NUCLEAR PROPERTIES OF KINEMATICALLY DISTINCT CORES

We present WFPC2 F450W, F555W, and F814W photometry for three early-ty pe galaxies with kinematically distinct cores (KDCs), namely NGC 2434, NGC 7192, and IC 4889. For these three objects we present the B, V, a nd I nuclear surface brightness, isophotal, B-V and V-I profiles and d erive the deprojected luminosity densities. The three KDCs have nuclea r cusp slopes [gamma(v)] in agreement with the [gamma(v)] versus absol ute magnitude (M-v) relation defined by kinematically normal galaxies and by other KDCs. NGC 7192 contains an unresolved blue nuclear spike of V similar or equal to 22.2, B-V similar or equal to 0, and V-I simi lar or equal to 0.7. We use these new data, and the WFPC2 photometry f or 15 KDCs presented in Carollo et al., to investigate several open qu estions related to the nuclear properties of this class of galaxies, W e find the following : 1. If there is a direct effect of environment o n the nuclear properties of KDCs, this is similar to that acting on ki nematically normal galaxies. Dynamically hot systems preferentially ha ve low nuclear densities and shallow cusps when in clusters and high n uclear densities and steep cusps when in the field. The highest nuclea r densities are reached in the field. 2. Within the limits imposed by the angular resolution of WFPC2 data and by the presence of nuclear du st, KDCs have symmetric nuclei. This result is independent of environm ent, form of the nuclear light profiles, nuclear morphology, and prese nce of an unresolved, likely nonthermal, central source. 3. The known Mg-2 index-enhanced KDCs might not be all nuclear disks embedded in an isotropic stellar bodies. Three galaxies, namely NGC 2434, NGC 7192, a nd NGC 7626, do not show any photometric signature for a nuclear disk associated with their Mg-2-rich KDCs. The Mg-2-rich KDCs may arise fro m a large variety of morphological (and dynamical) structures, possibl y indicating a variety of star formation and dynamical histories. 4. T he ''delta-delta'' correlation between the residuals of the [gamma(v)] versus M-v relation, and Mg-2 versus M-v relation, is approximately a t the 3 sigma level, which implies a residual dependence of the cusp s lope [gamma(v)] on the Mg-2 line strength: the higher the Mg enrichmen t, the shallower the nuclear cusp slope. 5. The Mg-2-enhanced KDCs do not occupy any special location in the correlation between [gamma(v)] and Mg-2 (correlation that worsens significantly if for these KDCs one considers the Mg-2 value extrapolated from the outer galactic regions ). They also do not occupy any special location in the ''delta-delta'' correlation above. Therefore, our data suggest that the processes tha t made the KDCs in the host galaxies (on scales of approximate to 1 kp c) also rebuilt their central structures (i.e., the nuclear cusps on s cales less than or similar to 100 pc). Finally, our work adds further support to the previous findings (Forbes et al.; Carollo et al.) that KDCs show little or no evidence for any photometric difference compare d to other early-type systems of similar luminosity.