THE BULLS-EYE EFFECT - ARE GALAXY WALLS OBSERVATIONALLY ENHANCED

We investigate a distortion in redshift space that causes galaxies to appear to lie in walls concentric about the observer, forming a rough bull's-eye pattern. We simulate what an observer would see in a thin s lice of redshift space, including a magnitude limit and constant slice angle. The result is an enhanced ring of galaxies encircling the obse rver at a distance roughly corresponding to the peak of the selection function. This ring is an artificial enhancement of weak features in r eal space. This may explain visually prominent features such as the Gr eat Wall and periodicity found in deep narrow fields.