FOREST Unbiased Galactic plane Imaging survey with the Nobeyama 45 m telescope (FUGIN): Molecular clouds toward W 33; possible evidence for a cloud–cloud collision triggering O star formation

PASJ: Publications of the Astronomical Society of Japan

Minamidani, Tetsuhiro¹  Fujita, Shinji¹  Ohama, Akio²  Hattori, Yusuke²  Matsuo, Mitsuhiro³  Kohno, Mikito³  Yamagishi, Mitsuyoshi³  Tachihara, Kengo³  Fukui, Yasuo³  Yamamoto, Hiroaki³  Kuno, Nario⁴  Kuriki, Mika⁵  Tsuda, Yuya⁶  Umemoto, Tomofumi⁶  Torii, Kazufumi⁶  Nishimura, Atsushi⁶  Sano, Hidetoshi⁷ 

[1] Department of Astronomical Science, School of Physical Science, SOKENDAI (The Graduate University for Advanced Studies), 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan;Department of Physics, Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Ten-nodai, Tsukuba, Ibaraki 305-8577, Japan;Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan;Graduate School of Science and Engineering, Meisei University, 2-1-1 Hodokubo, Hino, Tokyo 191-0042, Japan;Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210, Japan;Nobeyama Radio Observatory, National Astronomical Observatory of Japan (NAOJ), National Institutes of Natural Sciences (NINS), 462-2 Nobeyama, Minamimaki, Minamisaku, Nagano 384-1305, Japan;Tomonaga Center for the History of the Universe, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan

关键词: stars: formation;    ISM: clouds;    ISM: molecules;   

DOI  :  10.1093/pasj/psx137

学科分类：天文学(综合)

来源: Oxford University Press

【 摘 要 】

We observed molecular clouds in the W 33 high-mass star-forming region associated with compact and extended H ii regions using the NANTEN2 telescope as well as the Nobeyama 45 m telescope in the J = 1–0 transitions of 12CO, 13CO, and C18O as part of the FOREST Unbiased Galactic plane Imaging survey with the Nobeyama 45 m telescope (FUGIN) legacy survey. We detected three velocity components at 35 km s−1, 45 km s−1, and 58 km s−1. The 35 km s−1 and 58 km s−1 clouds are likely to be physically associated with W 33 because of the enhanced 12CO J = 3–2 to J = 1–0 intensity ratio as |$R_{\rm 3\mbox{-}2/1\mbox{-}0} > 1.0$| due to the ultraviolet irradiation by OB stars, and morphological correspondence between the distributions of molecular gas and the infrared and radio continuum emissions excited by high-mass stars. The two clouds show complementary distributions around W 33. The velocity separation is too large to be gravitationally bound, and yet not explained by expanding motion by stellar feedback. Therefore, we discuss whether a cloud–cloud collision scenario likely explains the high-mass star formation in W 33.

【 授权许可】

CC BY