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 ∼100 lower mass stars within a 0.3 pc radius toward (l,b)∼ (350.∘5, 0.∘96), close to the Galactic min-starburst NGC 6334. We found two velocity components associated with the cluster by new observations of 12CO 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 ∼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.
@article{arxiv.1706.05768,
title = {Formation of the young compact cluster GM 24 triggered by a cloud-cloud collision},
author = {Yasuo Fukui and Mikito Kohno and Keiko Yokoyama and Atsushi Nishimura and Kazufumi Torii and Yusuke Hatorri and Hidetoshi Sano and Akio Ohama and Hiroaki Yamamoto and Kengo Tachihara},
journal= {arXiv preprint arXiv:1706.05768},
year = {2018}
}
Comments
13 pages, 7 figures, 3 tables, accepted for publication in PASJ