TY - JOUR
T1 - ALMA view of the Galactic super star cluster RCW 38 at 270 au resolution
AU - Torii, Kazufumi
AU - Tokuda, Kazuki
AU - Tachihara, Kengo
AU - Onishi, Toshikazu
AU - Fukui, Yasuo
N1 - Funding Information:
This paper makes use of the following ALMA data: ADS/JAO.ALMA#2015.1.01134.S. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), MOST and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ. The authors thank Dr. Takashi Hosokawa for a valuable discussion. This work was financially supported by Grants-in-Aid for Scientific Research (KAKENHI) of the Japanese society for the Promotion of Science (JSPS; grant numbers 18H05440, 18K13582, 15K17607, 15H05694, 24224005, and 26247026), and NAOJ ALMA Scientific Research Grant Number 2016-03B. We thank the anonymous referee for helpful comments, which significantly improved the manuscript.
Funding Information:
This paper makes use of the following ALMA data: ADS/ JAO.ALMA#2015.1.01134.S. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), MOST and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ. The authors thank Dr. Takashi Hosokawa for a valuable discussion. This work was financially supported by Grants-in-Aid for Scientific Research (KAKENHI) of the Japanese society for the Promotion of Science (JSPS; grant numbers 18H05440, 18K13582, 15K17607, 15H05694, 24224005, and 26247026), and NAOJ ALMA Scientific Research Grant Number 2016-03B. We thank the anonymous referee for helpful comments, which significantly improved the manuscript.
Publisher Copyright:
© The Author(s) 2021. Published by Oxford University Press on behalf of the Astronomical Society of Japan.
PY - 2021/2/1
Y1 - 2021/2/1
N2 - We report millimeter/submillimeter continuum and molecular line observations of the Galactic super star cluster RCW 38, obtained from the Atacama Large Millimeter/Submillimeter Array with a minimum angular resolution of 0.''17 × 0.''15 (≃ 289 au × 255 au). The C18O image reveals many massive condensations embedded within filamentary structures extending along the northwest-southeast direction in the center of cluster. The condensations have sizes of 0.01-0.02 pc, H2 column densities of 1023-1024 cm−2, and H2 masses of 10-130 M⊙. In addition, the 233 GHz continuum image reveals two dense, small millimeter-sources with radii of 460 and 200 au (Source A and Source B). Source A is embedded within the most massive C18O condensation, whereas no counterpart is seen for Source B. The masses of Source A and Source B are estimated as 13 and 3 M⊙ at the optically thin limit, respectively. The C18O emission shows a velocity gradient of 2 km s−1 at the central 2000 au of Source A, which could be interpreted as a Keplerian rotation with a central mass of a few M⊙ or infall motion of gas. Further, the ALMA 12CO data reveal that Source A and Source B are associated with molecular outflows exhibiting maximum velocities of ∼30-70 km s−1. The outflows have short dynamical timescales of <1000 yr and high-mass outflow rates of ∼10−4-10−3 M⊙ yr−1. These observational signatures suggest an early evolutionary phase of the massive star formation in Source A and Source B.
AB - We report millimeter/submillimeter continuum and molecular line observations of the Galactic super star cluster RCW 38, obtained from the Atacama Large Millimeter/Submillimeter Array with a minimum angular resolution of 0.''17 × 0.''15 (≃ 289 au × 255 au). The C18O image reveals many massive condensations embedded within filamentary structures extending along the northwest-southeast direction in the center of cluster. The condensations have sizes of 0.01-0.02 pc, H2 column densities of 1023-1024 cm−2, and H2 masses of 10-130 M⊙. In addition, the 233 GHz continuum image reveals two dense, small millimeter-sources with radii of 460 and 200 au (Source A and Source B). Source A is embedded within the most massive C18O condensation, whereas no counterpart is seen for Source B. The masses of Source A and Source B are estimated as 13 and 3 M⊙ at the optically thin limit, respectively. The C18O emission shows a velocity gradient of 2 km s−1 at the central 2000 au of Source A, which could be interpreted as a Keplerian rotation with a central mass of a few M⊙ or infall motion of gas. Further, the ALMA 12CO data reveal that Source A and Source B are associated with molecular outflows exhibiting maximum velocities of ∼30-70 km s−1. The outflows have short dynamical timescales of <1000 yr and high-mass outflow rates of ∼10−4-10−3 M⊙ yr−1. These observational signatures suggest an early evolutionary phase of the massive star formation in Source A and Source B.
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U2 - 10.1093/pasj/psaa115
DO - 10.1093/pasj/psaa115
M3 - Article
AN - SCOPUS:85120299247
SN - 0004-6264
VL - 73
SP - 205
EP - 219
JO - Publication of the Astronomical Society of Japan
JF - Publication of the Astronomical Society of Japan
IS - 1
ER -