Suzaku X-ray Observations of the Nearest Non-Cool Core Cluster, Antlia:
  Dynamically Young but with Remarkably Relaxed Outskirts
  We present the results of seven Suzaku mosaic observations (>200 ks in total)
of the nearest non-cool core cluster, the Antlia Cluster (or Group), beyond its
degree-scale virial radius in its eastern direction. The temperature is
consistent with the scaled profiles of many other clusters. Its pressure
follows the universal profile. The density slope in its outskirts is
significantly steeper than that of the nearest cool core cluster (Virgo) with a
similar temperature as Antlia, but shallower than those of the massive
clusters. The entropy increases all the way out to R_200, which is consistent
in value with the baseline model predicted by a gravity heating-only mechanism
in the outskirts. Antlia is quite relaxed in this direction. However, the
entropy inside ~R_500 is significantly higher than the baseline model, which is
similar to many other nearby low mass clusters or groups. The enclosed gas-mass
fraction does not exceed the cosmic value out to 1.3R_200. Thus, there is no
evidence of significant gas clumping, electron-ion non-equipartition, or
departure from the hydrostatic equilibrium approximation that are suggested to
explain the entropy and gas fraction anomalies found in the outskirts of some
massive clusters. We also present scaling relations for the gas fraction
(f_gas,200), entropy (K_200), and temperature (T_500) using 22 groups and
clusters with published data in the literature. The enclosed baryon fraction at
R_200 is broadly consistent with the cosmic value. The power law slope of the
K_200-T_500 relation is 0.638+/-0.205. The entropy deficit at R_200 cannot be
fully accounted for by the bias or deviation in the gas fraction.
