Multicolor optical imaging of infrared-warm Seyfert galaxies. III. Surface photometry: Light profile decomposition

This paper is the third in a series studying the optical properties of a sample of mid-infrared warm Seyfert galaxies and a control sample of mid-infrared cold galaxies. This paper is devoted to the analysis of the radial light distributions characterizing the galaxies outside their central 2 kpc. The light profiles are decomposed in inner and outer components using two generalized exponentials. Each component is characterized by a profile shape, a central surface brightness, and a scale length. We find that the warm Seyfert 1 galaxies tend to he in earlier-type hosts with more centrally concentrated light profiles as compared with the warm Seyfert 2 galaxies: the Seyfert 1 and 2 bulges have similar shapes, but the former are characterized by larger central surface brightness and smaller scale length. The cold galaxies are disk-dominated systems with complex morphologies. All these differences are confirmed at statistical significance levels better than 95%. The three parameters characterizing the bulge component correlate with each other for all samples within a limited range of bulge luminosities. The disk structural parameters span similar ranges (with large scatter) for both warm and cold samples. The parametrization of light profiles, as described in this paper, shows that the warm Seyfert 1, Seyfert 2, and cold samples occupy different loci in parameter space, clearly suggesting intrinsic differences between their host galaxy populations. This conclusion will be reinforced in two forthcoming papers, in which we will explore the color distributions and the interaction characteristics of our samples.