ALMA resolves the spiraling accretion flow in the luminous OB cluster-forming region G33.92+0.11

Journal Article · Fri May 01 04:00:00 EDT 2015 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/804/1/37· OSTI ID:22883248

Liu, Hauyu Baobab; Chen, Huei-Ru ^[1]; Galván-Madrid, Roberto ^[2]; Jiménez-Serra, Izaskun ^[3]; Román-Zúñiga, Carlos ^[4]; Zhang, Qizhou ^[5]; Li, Zhiyun ^[6]

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1. Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 106, Taiwan (China)
2. Centro de Radioastronomía y Astrofísica, UNAM, A.P. 3-72, Xangari, Morelia 58089 (Mexico)
3. European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching (Germany)
4. Instituto de Astronomía, UNAM, Unidad Académica en Ensenada, Ensenada 22860 (Mexico)
5. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
6. Department of Astronomy, P.O. Box 400325, Charlottesville, VA 22904 (United States)

How rapidly collapsing parsec-scale massive molecular clumps feed high-mass stars and how they fragment to form OB clusters have been outstanding questions in the field of star formation. In this work, we report the resolved structures and kinematics of the approximately face-on, rotating massive molecular clump, G33.92+0.11. Our high-resolution Atacama Large Millimeter/submillimeter Array images show that the spiral arm-like gas overdensities form in the eccentric gas accretion streams. First, we resolved that the dominant part of the ∼0.6 pc scale massive molecular clump (3.0{sub −1.4}{sup +2.8}·10{sup 3} M{sub ⊙}) G33.92+0.11 A is tangled with several 0.5–1 pc size molecular arms spiraling around it, which may be connected further to exterior gas accretion streams. Within G33.92+0.11 A, we resolved the ∼0.1 pc width gas mini-arms connecting to the two central massive (100–300 M{sub ⊙}) molecular cores. The kinematics of arms and cores elucidate a coherent accretion flow continuing from large to small scales. We demonstrate that the large molecular arms are indeed the cradles of dense cores, which are likely current or future sites of high-mass star formation. Since these deeply embedded massive molecular clumps preferentially form the highest-mass stars in the clusters, we argue that dense cores fed by or formed within molecular arms play a key role in making the upper end of the stellar and core mass functions.

• OSTI ID: 22883248
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 804; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United Kingdom
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
LUMINOSITY
MASS
RESOLUTION
STAR EVOLUTION
STARS