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