  Simulations of galaxy clusters have a difficult time reproducing the radial
gas-property gradients and red central galaxies observed to exist in the cores
of galaxy clusters. Thermal conduction has been suggested as a mechanism that
can help bring simulations of cluster cores into better alignment with
observations by stabilizing the feedback processes that regulate gas cooling,
but this idea has not yet been well tested with cosmological numerical
simulations. Here we present cosmological simulations of ten galaxy clusters
performed with five different levels of isotropic Spitzer conduction, which
alters both the cores and outskirts of clusters, but not dramatically. In the
cores, conduction flattens central temperature gradients, making them nearly
isothermal and slightly lowering the central density but failing to prevent a
cooling catastrophe there. Conduction has little effect on temperature
gradients outside of cluster cores because outward conductive heat flow tends
to inflate the outer parts of the intracluster medium (ICM) instead of raising
its temperature. In general, conduction tends reduce temperature inhomogeneity
in the ICM, but our simulations indicate that those homogenizing effects would
be extremely difficult to observe in ~5 keV clusters. Outside the virial
radius, our conduction implementation lowers the gas densities and temperatures
because it reduces the Mach numbers of accretion shocks. We conclude that
despite the numerous small ways in which conduction alters the structure of
galaxy clusters, none of these effects are significant enough to make the
efficiency of conduction easily measurable unless its effects are more
pronounced in clusters hotter than those we have simulated.
