Author(s): E M Xilouris, Y I Byun, N D Kylafis, E V Paleologou, J Papamastorakis
The opacity of spiral galaxies is examined by modelling the dust and stellar content of individual galaxies. The three dimensional model that we use assumes exponential distributions for the dust and the stars in the disk, while the R 1 / 4 law is used to describe the bulge. In this model, both absorption and scattering by the dust are taken into account. The model is applied to five late-type spiral galaxies (NGC 4013, IC 2531, UGC 1082, NGC 5529 and NGC 5907) using their optical (and near infrared for IC 2531) surface photometry. For these galaxies we have determined the scalelengths and scaleheights of the stars and the dust in the disk, the bulge characteristics, the inclination angle and the face-on optical depth. Computation of the dust masses, as well as the extinction as a function of the wavelength, are also reported.