First Embedded Cluster Formation in California Molecular Cloud

We performed a multi-wavelength observation toward the LkHα 101 embedded cluster and its adjacent 85'×60' region. The LkHα 101 embedded cluster is the first and only significant cluster in the California molecular cloud (CMC). These observations have revealed that the LkHα 101 embedded cluster is located just at the projected intersectional region of two filaments. One filament is the highest-density section of the CMC, the other is a new identified filament with a low-density gas emission. Toward the projected intersection, we find the bridging features connecting the two filaments in velocity, and identify a V-shaped gas structure. These agree with the scenario that the two filaments are colliding with each other. Using the Five-hundred-meter Aperture Spherical radio Telescope, we measured the radio recombination line velocity of the LkHα 101 H ii region to be 0.5 km s−1, which is related to the velocity component of the CMC filament. Moreover, there are some young stellar objects (YSOs) distributed outside the intersectional region. We suggest that the cloud–cloud collision, together with the fragmentation of the main filament, may play an important role in the YSOs' formation of the cluster.