Stirring Up the Pot: Can Cooling Flows In Galaxy Clusters Be Quenched By
  Gas Sloshing?
  X-ray observations of clusters of galaxies reveal the presence of edges in
surface brightness and temperature, known as "cold fronts". In relaxed clusters
with cool cores, these commonly observed edges have been interpreted as
evidence for the "sloshing" of the core gas in the cluster's gravitational
potential. Such sloshing may provide a source of heat to the cluster core by
mixing hot gas from the cluster outskirts with the cool core gas. Using
high-resolution $N$-body/Eulerian hydrodynamics simulations, we model gas
sloshing in galaxy clusters initiated by mergers with subclusters. The
simulations include merger scenarios with gas-filled and gasless subclusters.
The effect of changing the viscosity of the intracluster medium is also
explored. We find that sloshing can facilitate heat inflow to the cluster core,
provided that there is a strong enough disturbance. In adiabatic simulations,
we find that sloshing can raise the entropy floor of the cluster core by nearly
an order of magnitude in the strongest cases. If the ICM is viscous, the mixing
of gases with different entropies is decreased and consequently the heat flux
to the core is diminished. In simulations where radiative cooling is included,
we find that though eventually a cooling flow develops, sloshing can prevent
the significant buildup of cool gas in the core for times on the order of a Gyr
for small disturbances and a few Gyr for large ones. If repeated encounters
with merging subclusters sustain the sloshing of the central core gas as is
observed, this process can provide a relatively steady source of heat to the
core, which can help to prevent a significant cooling flow.
