L43: the late stages of a molecular outflow

Our new 21-arcsec resolution CO J = 2 --> 1 map of the L43 dark cloud shows a poorly collimated molecular outflow, with little evidence for wings at velocities greater than or similar to 10 km s(-1). The outflow appears not to be currently driven by a jet: its structure can instead be modelled as a slowly expanding shell. The shell may be compressed either by a wide-angled wind catching up with an existing shell las in the case of planetary nebulae), or by the thermal pressure of a hot low-emissivity medium interior to the shell. The outflow is most probably in a late stage of evolution, and appears to be in the process of blowing away its molecular cloud. We also present a 45-arcsec resolution CO J = 1 --> 0 map of the whole molecular cloud, showing that the outflow structure is clearly visible even in the integrated intensity of this low excitation line, and suggesting that rapid mapping may prove useful as a way of finding regions of outflow activity. We also examine the immediate surroundings of the driving source with 450 mu m imaging: this confirms that the outflow has already evacuated a bay in the vicinity of the young stellar object.