Signatures of recent star formation in ring S0 galaxies

TL;DR

This study investigates recent star formation in ring structures of S0 galaxies using UV and optical data, revealing rejuvenation events and their potential triggers.

Contribution

It provides a quantitative analysis of the age, mass, and star formation activity in UV-bright rings of S0 galaxies, highlighting their significance in galaxy evolution.

Findings

UV rings contain a few percent of galaxy mass

UV luminosity of rings can reach 70% of galaxy luminosity

Galaxies are located in the red sequence and green valley

Abstract

We present a study of the stellar populations of ring and/or arm-like structures in a sample of S0 galaxies using GALEX far- and near-ultraviolet imaging and SDSS optical data. Such structures are prominent in the UV and reveal recent star formation. We quantitatively characterize these rejuvenation events, estimating the average age and stellar mass of the ring structures, as well as of the entire galaxy. The mass fraction of the UV-bright rings is a few percent of the total galaxy mass, although the UV ring luminosity reaches 70% of the galaxy luminosity. The integrated colors of these S0s locates them in the red sequence (NGC 2962) and in the so-called green valley. We suggest that the star formation episodes may be induced by different triggering mechanisms, such as the inner secular evolution driven by bars, and interaction episodes.