Stellar Populations of Spectroscopically Decomposed Bulge-Disk for S0 Galaxies from the CALIFA survey

TL;DR

This study analyzes the stellar populations of bulges and disks in 34 S0 galaxies using integral field spectroscopy, revealing how mass and environment influence their evolution and star formation histories.

Contribution

It provides a detailed, spatially resolved comparison of bulge and disk stellar populations in S0 galaxies, highlighting the roles of mass and environment in galaxy evolution.

Findings

Bulges and disks show different age-metallicity relations.

High-mass S0 bulges are more metal-rich than disks.

Bulge and disk ages increase with local density.

Abstract

We investigate the stellar population properties of bulges and disks separately for 34 S0s using integral field spectroscopy from the Calar Alto Legacy Integral Field Area survey. The spatially resolved stellar age and metallicity of bulge and disk components have been simultaneously estimated using the penalized pixel fitting method with photometrically defined weights for the two components. We find a tight correlation between age and metallicity for bulges, while the relation for disks has a larger scatter than that of bulges. This implies that the star formation histories of the disks are more complicated than those of the bulges. Bulges of the high-mass S0s are mostly comparable in metallicity, while bulges appear to be systematically more metal-rich than disks for the low-mass S0s. The ages of bulges and disks in the high-mass S0s appear to increase with local density. The bulge ages of the low-mass S0s also increases with local density, but such a trend is not clear in the disk ages of low-mass S0s. In addition, the age difference between bulge and disk components (delta Age) tends to increase with local density, both for the high-mass and low-mass S0s. The high-mass S0s have systematically higher delta Age than the low-mass S0s at given local density. Our results indicate that the stellar mass significantly influences the evolution of S0 galaxies, but the environment also plays an important role in determining the evolution of bulges and disks at given stellar mass.