ARTIFACTS IN THE DECONVOLUTION OF IMAGES OF E-SO GALAXIES

Unexpected circumnuclear isophotal structures were observed during tes ts of Lucy's deconvolution technique, performed upon high resolution C FHT frames. They contain an enhanced nuclear disk surrounded by a ''bo xy'' ring; an upward hump in ellipticity corresponds with this ring. S uch structures are produced in the deconvolution of synthetic images h aving large enough surface brightness gradients and ellipticities, as is the case for two of our test galaxies. Similar stuctures occur in c onvolving and deconvolving model galaxies with a model of the HST's PS F prior to the telescope renovation, but they are limited in radial ex tent up to less than 1 arcsec of isophotal major axis. If the deconvol ution is performed with a PSF differing somewhat from the one used in the convolution, large and far extending artefacts can occur.