New insights in giant molecular cloud hosting the S147/S153 complex: signatures of interacting clouds
Abstract 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 ${\sim}90\:\:\mbox{pc} \times 50\:$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 with dynamical ages ${\sim}0.2$–$0.6\:$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 the dense gas tracer will be required to further confirm the proposed scenario.