N.D. Kylafis 1, E. Xilouris 2, & J. Papamastorakis 1
1 University of Crete, Physics Departement, P.O. Box 2208, 710 03 Heraklion Crete, Greece
2 Univesity of Athens
A detailed study of the spatial distribution of stars and dust in spiral
galaxies is presented. We have taken optical surface photometry of seven,
nearby, edge-on spiral galaxies and have compared it with surface photometry
calculated from a realistic model of spiral galaxies with full radiation
transfer, taking into account both absorption and scattering by dust. Two
of these galaxies have also been observed and modeled in the near infrared.
We find it impressive that all seven galaxies exhibit similar characteristics.
These are: 1) Despite their prominent dust lanes, the galaxies would be
completely transparent (optical depth in the B band less than unity) if they
were seen face-on. 2) The extinction as a fuction of wavelength in all of
them is identical to that of our Galaxy. 3) The scale length of the dust in
the disk is larger than the scale length of the stars there and the dust
extends beyond the optical disk. 4) The gas to dust ratio is comparable to
that of our Galaxy for all of them. 5) The mean face-on central surface
brightness in the B band is approximately 23 mag arcsec-2.