ABSTRACT

The idea that Seyfert nuclear activity might be fueled by material inflow induced by a perturbing companion has been fashionable for over a decade. However, the recent literature on the prevalence of Seyfert galaxy companions, is confusing and somewhat contradictory. To clarify this we have constructed a statistical profile of Seyfert galaxy companions in the CfA ZCAT. We use a random sampling technique to estimate the statistical significance of the observed excess of Seyfert companions relative to the rate of pairing found in non-active galaxies. We find the excess of close pairs for Seyfert galaxies to be highly significant.

RESULTS

More than a decade ago, the morphological similarities between patterns seen in Seyfert galaxies and those produced by gravitational forcing led to the suggestion that Seyfert activity might be fueled by material inflow induced by either a central bar or a perturbing companion (Simkin, Su, and Schwarz 1980). The recent literature on the prevalence of Seyfert galaxy companions, however, is somewhat confusing and, at initial glance, contradictory (cf. the extensive review in Osterbrock 1991). Most authors have attributed their disparate conclusions to observational selection effects, (op. cit.). The problems arise because to obtain a valid statistical profile of the non-AGN “control” galaxies requires either an enormous observational effort or a series of ad hoc assumptions which differ with each study.

An alternative approach to this statistical problem is to draw the Seyfert galaxy sample from a larger catalog of galaxies all subject to the same measurement errors and selection effects. With this approach, the non-Seyfert galaxies provide the statistical profile necessary for interpretation.