Enhanced abundances in spiral galaxies of the Pegasus i cluster

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 HII 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 HI deficiency. The galaxies in the Pegasus cluster, despite its lower density and velocity dispersion, also display gas loss due to interstellar-medium-intracluster-medium interaction, albeit to a lesser degree. Based on the abundances of three HI deficient spirals and two HI normal spirals, we observe a heavy element abundance offset of +0.13 ± 0.07 dex for the HI deficient galaxies. This abundance differential is consistent with the differential observed in Virgo for galaxies with a similar HI deficiency, and we observe a correlation between log (O/H) and the HI 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. © 2012 The American Astronomical Society. All rights reserved.