identifier:
22661174
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 839; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AMMONIA; CLOUDS; CORRELATIONS; DUSTS; EMISSION; LINE WIDTHS; LUMINOSITY; MASERS; METHANOL; MILKY WAY; PROTOSTARS; RESOLUTION; SILICON OXIDES; SIMULATION; STARS; TURBULENCE; WATER

Citation Formats

Lu, Xing, Gu, Qiusheng, Zhang, Qizhou, Battersby, Cara, Kauffmann, Jens, Pillai, Thushara, Longmore, Steven N., Kruijssen, J. M. Diederik, Liu, Hauyu Baobab, Zhang, Zhi-Yu, Ginsburg, Adam, and Mills, Elisabeth A. C., E-mail: xinglv.nju@gmail.com. The Molecular Gas Environment in the 20 km s{sup −1} Cloud in the Central Molecular Zone. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA67F7.
Lu, Xing, Gu, Qiusheng, Zhang, Qizhou, Battersby, Cara, Kauffmann, Jens, Pillai, Thushara, Longmore, Steven N., Kruijssen, J. M. Diederik, Liu, Hauyu Baobab, Zhang, Zhi-Yu, Ginsburg, Adam, & Mills, Elisabeth A. C., E-mail: xinglv.nju@gmail.com. The Molecular Gas Environment in the 20 km s{sup −1} Cloud in the Central Molecular Zone. United States. doi:10.3847/1538-4357/AA67F7.
Lu, Xing, Gu, Qiusheng, Zhang, Qizhou, Battersby, Cara, Kauffmann, Jens, Pillai, Thushara, Longmore, Steven N., Kruijssen, J. M. Diederik, Liu, Hauyu Baobab, Zhang, Zhi-Yu, Ginsburg, Adam, and Mills, Elisabeth A. C., E-mail: xinglv.nju@gmail.com. Mon . "The Molecular Gas Environment in the 20 km s{sup −1} Cloud in the Central Molecular Zone". United States. doi:10.3847/1538-4357/AA67F7.
@article{osti_22661174,
title = {The Molecular Gas Environment in the 20 km s{sup −1} Cloud in the Central Molecular Zone},
author = {Lu, Xing and Gu, Qiusheng and Zhang, Qizhou and Battersby, Cara and Kauffmann, Jens and Pillai, Thushara and Longmore, Steven N. and Kruijssen, J. M. Diederik and Liu, Hauyu Baobab and Zhang, Zhi-Yu and Ginsburg, Adam and Mills, Elisabeth A. C., E-mail: xinglv.nju@gmail.com},
abstractNote = {We recently reported a population of protostellar candidates in the 20 km s{sup −1} cloud in the Central Molecular Zone of the Milky Way, traced by H{sub 2}O masers in gravitationally bound dense cores. In this paper, we report molecular line studies with high angular resolution (∼3″) 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 NH{sub 3} 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 CH{sub 3}OH, 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 modeling of the H{sub 2}CO and NH{sub 3} lines. Although no strong correlations between temperatures and linewidths/H{sub 2}O maser luminosities are found, in high-angular-resolution maps we note 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.},
doi = {10.3847/1538-4357/AA67F7},
journal = {Astrophysical Journal},
number = 1,
volume = 839,
place = {United States},
year = {Mon Apr 10 00:00:00 EDT 2017},
month = {Mon Apr 10 00:00:00 EDT 2017}
}