Spectral study of starforming rings in S0 galaxies of Dorado group -- NGC 1533 and NGC 1543

TL;DR

This study provides a detailed spectroscopic analysis of star-forming rings in two S0 galaxies in the Dorado group, revealing external gas origins and stellar population characteristics.

Contribution

It offers new insights into the kinematics, gas origin, and stellar populations of star-forming rings in barred lenticular galaxies.

Findings

Asymmetric decoupled stellar and gas kinematics suggest external gas acquisition.

Star formation rates in the rings are derived from ultraviolet fluxes.

Inner stellar populations are predominantly old, with recent rejuvenation in NGC 1543's nucleus.

Abstract

We have fulfilled a detailed long-slit spectroscopic analysis for two SB0 galaxies -- NGC 1533 and NGC 1543, -- belonging to the Dorado group. Our spectral data reveal asymmetric decoupled kinematics of the stars and ionised gas in these barred lenticular galaxies that give evidences for external origin of the gas in the rings. We have calculated the star formation rates in the rings by using the ultraviolet fluxes of the rings corrected for the foreground and intrinsic absorption; and we have estimated parameters of the stellar populations in the inner parts of the galaxies confirming that they are old -- except the nucleus of NGC 1543, which demonstrates signatures of re-juvenation less than 5 Gyr ago.