Flocculent and grand design spiral galaxies in groups - Time scales for the persistence of grand design spiral structures

Abstract

It has been found that the length, continuity, and symmetry of spiral arms in galaxies depend on the presence of a bar in the galactic center and on the presence of binary or group companions. Elmegreen and Elmegreen (1982) have shown that only 32% + or - 10% of the nonbarred galaxies outside of group or binary systems have grand design spirals, while 57% + or - 19% and 68% + or - 7% of nonbarred galaxies in binaries and groups, respectively, have such structure. The compilation of galaxy groups by Huchra and Geller (1982) is used in the present investigation to illustrate an additional correlation between spiral structure and galactic environment. Groups with the shortest crossing times or galaxy collision times have the largest proportions of grand design spirals in nonbarred galaxies. The results implies that grand design spirals may persist for a long time in galaxies.