Origin of the Stellar Disk in the Nucleus of the SB0 NGC 1023

Using archival Hubble Space Telescope imaging and ground-based integral-field spectroscopy, we investigated the structure and stellar populations of the nuclear stellar disk hosted in the interacting SB0 galaxy NGC 1023. The stars of the nuclear disk are remarkably younger and more metal-rich with respect to the host bulge. These findings support a scenario in which the nuclear disk is the end result of star formation in gas piled up in the galaxy center. The gas can be of either internal or external origin, from the main disk of NGC 1023 or from the nearby satellite NGC 1023A, respectively. The dissipationless formation from already formed stars through the migration and accretion of star clusters into the galactic center is rejected.