Metallicity Gradients in X‐Ray Clusters of Galaxies

Abstract

We present the projected metallicity profiles for a sample of 17 rich galaxy clusters observed by BeppoSAX. We find that the 8 non-cooling flow clusters have flat metallicity profiles. On the contrary, a strong enhancement in the abundance is found in the central regions of the cooling flow clusters. All the non-cooling flow clusters present evidence of recent merger activity suggesting that the merger events redistributes efficiently the metal content of the intracluster medium. For the cooling flow clusters with better statistics and available optical data (A85, A496, A2029 and Perseus) we have tested whether the observed abundance excess is due to metals ejected from the galaxies located in the cluster core. We find that at a resolution > 100 kpc the observed projected abundance excess profiles are consistent with originating from a deprojected metal excess distribution tracing the optical light distribution. In the one case (i.e. Perseus) with higher resolution (~ 50 kpc), we find that the observed metal abundance excess distribution is broader than the predicted one. Such a difference can be reconciled if we assume that the metals have drifted away from their parent ejecting galaxies by a few tens of kpc, or, alternatively, if we assume that the cluster light profile has become significantly more centrally peaked because of the formation process of the central dominant cluster galaxy since the last major merger occurred.