Hubble Space Telescope Detection of Spiral Structure in Two Coma Cluster Dwarf Galaxies

Abstract

We report the discovery of spiral-like structure in Hubble Space Telescope images of two dwarf galaxies (GMP 3292 and GMP 3629) belonging to the Coma Cluster. GMP 3629 is the faintest such galaxy detected in a cluster environment, and it is the first such galaxy observed in the dense Coma Cluster. The large bulge and the faintness of the broad spiral-like pattern in GMP 3629 suggest that its disk may have been largely depleted. We may therefore have found an example of the ``missing link'' in theories of galaxy evolution that have predicted that dwarf spiral galaxies, particularly in clusters, evolve into dwarf elliptical galaxies.

Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.