Formation of S0 galaxies through mergers: Explaining angular momentum and concentration change from spirals to S0s

TL;DR

This paper investigates whether major galaxy mergers can transform spiral galaxies into S0 galaxies by analyzing simulation data, providing an alternative to fading scenarios and explaining observed differences in angular momentum and concentration.

Contribution

It demonstrates that major mergers can account for the observed properties of S0 galaxies, offering a new explanation for spiral to S0 evolution.

Findings

Major mergers can reproduce the angular momentum and concentration of S0s.

The change in stellar angular momentum and concentration explains observed differences.

Major mergers are a feasible pathway for spiral to S0 galaxy transformation.

Abstract

The CALIFA team has recently found that the stellar angular momentum and concentration of late-type spiral galaxies are incompatible with those of lenticular galaxies (S0s), concluding that fading alone cannot satisfactorily explain the evolution from spirals into S0s. Here we explore whether major mergers can provide an alternative way to transform spirals into S0s by analysing the spiral-spiral major mergers from the GalMer database that lead to realistic, relaxed S0-like galaxies. We find that the change in stellar angular momentum and concentration can explain the differences in the $\lambda_\mathrm{Re}$--$R_{90}/R_{50}$ plane found by the CALIFA team. Major mergers thus offer a feasible explanation for the transformation of spirals into S0s.