Understanding the transformation of spirals to lenticulars

TL;DR

This study investigates how spiral galaxies transform into lenticulars by analyzing their star-formation histories, revealing that star formation ceases in the disc before a final burst occurs in the bulge due to inward gas funneling.

Contribution

It provides spectroscopic evidence of the sequential quenching of star formation in discs followed by central activity in S0 galaxies, elucidating the transformation process.

Findings

Star formation in discs is quenched before bulge activity.

Recent star formation occurs in bulges fueled by residual disc gas.

Gas inflow triggers final star formation episode in bulges.

Abstract

By studying the individual star-formation histories of the bulges and discs of lenticular (S0) galaxies, it is possible to build up a sequence of events that leads to the cessation of star formation and the consequent transformation from the progenitor spiral. In order to separate the bulge and disc stellar populations, we spectroscopically decomposed long-slit spectra of Virgo Cluster S0s into bulge and disc components. Analysis of the decomposed spectra shows that the most recent star formation activity in these galaxies occurred within the bulge regions, having been fuelled by residual gas from the disc. These results point towards a scenario where the star formation in the discs of spiral galaxies are quenched, followed by a final episode of star formation in the central regions from the gas that has been funnelled inwards through the disc.