Heat conduction in cooling flows

Abstract

It has been suggested that electron conduction may significantly reduce the accretion rate (and star forma-tion rate) for cooling flows in clusters of galaxies. A numerical hydrodynamics code was used to investigate the time behavior of cooling flows with conduction. The usual conduction coefficient is modified by an effi-ciency factor, n, to realize the effects of tangled magnetic field lines. Two classes of models are considered, one where fi is independent of position and time, and one where inflow stretches the field lines and changes ju. In both cases, there is only a narrow range of initial conditions for ju in which the cluster accretion rate is reduced while a significant temperature gradient occurs. In the first case, no steady state solution exists in which both conditions are met. In the second case, steady state solutions occur in which both conditions are met, but only for a narrow range of initial values when n = 10 -2 .