Brief history of metal accumulation in the intracluster medium

Abstract

We use models of the rates of Type la supernovae (SNe Ia) and core-collapsed supernovae, built in such a way that both are consistent with recent observational constraints at z ≲ 1.6 and can reproduce the measured cosmic star formation rate, to recover the history of metal accumulation in the intracluster medium. We show that these SN rates, in unit of SN number per comoving volume and rest-frame year, provide on average a total amount of iron that is marginally consistent with the value measured in galaxy clusters in the redshift range 0-1, and a relative evolution with redshift that is in agreement with the observational constraints up to z ≈ 1.2. Moreover, we verify that the predicted metals-to-iron ratios reproduce the measurements obtained in nearby clusters through X-ray analysis, implying that (1) about half of the iron mass and ≲75 per cent of the nickel mass observed locally are produced by SN Ia ejecta, (2) the SN Ia contribution to the metal budget decreases steeply with redshift and by z ≈ 1 is already less than half of the local amount, and (3) a transition in the abundance ratios relative to iron is present between redshifts ∼0.5 and 1.4, with core-collapsed SN products becoming dominant at higher redshifts. © 2005 RAS.