A wide-field CO survey towards the California Molecular Filament
  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.
