Some of the classical seyferts are observed to be prototypical ovals, e.g. NGC 1068 and 4151 (e.g., Bosma 1981; Kormendy 1982; Scoville et al. 1988). Such a non-axisymmetric potential corresponding to an oval disk can produce inward flow of gas and induce mild activity. To test the efficiency of this process, we study a collision between a face-on spiral with a high gaseous content and an equally massive compact elliptical, under marginally bound conditions, as such encounters are most frequent.

We model the spiral galaxy by an exponential model disk (of radius R) with a (static) thickness and scale length α = 4/R and a spherical polytropic bulge (n=0,3,4, equally weighted combination) containing 1/3 of the mass (cf. Chatterjee 1990); about 20% of the mass of the disk contains gas particles. The elliptical is modeled identically as the bulge. The gravitational potential is softened with softening constants of ∊ = r∘/5, r∘/3, and 0.8r∘, for the bulge of the spiral as well as the elliptical, stellar and gaseous components of the disk, respectively. Here r∘ is the radius containing 75% of the total mass of the galaxy in question, while the mutual gravitational interaction is softened with a softening constant of r∘/4.