Evolution with redshift of the ICM abundances

We predict the behaviour of the abundances of alpha-elements and iron in th e intracluster medium (ICM) as a function of redshift in poor and rich clus ters. In order to do that we calculate the detailed chemical evolution of e lliptical galaxies by means of one-zone and multi-zone models and then we i ntegrate the contributions to the total gas and single elements by elliptic als over the cluster mass function at any given cosmic time which is then t ransformed into redshift according to the considered cosmological model. In the case of the multi-zone model for ellipticals the more external regio ns evolve much faster than the internal ones which maintain a very low leve l of star formation almost until the present time. In other words, the oute rmost regions develop a galactic wind, after which the region evolves passi vely, at much earlier times than the innermost regions as opposed to the cl assic one-zone model where the galactic wind develops at early times over t he whole galaxy. We refer to the one-zone model as to burst model and to th e multi-zone model as to continuous model. We find that in the case of the burst model the ICM abundances should be quite constant starting from high redshifts (z > 2) up to now, whereas in the continuous model the ICM abunda nces should increase up to z similar to 1 and are almost constant from z si milar to 1 up to z = 0. Particular attention is devoted to the predictions of the [alpha/Fe](ICM) r atio in the ICM: for the burst model we predict [alpha/Fe](ICM) > 0 over th e whole range of redshifts and in particular at z = 0, whereas in the case of the continuous model we predict a decreasing [alpha/Fe](ICM) ratio with decreasing z and [alpha/Fe](ICM) less than or equal to 0 at z = 0. In parti cular, we predict [O/Fe](ICM)(z = 0) less than or equal to +0.35 dex and [S i/Fe](ICM)(z = 0) less than or equal to +0.15 dex for the burst models and [O/Fe]ICM(z = 0) less than or equal to -0.05 dex and [Si/Fe](ICM)(z = 0) le ss than or equal to +0.13 dex for the continuous models, the precise values depending on the assumed cosmology. Finally, we discuss the influence of d ifferent cosmologies on the results.