Interaction Between HII Region and AFGL333-Ridge: Implications to the Star Formation Scenario

Abstract

We investigated the star formation activities in the AFGL333 region, which is in the vicinity of the W4 expanding bubble, by conducting NH3 (1,1), (2,2), and (3,3) mapping observations with the 45 m Nobeyama Radio Telescope at an angular resolution of 75". The morphology of the NH3 (1,1) map shows a bow-shape structure with the size of 2.0 x 0.6 pc as seen in the dust continuum. At the interface between the W4 bubble and the dense NH3 cloud, the compact HII region G134.2+0.8, associated with IRAS02245+6115, is located. Interestingly, just north and south of G134.2+0.8 we found NH3 emission exhibiting large velocity widths of ~ 2.8 km/s, compared to 1.8 km/s at the other positions. As the possibility of mechanical energy injection through the activity of YSO(s) is low, we considered the origin of the large turbulent gas motion as indication of interaction between the compact HII region and the periphery of the dense molecular cloud. We also found expanding motion of the CO emission associated with G134.2+0.8. The overall structure of the AFGL333-Ridge might have been formed by the expanding bubble of W4. However, the small velocity widths observed west of IRAS02245+6115, around the center of the dense molecular cloud, suggest that interaction with the compact HII region is limited. Therefore the YSOs (dominantly Class 0/I) in the core of the AFGL333-Ridge dense molecular cloud most likely formed in quiescent mode. As has been previously suggested for the large scale star formation in the W3 giant molecular cloud, our results show an apparent coexistence of induced and quiescent star formation in this region. It appears that star formation in the AFGL333 region has proceeded without significant external triggers, but accompanying stellar feedback environment.

27 pages, 15 figures, 3 tables, accepted for publication in PASJ

References in corpus (6)

• The SCUBA Legacy Catalogue: Continuum Objects Detected by SCUBA
• Water maser motions in W3(OH) and a determination of its distance
• The dangers of being trigger--happy
• The Diverse Stellar Populations of the W3 Star Forming Complex
• The star-forming content of the W3 giant molecular cloud
• Herschel Observations of the W3 GMC: Clues to the Formation of Clusters of High-Mass Stars

Cited by in corpus (4)

• CO Outflow Candidates Toward the W3/4/5 Complex I: The Sample and its Spatial Distribution
• Ammonia mapping observations toward the Galactic massive star-forming region Sh 2-255 and Sh 2-257
• Ammonia mapping observations of the Galactic infrared bubble N49: Three NH${}_3$ clumps along the molecular filament
• KAgoshima Galactic Object survey with Nobeyama 45-metre telescope by Mapping in Ammonia lines (KAGONMA): Star formation feedback on dense molecular gas in the W33 complex