Fibers in the NGC1333 proto-cluster
  Are the initial conditions for clustered star formation the same as for
non-clustered star formation? To investigate the initial gas properties in
young proto-clusters we carried out a comprehensive and high-sensitivity study
of the internal structure, density, temperature, and kinematics of the dense
gas content of the NGC1333 region in Perseus, one of the nearest and best
studied embedded clusters. The analysis of the gas velocities in the
Position-Position-Velocity space reveals an intricate underlying gas
organization both in space and velocity. We identified a total of 14
velocity-coherent, (tran-)sonic structures within NGC1333, with similar
physical and kinematic properties than those quiescent, star-forming (aka
fertile) fibers previously identified in low-mass star-forming clouds. These
fibers are arranged in a complex spatial network, build-up the observed total
column density, and contain the dense cores and protostars in this cloud. Our
results demonstrate that the presence of fibers is not restricted to low-mass
clouds but can be extended to regions of increasing mass and complexity. We
propose that the observational dichotomy between clustered and non-clustered
star-forming regions might be naturally explained by the distinct spatial
density of fertile fibers in these environments.
