Based on observations at the TIRGO, NOT, and VATT telescopes. TIRGO (Gornergrat, CH) is operated by CAISMI-CNR, Arcetri, Firenze. NOT (La Palma, Canary Islands) is operated by NOTSA, the Nordic Observatory Scientific Association. VATT (Mt. Graham, Az) is operated by VORG, the Vatican Observatory Research Group.

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Table 3 and Fig. 4 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html. Radial profiles in tabular form and images FITS files are also available upon request from gmorio@arcetri.astro.it.

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...packages

IRAF is the Image Analysis and Reduction Facility made available to the astronomical community by the National Optical Astronomy Observatories, which are operated by AURA, Inc., under contract with the U.S. National Science Foundation. STSDAS is distributed by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under NASA contract NAS 5-26555.

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...discernible

It may be noted that their observations were performed with a chopping technique and on-line sky subtraction. Due to the limited chopping throw, it is possible that external regions of the galaxy, as well as faint objects nearby, are included in the sky measurement with a consequent underestimate of the source flux within the aperture. Because of this, and of the difficulty of centering faint objects within the aperture diaphragms, single-photometer measurements are expected to be slightly fainter than those acquired by panoramic detectors.

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...considered

Obviously such estimates, given in Table 3, do not usually coincide with the nightly averaged FWHM from standard stars listed in Table 2.

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...NED

This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

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