We present the survey of $^{12}$CO/$^{13}$CO/C$^{18}$O (J=1-0) toward the California Molecular Cloud (CMC) within the region of 161.75$^{circ} leqslant l leqslant$ 167.75$^{circ}$,-9.5$^{circ} leqslant b leqslant $-7.5$^{circ}$, 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 $^{12}$CO, $^{13}$CO, and C$^{18}$O is about 2.59$times$10$^{4}$ M$_odot$, 0.85$times$10$^{4}$ M$_odot$, and 0.09$times$10$^{4}$ M$_odot$, respectively. A large-scale continuous filament extending about 72 pc is revealed from the $^{13}$CO images. A systematic velocity gradient perpendicular to the major axis appears and is measured to be $sim$ 0.82 km s$^{-1}$ pc$^{-1}$. The kinematics along the filament shows an oscillation pattern with a fragmentation wavelength of $sim$ 2.3 pc and velocity amplitude of $sim$ 0.92 km s$^{-1}$, which may be related with core-forming flows. Furthermore, assuming an inclination angle to the plane of the sky of 45$^{circ}$, the estimated average accretion rate is $sim$ 101 M$_odot$ Myr$^{-1}$ for the cluster LkH$alpha$ 101 and $sim$ 21 M$_odot$ Myr$^{-1}$ for the other regions. In the C$^{18}$O 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 C$^{18}$O cores are extracted, of which 181 are starless cores. Roughly 37$%$ (67/181) of the starless cores have $alpha_{text{vir}}$ 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.
تحميل البحث