Young Nuclei in Dwarf Elliptical Galaxies

Abstract

We report discovery of young embedded structures in three diffuse elliptical galaxies (dE) in the Virgo cluster: IC 783, IC 3468, and IC 3509. We performed 3D spectroscopic observations of these galaxies using the MPFS spectrograph at the Russian 6-m telescope, and obtained spatially resolved distributions of kinematical and stellar population parameters by fitting high-resolution PEGASE.HR synthetic single stellar populations (SSP) in the pixel space. In all three galaxies, the luminosity weighted age of the nuclei, about 4 Gyr, is considerably younger than population in the outer regions of the galaxies. We discuss two possibilities to acquire the observed structures -- dissipative merger event and different ram pressure stripping efficiency during two consequent crossings of the Virgo cluster centre.

accepted to "Astronomy Letters". Version for astro-ph with colour figures. 14 pages, 3 figures, 2 tables