ASIAA: Molecular Gas Arms Seen As Cradles of Star Formation

[bystander]

Giant Spiraling Molecular Gas Arms as Cradles of Dense Massive Molecular Cores
Academia Sinica Institute of Astronomy and Astrophysics | 2015 May 20

[img3="An overview of massive stellar cluster-forming molecular cloud from numerical hydrodynamical simulations (courtesy of James Dale), and ALMA observations for the deeply embedded central few light-years region. The ALMA observations for the first time resolve the giant spiral arms, which harbor abundant dense molecular cores.
(Credit: ALMA (ESO/NAOJ/NRAO), H. B. Liu, J. Dale)"]http://www.almaobservatory.org/images/n ... liu_02.jpg[/img3]

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A research team led by Dr. Hauyu Liu at the Institute of Astronomy and Astrophysics, Academia Sinica (ASIAA) observed the luminous OB cluster-forming massive molecular clump G33.92+0.11 with the Atacama Large Millimeter/submillimeter Array (ALMA), and unveiled the fine molecular gas structures deeply embedded at the center of the parent molecular cloud. This finding provides a greatly simplified picture of overall cloud geometry and kinematics, which represents a crucial step forward in the understanding of the upper end of the stellar and molecular core mass functions. ...

Via ALMA observations, this research for the first time resolved an embedded giant coherent dense gas structure on a several light-year scale. Surprisingly, this dense gas structure presents several spiral arms, which appear like a version of the previously observed spiral arms surrounding the low-mass protobinary, scaled-up by a factor of ~10³. These giant spiral arms, and the massive molecular gas cores located at their convergence, are cradles to form the highest mass stars in this stellar cluster.

How the young massive stellar clusters (YMCs) and globular clusters (GCs) come into existence, remains a fundamental question in astrophysics. To form such complex systems, it is necessary for massive amounts of gas to be converted into stars with little loss before they start to disperse the gas by the action of their winds—so-called stellar feedback—and such a process is far from trivial. The formation of these systems likely requires a special geometry and dynamical evolution of the natal molecular cloud. ...

ALMA Reveals the Cradles of Dense Cores: the Birthplace of Massive Stars
Atacama Large Millimeter/submillimeter Array (ALMA) | 2015 May 19

ALMA resolves the spiraling accretion flow in the luminous OB cluster forming region G33.92+0.11 - Hauyu Baobab Liu et al

• Astrophysical Journal 804(1) 37 (2015 May 01) DOI: 10.1088/0004-637X/804/1/37
  arXiv.org > astro-ph > arXiv:1505.04255 > 16 May 2015