The evolution of the interstellar medium in elliptical galaxies. I - The early wind phase

The evolving mass loss rates from type I and II SNe, stellar winds, and PN and the associated evolution of the mass-averaged temperature of the stellar ejecta are calculated. At early times, the mass-averaged temperature of the ejecta is found to be much greater than the central escape temperature from even very luminous elliptical galaxies due to the high frequency of type II SNe. The amount of oxygen and iron that can be injected into the intracluster medium from type II SN-driven winds in elliptical galaxies is calculated and the results are compared with observations. The gas ejected during this early wind phase is very hot and can heat the cluster gas to temperatures greater than that produced by gravitational heating alone. Two numerical simulations concerning the evolution of the ISM in an elliptical galaxy model with L(B) = 10 to the 11th solar are presented which confirm the existence of an early type II SN-driven wind phase and reproduce the observed X-ray properties of bright elliptical galaxies in the present epoch.