Clustered star formation in W75 N

We present 2″-7″ resolution 3 mm continuum and CO(J = 1-0) line emission and near-infrared K_s, H₂, and [Fe II] images toward the massive star-forming region W75 N. The CO emission uncovers a complex morphology of multiple, overlapping outflows. A total flow mass of greater than 255 M_⊙ extends 3 pc from end to end and is being driven by at least four late to early-B protostars. More than 10% of the molecular cloud has been accelerated to high velocities by the molecular flows (>5.2 km s^-1 relative to v_LSR and the mechanical energy in the outflowing gas is roughly half the gravitational binding energy of the cloud. The W75 N cluster members represent a range of evolutionary stages, from stars with no apparent circumstellar material to deeply embedded protostars that are actively powering massive outflows. Nine cores of millimeter-wavelength emission highlight the locations of embedded protostars in W75 N. The total mass of gas and dust associated with the millimeter cores ranges from 340 to 11 M_⊙. The infrared reflection nebula and shocked H₂ emission have multiple peaks and extensions which, again, suggests the presence of several outflows. Diffuse H₂ emission extends about 0.6 pc beyond the outer boundaries of the CO emission while the [Fe II] emission is only detected close to the protostars. The infrared line emission morphology suggests that only slow, nondissociative J-type shocks exist throughout the parsec-scale outflows. Fast, dissociative shocks, common in jet-driven low-mass outflows, are absent in W75 N. Thus, the energetics of the outflows from the late to early B protostars in W75 N differ from their low-mass counterparts - they do not appear to be simply scaled-up versions of low-mass outflows.