Published online by Cambridge University Press: 10 November 2010
We are carrying out a deep study of the CfA Seyfert sample of Seyfert galaxies in broad-band and narrow-band Hα. Our aim is to perform a complete analysis of the morphological properties of the galaxies hosting the Seyfert nuclei. We will also study the location and number of circumnuclear star-forming regions, and the incidence of interactions and galaxy-wide starbusts, emphasizing the similarities and differences between the type 1 and type 2 objects.
Previous studies of active galaxies have been mainly concerned with the properties of the active nucleus. In fact, the many varieties of AGN recognised today were separated according to their nuclear properties. Yet the importance of the host galaxy in the understanding of the nuclear activity has been pointed out by several authors. For instance, some authors suggest that the host galaxies of Seyfert nuclei are substantially more luminous than similar field galaxies in the far infrared (Rodríguez Espinosa et al. 1987; Edelson et al. 1987; Rieke 1992), implying a connection between galaxy-wide star formation and Seyfert activity. Other authors find differences between the stellar formation rates in the host galaxies of Seyfert 1 and Seyfert 2 (Heckman et al. 1989).
It has also been known for some time that Seyfert 1's and 2's tend to be hosted by spiral galaxies of different morphological types, Seyfert 2's ocurring more often in latetype spirals than Seyfert 1's.