Young Stellar Nuclei in the Lenticular Galaxies. I. NGC 1023 and NGC 7332

Abstract

As a result of bidimensional spectroscopy of the central parts of two nearby lenticular galaxies, NGC 1023 and NGC 7332, undertaken with the Multi-Pupil Field Spectrograph of the 6 m telescope of the Special Astrophysical Observatory, their chemically decoupled stellar nuclei are found to be substantially younger than the surrounding bulges: the mean age of the nuclear stellar populations is 7 Gyr in NGC 1023 and 2.5+/-0.5 Gyr in NGC 7332. The morphological analysis undertaken by Seifert & Scorza for NGC 7332 and by us for NGC 1023 has revealed a existence of separate circumnuclear stellar disks with the radius of 80 pc in NGC 1023 and of 400 pc in NGC 7332; probably, the intermediate-age stellar populations are related to these structures.