The Signatures of Galactic Disk Evolution in Vertical Colour Profiles of Edge-On Galaxies
Galactic disks are heated by some gravitational scattering process. The velocity dispersion and scale height increases with the age of the stellar populations as can be observed directly in the solar neighbourhood. This evolutionary effect can also be derived from the vertical structure of spiral galaxies seen edge-on. We use a physical model of a selfgravitating disk composed of isothermal subpopulations with increasing age and velocity dispersion and an exponential dust distribution (Just et al. 1995). The emissivity of the stars is computed from the luminosities in the different bands of single age populations which are computed with the method of photometric evolutionary synthesis (Einsel et al. 1995).