Optical multiband surface photometry of a sample of Seyfert galaxies: III. Global, isophotal, and bar parameters†

摘要

This paper is third in a series, studying the optical properties of a sample of Seyfert galaxies. Here we present a homoge neous set of global (ellipticity, position angle, inclination, and total magnitude) and isophotal (semi-major axis and colour indices at 24V mag arcsec–2) parameters of the galaxy sample. We find the following median corrected isophotal colour indices: (B – I_C)(0)₂₄ = 1.9 mag arcsec–2 and (V – I_C)(0)₂₄ = 1.1 mag arcsec–2. A set of bar parameters (ellipticity, position angle, semi-major axis corresponding to the ellipticity maximum in the bar region, and length) are also reported; deprojection has been applied to the bar ellipticity, length, and relative length in terms of galaxy isophotal semi-major axis. Regarding bar length estimation, we use a method, based on the relation between the behaviour of the profiles and orbit analysis. The so estimated bar length tightly correlates with the semi-major axis, corresponding to the ellipticity maximum with a median ratio of the former to the latter of 1.22. The median of the deprojected bar ellipticity, length, and relative length are 0.39, 5.44 kpc, and 0.44, respectively. There is a correlation between the deprojected bar length and the corrected isophotal semi-major axis at 24V mag arcsec–2. Three of the 17 large-scale bars appear strong, based on the deprojected bar ellipticity as a first-order approximation of bar strength. The deprojected relative bar length does not appear to correlate with the bar ellipticity (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)