Artefacts in the deconvolution of images of E-S0 galaxies

¹ Observatoire de la Côte d'Azur, Dept. Augustin Fresnel, B.P. 229, F-06304 Nice Cedex 4, France
² Observatoire de Paris, DEMIRM, 77 av. Denfert-rochereau, F-75014 Paris, France

Send offprint request to: R. Michard

Received: 11 August 1995
Accepted: 27 November 1995

Abstract

Unexpected circumnuclear isophotal structures were observed during tests of Lucy's deconvolution technique, performed upon high resolution CFHT frames. They contain an enhanced nuclear disk surrounded by a “boxy" ring; an upward hump in ellipticity corresponds with this ring. Such structures are produced in the deconvolution of synthetic images having large enough surface brightness gradients and ellipticities, as is the case for two of our test galaxies. Similar stuctures occur in convolving and deconvolving model galaxies with a model of the HST's PSF prior to the telescope renovation, but they are limited in radial extent up to less than 1 arcsec of isophotal major axis. If the deconvolution is performed with a PSF differing somewhat from the one used in the convolution, large and far extending artefacts can occur.