High-mass star formation triggered by collision between CO filaments in N159 West in the Large Magellanic Cloud

Yasuo Fukui; Ryohei Harada; Kazuki Tokuda; Yuuki Morioka; Toshikazu Onishi; Kazufumi Torii; Akio Ohama; Yusuke Hattori; Omnarayani Nayak; Margaret Meixner; Marta Sewilo; Remy Indebetouw; Akiko Kawamura; Kazuya Saigo; Hiroaki Yamamoto; Kengo Tachihara; Tetsuhiro Minamidani; Tsuyoshi Inoue; Suzanna Madden; Maud Galametz; Vianney Lebouteiller; Norikazu Mizuno; Rosie Chen

arXiv · 1503.03540

High-mass star formation triggered by collision between CO filaments in N159 West in the Large Magellanic Cloud

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Abstract

We have carried out 13CO(J=2-1) observations of the active star-forming region N159 West in the LMC with ALMA. We have found that the CO distribution at a sub-pc scale is highly elongated with a small width. These elongated clouds called "filaments" show straight or curved distributions with a typical width of 0.5-1.0pc and a length of 5-10pc. All the known infrared YSOs are located toward the filaments. We have found broad CO wings of two molecular outflows toward young high-mass stars in N159W-N and N159W-S, whose dynamical timescale is ~10^4 yrs. This is the first discovery of protostellar outflow in external galaxies. For N159W-S which is located toward an intersection of two filaments we set up a hypothesis that the two filaments collided with each other ~10^5 yrs ago and triggered formation of the high-mass star having ~37 Mo. The colliding clouds show significant enhancement in linewidth in the intersection, suggesting excitation of turbulence in the shocked interface layer between them as is consistent with the magneto-hydro-dynamical numerical simulations (Inoue & Fukui 2013). This turbulence increases the mass accretion rate to ~6x10^-4 Mo yr^-1, which is required to overcome the stellar feedback to form the high-mass star.

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Yasuo Fukui, Ryohei Harada, Kazuki Tokuda, Yuuki Morioka, Toshikazu Onishi, Kazufumi Torii, Akio Ohama, Yusuke Hattori, Omnarayani Nayak, Margaret Meixner, Marta Sewilo, Remy Indebetouw, Akiko Kawamura, Kazuya Saigo, Hiroaki Yamamoto, Kengo Tachihara, Tetsuhiro Minamidani, Tsuyoshi Inoue, Suzanna Madden, Maud Galametz, Vianney Lebouteiller, Norikazu Mizuno, Rosie Chen. 2015-03-12. High-mass star formation triggered by collision between CO filaments in N159 West in the Large Magellanic Cloud. https://arxiv.org/abs/1503.03540

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