PROPER MOTION MEASUREMENTS AND HIGH-RESOLUTION IMAGING OF THE HH-46/47 OUTFLOW

We have carried out a detailed study of the proper motions of the knots in-the HH46/47 jet and counterjet, as well as of the condensations in the associated bow shocks HH 47C and HH 47D. In the jet the tangential velocities are about 200 km s-1 with marked variations of about +/- 100 km s-1. In the other parts of the jet system the average tangential velocities are somewhat lower at 70 - 170 km s-1. Given reasonable assumptions about the pattern speed at the apex of the presumed bow shock HH47A, the orientation angle of the HH46/47 outflow with respect to the plane of the sky is found to be 34-degrees +/- 3-degrees. This enables us to correct the observed radial and tangential velocities in the jet for projection effects allowing the local flow speed of the jet and the knot pattern speed to be derived. A typical flow speed of about 300 km s-1 is found in the jet. Along part of the jet the knots at its northeastern edge are clearly moving at a lower velocity than knots closer to the jet axis. The ratio zeta between the pattern speed of the knots and the flow speed of the jet appears to show distinct phases. The components of lower tangential velocity and eventually also of lower pattern speed may be created by entrainment of the ambient material into the jet along parts of the jet channel. We coadded images taken under excellent seeing conditions into a single high-signal/noise image and deconvolved the latter using the Richardson-Lucy algorithm. The deconvolved image has a seeing of 0.47'' (FWHM) and contains a wealth of structural detail. The jet clearly shows several kinks and, most important, along most of its length consists of two well-separated bright rims. We discuss this unusual limb-brightening effect, which has only been seen in a limited number of jets so far. Proper motions were also measured for the condensations in the arc-shaped HH-objects HH 47D and HH 47C, which are assumed to be the bow shocks of the jet and the counterjet, respectively. The internal pattern of motion of these condensations is in good agreement with predictions from simple bow shock models.