2009/04/02 by N. Furukawa, Naoko Furukawa, J. R. Dawson +11 · 8 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Stellar, planetary, and galactic studies #astro-ph.GA
paper · pdf · doi:10.1088/0004-637x/696/2/l115
A version with higher resolution figures is available from http://www.a.phys.nagoya-u.ac.jp/~naoko/research/apjl2009/fur09_rev_highreso.pdf
arxiv created 2009/04/02 · openalex publication_date 2009/04/17 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
We have made CO( J = 2–1) observations toward the H ii region RCW 49 and its ionizing source, the rich stellar cluster Westerlund 2, with the NANTEN2 submillimeter telescope. These observations have revealed that two molecular clouds in velocity ranges of −11 to +9 km s −1 and 11 to 21 km s −1 , respectively, show remarkably good spatial correlations with the Spitzer IRAC mid-infrared image of RCW 49, as well a velocity structures indicative of localized expansion around the bright central regions and stellar cluster. This strongly suggests that the two clouds are physically associated with RCW 49. We obtain a new kinematic distance estimate to RCW 49 and Wd2 of 5.4 +1.1 −1.4 kpc, based on the mean velocity and velocity spread of the associated gas. We argue that the acceleration of the gas by stellar winds from Westerlund 2 is insufficient to explain the entire observed velocity dispersion of the molecular gas, and suggest a scenario in which a collision between the two clouds ∼4 Myr ago may have triggered the formation of the stellar cluster.