Analysis of seven face-on spiral galaxies^*

¹ now at: Università di Trieste, Dip. di Astronomia, S.I.S.S.A.e Via Beirut 2-4 34013 Trieste, Italy
² Istituto di Astrofisica Spaziale C.N.R.-I.A.S. Via Enrico Fermi 23, 00044 Frascati (RM), Italy

Received: 16 July 1996
Accepted: 16 November 1996

Abstract

We continue in this work the study of nearby spiral galaxies started with NGC 628 (Natali 1992, hereafter Paper I). A sample of seven face-on spiral galaxies has been selected to obtain images in the U, B, V, R, I bands using a CCD detector at the 90 cm Schmidt telescope at Campo Imperatore Observatory. Surface photometry using a dedicated software is used to derive both the surface brightness radial profiles in each band and the colour indexes. The radial disk scalelengths obtained from the radial profiles show a trend with wavelength which seems to highlight a huge presence of dust in the inner disk zone. For two galaxies of the sample the presence of dust is confirmed by the radial trend of colour indexes. The presence of galactic infall already detected for NGC 628, is confirmed, from the bluish , also for NGC 3184.