Suzaku Observation of Abell 1689: Anisotropic Temperature and Entropy
  Distributions Associated with the Large-Scale Structure
  (Abridged) We present results of Suzaku observations of the intracluster
medium (ICM) in Abell 1689, combined with complementary analysis of the SDSS
data and weak and strong lensing analysis of Subaru/Suprime-Cam and HST/ACS
observations. Faint X-ray emission from the ICM around the virial radius is
detected at 4.0 sigma significance. We find anisotropic gas temperature and
entropy distributions in cluster outskirts correlated with large-scale
structure of galaxies. The high temperature and entropy region in the
northeastern (NE) outskirts is connected to an overdense filamentary structure.
The outskirt regions in contact with low density void environments have low gas
temperatures and entropies, deviating from hydrostatic equilibrium. These
results suggest that thermalization of the ICM occurs faster along the
filamentary structures than the void regions. A joint X-ray and lensing
analysis shows that the hydrostatic mass is $\sim60-90%$ of spherical lensing
one but comparable to a triaxial halo mass within errors in $0.6r_{2500} \simlt
r \simlt 0.8r_{500}$, and that it is significantly biased as low as $\simlt60%$
within $0.4r_{2500}$, irrespective of mass models. The thermal gas pressure
within $r_{500}$ is, at most, $\sim50$--60% of the total pressure to balance
fully the gravity of the spherical lensing mass, and $\sim30$--40% around the
virial radius. Although these constitute lower limits when one considers the
possible halo triaxiality, these small relative contributions of thermal
pressure would require additional sources of pressure, such as bulk and/or
turbulent motions.
