Structural parameters of dwarf galaxies in the Coma Cluster:: On the origin of dS0 galaxies

In this paper we analyze the structural parameters of the dwarf galaxies in the Coma Cluster with -18 <= M-B <= -16 and classify them into two types; those with surface brightness profiles well fitted by a single Sersic law are called dwarf ellipticals (dEs), and those fitted with Sersic+exponential profiles are classified as dwarf lenticulars (dS0s). The comparison of the structural parameters of the dwarf galaxies in the Coma and Virgo Clusters shows that they are analogous. Photometrically, the dE and dS0 galaxies in Coma are equivalent, having similar colors and global scales. However, the scale of the innermost parts (bulges) of dS0 galaxies is similar to that of the bulges of late-type spiral galaxies. In contrast, dEs have larger scales than the bulges of bright galaxies. This may indicate that dS0 and dE galaxies have different origins. While dE galaxies can come from dwarf irregulars (dIs) or from processes similar to those that form bright E galaxies, the origin of dS0 galaxies could be harassed bright late-type spiral galaxies.