Submillimetre and near-infrared observations of L1448: a curving Formula jet with multiple bow shocks

A high-resolution ($$0.6 \ {\rm arcsec \ pixel}^{-1}$$), narrow-band, $${\rm H}_2 \ v=1-0 \ {\rm S}(1)$$ image of the high-velocity CO outflow in L1448 reveals a remarkable jet-like structure. The coincidence of this $${\rm H}_2$$ jet with the CO bipolar outflow implies a close association between the two phenomena. The $${\rm H}_2$$ jet comprises a series of knots, and three bow-shaped features equally spaced along the jet length, which we associate with the sporadic nature of this outflow. K-band imaging of the source also shows a conical reflection nebula extending towards the $${\rm H}_2$$ jet structure, whilst maps in $${\rm HCO}^+ \ J=3-2$$ and $${\rm CS} \ J=5-4$$ show two peaks, one towards the source of the $${\rm H}_2$$ jet and CO outflow, and the other towards the infrared source IRS 3 situated to the north of this region. Together these observations suggest that the $${\rm H}_2$$ jet represents the shock interface between a stellar wind from the L1448-mm source and the surrounding molecular gas, although the CO outflow is not thought to be dependent on this interaction.