2021ApJ...921...23G

We present the survey of ¹²CO/¹³CO/C¹⁸O (J = 1 - 0) toward the California molecular cloud (CMC) within the region of 161.°75 <= l <= 167.°75, -9.°5 <= b <= -7.°5 using the Purple Mountain Observatory (PMO) 13.7 m millimeter telescope. Adopting a distance of 470 pc, the mass of the observed molecular cloud estimated from ¹²CO, ¹³CO, and C¹⁸O is about 2.59 x 10⁴, 0.85 x 10⁴, and 0.09 x 10⁴ M_☉, respectively. A large-scale continuous filament extending about 72 pc is revealed from the ¹³CO images. A systematic velocity gradient perpendicular to the major axis appears and is measured to be ∼0.82 km s^–1 pc^–1. The kinematics along the filament shows an oscillation pattern with a fragmentation wavelength of ∼2.3 pc and velocity amplitude of ∼0.92 km s^–1, which may be related to core-forming flows. Furthermore, assuming an inclination angle to the plane of the sky of 45°, the estimated average accretion rate is ∼101 M_☉ Myr^–1 for the cluster LkHα 101 and ∼21 M_☉ Myr^–1 for the other regions. In the C¹⁸O observations, the large-scale filament could be resolved into multiple substructures, and their dynamics are consistent with the scenario of filament formation from converging flows. Approximately 225 C¹⁸O cores are extracted, of which 181 are starless cores. Roughly 37% (67/181) of the starless cores have α_vir less than 1. Twenty outflow candidates are identified along the filament. Our results indicate active early-phase star formation along the large-scale filament in the CMC region.