ENRICHMENT AND HEATING OF THE INTRACLUSTER MEDIUM THROUGH GALACTIC WINDS

In previous papers we presented the results of simulations concerning the dynamic and X-ray evolution of the interstellar medium in elliptical galaxies. We found that all model galaxies developed Type II supernova-driven winds at early epochs and that low-luminosity ellipticals (L(B) less-than-or-similar-to 10(9.5)) maintained galactic winds for most of their lifetime. Since the galaxy population of rich regular clusters is dominated by elliptical and SO galaxies, we examine in this paper what effect these galactic winds have on the heavy element abundance and energetics of the intracluster medium. Substantial injection of highly enriched gas occurs within 3 x 10(8) yr after galaxy formation through galactic winds. The resulting iron abundance of the intracluster medium through galactic winds varies considerably with the assumed stellar initial mass function, Type I supernova rate, and the primordial mass fraction of the cluster gas. The combined mechanical luminosity of the winds from the galaxies in a cluster can greatly exceed the present optical luminosity of a cluster. Any residual gas remaining in a cluster after the cessation of galaxy formation can be heated to temperatures exceeding that produced by gravitational heating alone. Assuming the distribution of galaxy luminosities in a cluster can be described by a Schechter luminosity function, our calculations show that the observed iron abundance, oxygen-to-iron mass ratio, and gas temperature in clusters can all be simultaneously reproduced only if the first generation of stars formed with a relatively flat initial mass function. Results from calculations using a Salpeter initial mass function do not agree with observations.