The growth of the galaxy cluster Abell 85: mergers, shocks, stripping
  and seeding of clumping
  We present the results of deep Chandra, XMM-Newton and Suzaku observations of
the nearby galaxy cluster Abell 85, which is currently undergoing at least two
mergers, and in addition shows evidence for gas sloshing which extends out to r
~ 600 kpc. One of the two infalling subclusters, to the south of the main
cluster center, has a dense, X-ray bright cool core and a tail extending to the
southeast. The northern edge of this tail is strikingly smooth and sharp
(narrower than the Coulomb mean free path of the ambient gas) over a length of
200 kpc, while toward the southwest the boundary of the tail is blurred and
bent, indicating a difference in the plasma transport properties between these
two edges. The thermodynamic structure of the tail strongly supports an overall
northwestward motion. We propose, that a sloshing-induced tangential, ambient,
coherent gas flow is bending the tail eastward. The brightest galaxy of this
subcluster is at the leading edge of the dense core, and is trailed by the tail
of stripped gas, suggesting that the cool core of the subcluster has been
almost completely destroyed by the time it reached its current radius of r ~
500 kpc. The surface-brightness excess, likely associated with gas stripped
from the infalling southern subcluster, extends toward the southeast out to at
least r_500 of the main cluster, indicating that the stripping of infalling
subclusters may seed gas inhomogeneities. The second merging subcluster appears
to be a diffuse non-cool core system. Its merger is likely supersonic with a
Mach number of ~ 1.4.
