Suzaku Observations of the Merging Cluster Abell 85: Temperature Map and
  Impact Direction
  To investigate the present situation of the merging in the southern outer
region of Abell 85, we carried out long (~100 ks) observations with Suzaku, and
produced an X-ray hardness ratio map. We found a high hardness ratio peak in
the east side of a subcluster located in the south of the cluster; an X-ray
spectrum of the region including this peak indicates a high temperature of ~8.5
keV. This hot spot has not been reported so far. We consider that this hot spot
is a postshock region produced by the infall of the subcluster from the
southwest. By using the Rankine--Hugoniot jump conditions for shocks, the Mach
number and the infall velocity of the subcluster are obtained as 1.5 +/- 0.2
and 1950^{+290}_{-280} km s^{-1}, respectively, in the case of merging with the
subcluster from the southwest direction. By using the redshift difference
between the A 85 and the subcluster obtained from optical observations, the
angle between the line of sight and the direction of the motion of the
subcluster is estimated to be 75^{+7}_{-8} degrees. We estimate the kinetic
energy of the subcluster and the energy used for intracluster medium (ICM)
heating to be ~10^{63} and \lesssim 8 \times 10^{60} erg, respectively. This
shows that the deceleration of the subcluster by ICM heating has been
negligibly small.
