A Multi-wavelength Study on the Formation of AFGL 333-Ridge
  We presented a multi-wavelength study of AFGL 333-Ridge. The molecular line
data reveals that the AFGL 333-Ridge has two independent velocity components at
-50.5 km/s and -48.0 km/s. In the Position-Velocity diagram, the bridge feature
connects with two parts that are spatially correlated but separated in
velocity. These observational evidences support the scenario that the two
velocity components have collided and merged into one molecular cloud. The
majority of Class I YSOs are distributed within the collision region,
suggesting that the cloud-cloud collision has induced the YSOs formation in the
ridge. Using the radio recombination line (RRL) data obtained by the
Five-hundred-meter Aperture Spherical radio Telescope (FAST), the RRL
velocities of three HII regions are consistent with that of the AFGL 333-Ridge.
By comparing the three HII regions' dynamical ages with the collision timescale
of the two components, we conclude that the influence of the three HII regions
may not drive the two clouds to merge. The formation of the AFGL 333-Ridge is
probably due to the expansion of the giant HII region W4.
