Intracluster Stars and the Chemical Enrichment of the Intracluster Medium

Abstract

We explore the contribution of intracluster stars (ICS) to the chemical enrichment history of the intracluster medium (ICM). In contrast to scenarios in which all the metals originate in cluster galaxies and are then transported into the ICM, intracluster stars enrich the ICM in situ, thereby contributing 100% of their supernovae ejecta directly into the ICM. Modeling the ICS as an ancient, single burst stellar population with a normal initial mass function, we generate ICM iron abundances in the range of the observed values of several tenths solar. Large observational and theoretical uncertainties preclude us from concluding that the intracluster stars are the primary contributor of metals to the ICM in general. However, for the two clusters in our sample, and one from the literature, for which all of the required observational constraints exist, we are able to reproduce between half and all of the ICM iron. Due to the ubiquity of intracluster stars in clusters and their direct connection with the ICM, we conclude that all models of the chemical enrichment history and energy budget of the ICM should account for the impact of the ICS.