Image restoration of high resolution observations of the M87 jet

Image-restoration techniques are applied to high-resolution (FWHM 0.5-1.0 arcsec) plates of the M87 jet obtained with the CFH telescope by Nieto and Lelievre (1982), and their description of the optical jet is confirmed. Most of the features detected are similar to those shown by the VLA map of Biretta et al. (1982), having a resolution of 0.12 arcsec. In particular, the restored images show evidence for an elongated nucleus and for a very sharp discontinuity in knot A which is not perpendicular to the jet axis. It also seems that the start of the oscillations and this discontinuity are not related. This similarity at a 0.2-arcsec scale suggests no relativistic motion (v less than 25,000 km/sec) throughout the jet.