Chemical Enrichment of the ICM

Therefore, the XpejXpe shown in Table 2 was calculated as (Mpe)pred/(Mgas)0f,s. The predicted Fe abundance in the ICM relative to the Sun is in agreement with the observations then and now (Xpe/(Xpe )0bs = 0.3 — 0.5 (Rothenflug Arnaud 1985 White 2000). Low values for [Mg/Fe] and [Si/Fe] were predicted due to the assumption that all the Fe, produced by Type la SNe, was soon or later ejected into the ICM, as shown in Table 2. With Salpeter IMF, Type la SNe contribute 50% of the total Fe. 

Abundance ratios and the Iron Mass to Light Ratio (IMLR) are good tests for the evolution of galaxies in clusters since they do not depend on the total cluster gas mass. The IMLR is defined as (Renzini et al. 1993)  

The main conclusions on the chemical enrichment of the ICM can be summarized as follows  

FIGURE 12. The predicted evolution of the thermal content of the ICM (upper panel) as a function of redshift. The different contributions from SNe of different type is indicated. In the lower panel is shown the evolution of the total Fe mass as a function of redshift. The assumed cosmological model is = 0.3, Q = 0.7 and h=0.70. 

Gratton, R. G., Carretta, E., Matteucci, F. Sneden, C., 2000, A A 358, 671 GREGGIO, L., 1996 Interplay between massive star formation, the ISM and galaxy evolution, IAP Meeting July 1995, Editions Frontieres, p.89 Greggio, L. Renzini, A., 1983, A A 118, 217 

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Good models for the chemical enrichment of the ICM should reproduce at the same time the [a/Fe] ratios inside galaxies and in the ICM. They should also reproduce the IMLR. 

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