2017ApJ...837..154N

We present the results of wide-field ¹²CO (J=2–1) and ¹³CO (J=2–1) observations toward the Aquila Rift and Serpens molecular cloud complexes (25^○l33^○ and 1^○b6^○) at an angular resolution of 3.'4 (~0.25 pc) and at a velocity resolution of 0.079 km s^–1 with velocity coverage of -5 km s^–1 V_LSR 35 km s^–1. We found that the ¹³CO emission better traces the structures seen in the extinction map, and derived the X_^13CO-factor of this region. Applying SCIMES to the ¹³CO data cube, we identified 61 clouds and derived their mass, radii, and line widths. The line width-radius relation of the identified clouds basically follows those of nearby molecular clouds. The majority of the identified clouds are close to virial equilibrium, although the dispersion is large. By inspecting the ¹²CO channel maps by eye, we found several arcs that are spatially extended to 0.°2-3° in length. In the longitude-velocity diagrams of ¹²CO, we also found two spatially extended components that appear to converge toward Serpens South and the W40 region. The existence of two components with different velocities and arcs suggests that large-scale expanding bubbles and/or flows play a role in the formation and evolution of the Serpens South and W40 cloud.