Multi-scale analysis of the Monoceros OB 1 star-forming region: II.
  Colliding filaments in the Monoceros OB1 molecular cloud
  We started a multi-scale analysis of G202.3+2.5, an intertwined filamentary
region of Monoceros OB1. In Paper I, we examined the distributions of dense
cores and protostars and found enhanced star formation (SF) activity in the
junction region of the filaments. In this second paper, we aim to unveil the
connections between the core and filament evolutions, and between the filament
dynamics and the global evolution of the cloud. We characterise the gas
dynamics and energy balance using Herschel and WISE observations and molecular
tracers observed with the IRAM 30m and TRAO 14m telescopes. The velocity field
of the cloud is examined and velocity-coherent structures are put in
perspective with the cloud environment. Two main velocity components (VCs) are
revealed, well separated in the north and merged around the location of intense
N2H+ emission where Paper I found the peak of SF activity. The relative
position of the two VCs along the sightline, and the velocity gradient in N2H+
emission imply that the VCs have been undergoing collision for ~10^5 yrs. The
dense gas where N2H+ is detected is interpreted as the compressed region
between the two filaments, which corresponds to a high mass inflow rate of
~1e-3 Msun/yr and possibly leads to an increase in its SF efficiency. We
identify a protostar in the junction region that possibly powers two crossed
intermittent outflows. We show that the HII region around the nearby cluster
NCG 2264 is still expanding and its role in the collision is examined. However,
we cannot rule out the idea that the collision arises mostly from the global
collapse of the cloud. The (sub-)filament-scale observables examined in this
paper reveal a collision between G202.3+2.5 sub-structures and its probable
role in feeding the cores in the junction region. One must now characterise the
cloud morphology, its fragmentation, and magnetic field, all at high
resolution.
