MOLECULAR CLOUDS TOWARD RCW49 AND WESTERLUND 2: EVIDENCE FOR CLUSTER FORMATION TRIGGERED BY CLOUD–CLOUD COLLISION

By N. Furukawa, J. Dawson, A. Ohama, A. Kawamura, N. Mizuno, T. Onishi, Yasuo Fukui. 2009

145 citations recorded by the source corpus.

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.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/aa1690a7bab5f76207d2157dc5af51b200f7b863

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

1. R. Leaman
2. Y. Fukui
3. D. VandenBerg
4. J. Trevor Mendel
5. Tsuyoshi Inoue
6. A. Kawamura
7. T. Onishi
8. N. Mizuno

In Instrumentation

1. R. Leaman
2. J. Trevor Mendel
3. A. Kawamura
4. Y. Fukui
5. N. Mizuno
6. D. VandenBerg
7. Debra A. Fischer
8. J. Valenti

Citations in the corpus

• The bifurcated age–metallicity relation of Milky Way globular clusters and its implications for the accretion history of the galaxy (2013, background): “If massive GCs are necessarily formed in very intense starbursts (Elmegreen, Malhotra & Rhoads 2012) or massive GMC collisions (Furukawa et al. 2009), it could simply mean that these conditions are not found in dwarf galaxies or the MW (which shows a relatively quiescent SFH).”
• MOLECULAR CLOUDS TOWARD THE SUPER STAR CLUSTER NGC 3603; POSSIBLE EVIDENCE FOR A CLOUD–CLOUD COLLISION IN TRIGGERING THE CLUSTER FORMATION (2013, background): “– 25 – – 26 – – 27 – – 28 – – 29 – – 30 – – 31 – – 32 – – 33 – – 34 – – 35 – – 36 – – 38 – (2008); 7, Clark et al. (2010, 2005); reference2 shows paper of molecular clouds; 8 Furukawa et al. (2009b); Ohama et al. (2010) – 39 – – 40 – Note.”
• FORMATION OF MASSIVE MOLECULAR CLOUD CORES BY CLOUD–CLOUD COLLISION (2013, background): “NANTEN2 observations discovered two more cases of massive star formation by similar cloud-cloud collisions in Westerlund 2 (Furukawa et al, 2009; Ohama et al. 2010) and in M20 (Torii et al. 2011), suggesting the importance of such triggering in massive star formation.”