Enhanced Abundances in Spiral Galaxies of the Pegasus I Cluster

TL;DR

This study investigates how the cluster environment influences the chemical evolution of spiral galaxies in the Pegasus I cluster, revealing that gas loss due to interactions enhances heavy element abundances similarly to what is observed in the Virgo cluster.

Contribution

It provides new evidence that environmental effects in galaxy clusters lead to increased metallicity in spiral galaxies, even in lower-density clusters like Pegasus I.

Findings

H I deficient galaxies show +0.13 dex higher metallicity.

Environmental mechanisms cause similar metallicity enhancements in Pegasus I and Virgo.

A correlation exists between metallicity and H I deficiency across both clusters.

Abstract

We study the influence of cluster environment on the chemical evolution of spiral galaxies in the Pegasus I cluster. We determine the gas-phase heavy element abundances of six galaxies in Pegasus derived from H II region spectra obtained from integral-field spectroscopy. These abundances are analyzed in the context of Virgo, whose spirals are known to show increasing interstellar metallicity as a function of H I deficiency. The galaxies in the Pegasus cluster, despite its lower density and velocity dispersion, also display gas loss due to ISM-ICM interaction, albeit to a lesser degree. Based on the abundances of 3 H I deficient spirals and 2 H I normal spirals, we observe a heavy element abundance offset of +0.13\pm0.07 dex for the H I deficient galaxies. This abundance differential is consistent with the differential observed in Virgo for galaxies with a similar H I deficiency, and we observe a correlation between log(O/H) and the H I deficiency parameter DEF for the two clusters analyzed together. Our results suggest that similar environmental mechanisms are driving the heavy element enhancement in both clusters.