In order to understand the formation of massive OB stars , we report a multi-wavelength observational study of a giant molecular cloud hosting the S147/S153 complex ( size \sim 90 pc \times 50 pc ) .
The selected complex is located in the Perseus arm , and contains at least five H ii regions ( S147 , S148 , S149 , S152 , and S153 ) powered by massive OB stars having dynamical ages of \sim 0.2 – 0.6 Myr .
The Canadian Galactic Plane Survey ^ { 12 } CO line data ( beam size \sim 100 ^ { { } ^ { \prime \prime } } .4 ) trace the complex in a velocity range of [ - 59 , - 43 ] km s ^ { -1 } , and also reveal the presence of two molecular cloud components around - 54 and - 49 km s ^ { -1 } in the direction of the complex .
Signatures of the interaction/collision between these extended cloud components are investigated through their spatial and velocity connections .
These outcomes suggest the collision of these molecular cloud components about 1.6 Myr ago .
Based on the observed overlapping zones of the two clouds , the collision axis appears to be parallel to the line-of-sight .
Deep near-infrared photometric analysis of point-like sources shows the distribution of infrared-excess sources in the direction of the overlapping zones of the molecular cloud components , where all the H ii regions are also spatially located .
All elements put together , the birth of massive OB stars and embedded infrared-excess sources seems to be triggered by two colliding molecular clouds in the selected site .
High resolution observations of dense gas tracer will be required to further confirm the proposed scenario .