The optical and near-infrared distribution of light in the edge-on galaxy IC 2531

Optical and near-IR imaging of the edge-on galaxy IC 2531 is presented, and an attempt is made to derive the true distributions of stars and dust in this galaxy. The results suggest that the z dependence of the light distribution is better fitted by an exponential than by the isothermal sech-squared distribution. The dynamical implication of such a distribution is that the vertical velocity dispersion near the galactic plane should increase with z. A simple model for the light and dust distribution in IC 2531 employing three exponential components is constructed: an old disk, a young disk, and dust. Vertical scale heights of h(zd) = h(z)/4 and h(zy) = h(z)/8 and an absorption equivalent to about half of that in the Galaxy are found to produce the best fits.