2022RAA....22d5008L

We present a large-scale simultaneous survey of the CO isotopologues (¹²CO, ¹³CO, and C¹⁸O) J = 1-0 line emission toward the Galactic plane region of l = 106.°65 to 109.°50 and b = -1.°85 to 0.°95 using the Purple Mountain Observatory 13.7 m millimeter-wavelength telescope. Except for the molecular gas in the solar neighborhood, the emission from the molecular gas in this region is concentrated in the velocity range of [-60, -35] km s^–1. The gas in the region can be divided into four clouds, with mass in the range of ∼10³-10⁴M_☉. We have identified 25 filaments based on the ¹³CO data. The median excitation temperature, length, line mass, line width, and virial parameter of the filaments are 10.89 K, 8.49 pc, 146.11 M_☉ pc^–1, 1.01 km s^–1, and 3.14, respectively. Among these filaments, eight have virial parameters of less than 2, suggesting that they are gravitationally bound and can lead to star formation. Nineteen H II regions or candidates have previously been found in the region and we investigate the relationships between these H II regions/candidates and surrounding molecular clouds in detail. Using morphology similarity and radial velocity consistency between H II regions/candidates and molecular clouds as evidence for association, and raised temperature and velocity broadening as signatures of interaction, we propose that 12 H II regions/candidates are associated with their surrounding molecular clouds. In the case of the H II region of S142, the energy of the H II region is sufficient to maintain the turbulence in the surrounding molecular gas.