An Imaging Survey of Early‐Type Barred Galaxies

This paper presents the results of a high-resolution imaging survey, usingboth ground-based and Hubble Space Telescope images, of a complete sample ofnearby barred S0--Sa galaxies in the field, with a particular emphasis onidentifying and measuring central structures within the bars: secondary bars,inner disks, nuclear rings and spirals, and off-plane dust. A discussion of thefrequency and statistical properties of the various types of inner structureshas already been published. Here, we present the data for the individualgalaxies and measurements of their bars and inner structures. We set out themethods we use to find and measure these structures, and how we discriminatebetween them. In particular, we discuss some of the deficiencies of ellipsefitting of the isophotes, which by itself cannot always distinguish betweenbars, rings, spirals, and dust, and which can produce erroneous measurements ofbar sizes and orientations.