A subarcsecond resolution near-infrared study of Seyfert and "normal" galaxies. II. Morphology

We present a detailed study of the bar fraction in the CfA sample of Seyfer t galaxies and in a carefully selected control sample of nonactive galaxies to investigate the relation between the presence of bars and of nuclear ac tivity. To avoid the problems related to bar classification in the Third Re ference Catalogue (RC3), e.g., subjectivity, low resolution, and contaminat ion by dust, we have developed an objective bar classification method, whic h we conservatively apply to our new subarcsecond resolution near-infrared (NIR) imaging data set discussed in the first paper in this series We are a ble to use stringent criteria based on radial profiles of ellipticity and m ajor axis position angle to determine the presence of a bar and its axial r atio. Concentrating on noninteracting galaxies in our sample for which morp hological information can be obtained, we find that Seyfert hosts are barre d more often (79% +/- 7.5%) than the nonactive galaxies in our control samp le (59% +/- 9%); a result which is at the similar to 2.5 sigma significance level. The fraction of nonaxisymmetric hosts becomes even larger when inte racting galaxies are taken into account. We discuss the implications of thi s result for the fueling of central activity by large-scale bars. This pape r improves on previous work by means of imaging at higher spatial resolutio n and by the use of a set of stringent criteria for bar presence and confir ms that the use of NIR is superior to optical imaging for detection of bars in disk galaxies.