A Large-Scale (CO)-C-13 Mapping of the W 49 A Molecular Cloud Complex

作者：Miyawaki Ryosuke^*; Hayashi Masahiko; Hasegawa Testuo

来源：Publications of the Astronomical Society of Japan, 2009, 61(1): 39-49.

• ISM: clouds
• ISM: H II regions
• ISM: individual (W 49 A)
• ISM: kinematics and dynamics
• stars: formation

We present (CO)-C-13 (J = 1-0) and (CO)-O-18 (J = 1-0) maps of the W 49 A molecular cloud complex observed at a resolution of 17" (HPBW). Fourteen features (MHH-1 to MHH-14) were identified in the (CO)-C-13 velocity channel maps, most of them distributed within an area of 6' (20 pc) in diameter with their total mass amounting to 1.7 x 10(6) M-circle dot). The features have a three-dimensional velocity dispersion of 8 km s(-1), which leads to a mean free time per feature of 10(6) yr. This suggests that they are interacting one another in a region of similar to 20pc in diameter. The feature MHH-1, which corresponds to W 49 N, is unique in that it exhibits a large velocity width (15 km s(-1) FWHM) and is compact in size (2.3 pc x 3.0 pc FWHM), while containing a large mass of 2.4 x 10(5) M-circle dot. This indicates that the free-fall time of MHH-1 is on the order of 10(5) yr, an order of magnitude smaller than that of the entire complex. It has turned out that MHH-1 has a smaller spatial width at V-LSR less than or similar to 8 km s(-1) than at greater than or similar to 8 km s(-1). This result, together with the line-profile characteristics of various optically thin lines, Suggests that at least two massive clouds with different radial velocities exist toward MHH-1. The massive compact feature may have been produced by the interaction of the two different velocity clouds.

• 出版日期2009
• 单位中国科学院国家天文台