The abundance properties of nearby late-type galaxies. II. The relation between abundance distributions and surface brightness profiles

Abstract

The relations between oxygen abundance and disk surface brightness (OH-SB relation) in the infrared W1 band are examined for nearby late-type galaxies. The oxygen abundances were presented in Paper I. The photometric characteristics of the disks are inferred here using photometric maps from the literature through bulge-disk decomposition. We find evidence that the OH-SB relation is not unique but depends on the galactocentric distance r (taken as a fraction of the optical radius R25) and on the properties of a galaxy: the disk scale length h and the morphological T-type. We suggest a general, four-dimensional OH-SB relation with the values r, h, and T as parameters. The parametric OH-SB relation reproduces the observed data better than a simple, one-parameter relation; the deviations resulting when using our parametric relation are smaller by a factor of ~1.4 than that of the simple relation. The influence of the parameters on the OH-SB relation varies with galactocentric distance. The influence of the T-type on the OH-SB relation is negligible at the centers of galaxies and increases with galactocentric distance. In contrast, the influence of the disk scale length on the OH-SB relation is at a maximum at the centers of galaxies and decreases with galactocentric distance, disappearing at the optical edges of galaxies. Two-dimensional relations can be used to reproduce the observed data at the optical edges of the disks and at the centers of the disks. The disk scale length should be used as a second parameter in the OH-SB relation at the center of the disk while the morphological T-type should be used as a second parameter in the relation at optical edge of the disk. The relations between oxygen abundance and disk surface brightness in the optical B and infrared K bands at the center of the disk and at optical edge of the disk are also considered. The general properties of the abundance-surface brightness relations are similar for the three considered bands B, K, and W1.