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 $-18 \le M_{B} \le -16$ and classify them in two types: those with surface brightness profiles well fitted by a single Sersic law were called dwarf ellipticals (dEs), and those fitted with Sersic-plus-exponential profiles were 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 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 similar processes as bright Es, the origin of dS0 galaxies can be harassed bright late-type spiral galaxies.Comment: 48 pages, 14 figure, 4 tables. Accepted for publication in A