The nuclear cusp slopes of dwarf elliptical galaxies

We derive the light profiles for a sample of 25 dwarf elliptical galaxies o bserved by us with Hubble Space Telescope's Wide Field and Planetary Camera 2 in F555W and F814W. These profiles are fitted with Nuker, R-1/4, exponen tial, and Sersic laws and are also used to derive the nuclear cusp slopes g amma. We discuss the correlation of nuclear cusp slope with galactic lumino sity, the presence of a nucleus, and the type of light profile. The results are compared with those found in the literature for elliptical galaxies an d the bulges of spiral galaxies. We find that, as a class, the nuclear regi ons of dwarf ellipticals are very similar to those of the exponential bulge s of spiral galaxies and have nuclear cusp slopes shallower than those of b ulges with the same luminosity that were well fitted by a de Vaucouleurs R- 1/4 profile. For the 14 nucleated galaxies in our sample, this conclusion i s less certain than for the 11 nonnucleated objects, since it relies on an extrapolation of galaxy light under the nucleus. In terms of their light pr ofiles and nuclear properties, most spheroidal stellar systems can be broad ly divided into two subclasses : the exponential shallow cusp objects and t he R-1/4 steep cusp objects. Membership of a class does not appear to corre late with the presence of a massive stellar disk.