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arXiv · 1706.05768

Formation of the young compact cluster GM 24 triggered by a cloud-cloud collision

Yasuo Fukui·Mikito Kohno·Keiko Yokoyama·Atsushi Nishimura·Kazufumi Torii·Yusuke Hatorri·Hidetoshi Sano·Akio Ohama·Hiroaki Yamamoto·Kengo Tachihara
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Abstract

High-mass star formation is an important step which controls galactic evolution. GM 24 is a heavily obscured star cluster including a single O9 star with more than $\sim$100 lower mass stars within a 0.3 pc radius toward $(l,b)\sim$ (350.$^{\circ}$5, 0.$^{\circ}$96), close to the Galactic min-starburst NGC 6334. We found two velocity components associated with the cluster by new observations of $^{12}$CO $J=$ 2-1 emission, whereas the cloud was previously considered to be single. We found the distribution of the two components of $5$ km s$^{-1}$ separation shows complementary distribution which fits well with each other, if a relative displacement of 3 pc is applied along the Galactic plane. A position-velocity diagram of the GM 24 cloud is explained by a model based on the numerical simulations of two colliding clouds, where an intermediate velocity component created by collision is taken into account. We estimate the collision time scale to be $\sim$Myr in projection of a relative motion titled to the line of sight by 45 degrees. The results lend further support for cloud-cloud collision as a major mechanism of high-mass star formation in the Carina-Sagittarius Arm.

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Yasuo Fukui, Mikito Kohno, Keiko Yokoyama, Atsushi Nishimura, Kazufumi Torii, Yusuke Hatorri, Hidetoshi Sano, Akio Ohama, Hiroaki Yamamoto, Kengo Tachihara. 2017-11-13. Formation of the young compact cluster GM 24 triggered by a cloud-cloud collision. https://doi.org/10.1093/pasj%2Fpsx144

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