SUZAKU OBSERVATIONS OF THE OUTSKIRTS OF A1835: DEVIATION FROM HYDROSTATIC EQUILIBRIUM
- Department of Physics, Tokyo University of Science, 1-3 Kagurazaka, Shinjyuku-ku, Tokyo 162-8601 (Japan)
- Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China)
- Argelander-Institut fuer Astronomie, Universitaet Bonn, Auf dem Huegel 71, D-53121 Bonn (Germany)
- Department of Physics, University of Helsinki, Gustaf Haellstroemin katu 2a, FI-00014 Helsinki (Finland)
- Department of Earth and Space Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan)
- Department of Physical Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan)
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan)
- Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)
- Department of Physics, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397 (Japan)
- Department of Physics, Nara Women's University, Kitauoyanishi-machi, Nara, Nara 630-8506 (Japan)
- Department of Physics, Yamagata University, Yamagata, Yamagata 990-8560 (Japan)
We present results of four-pointing Suzaku X-ray observations (total {approx}200 ks) of the intracluster medium (ICM) in the A1835 galaxy cluster (kT {approx} 8 keV, z = 0.253) out to the virial radius (r{sub vir} {approx} 2.9 Mpc) and beyond. Faint X-ray emission from the ICM out to r{sub vir} is detected. The temperature gradually decreases with radius from {approx}8 keV in the inner region to {approx}2 keV at r{sub vir}. The entropy profile is shown to flatten beyond r{sub 500}, in disagreement with the r {sup 1.1} dependence predicted from the accretion shock heating model. The thermal pressure profile in the range 0.3r{sub 500} {approx}< r {approx}< r{sub vir} agrees well with that obtained from the stacked Sunyaev-Zel'dovich effect observations with the Planck satellite. The hydrostatic mass profile in the cluster outskirts (r{sub 500} {approx}< r {approx}< r{sub vir}) falls well short of the weak-lensing one derived from Subaru/Suprime-Cam observations, showing an unphysical decrease with radius. The gas mass fraction at r{sub vir} defined with the lensing total mass agrees with the cosmic baryon fraction from the Wilkinson Microwave Anisotropy Probe seven-year data. All these results indicate, rather than the gas-clumping effect, that the bulk of the ICM in the cluster outskirts is far from hydrostatic equilibrium and infalling matter retained some of its kinetic energy. Finally, combining with our recent Suzaku and lensing analysis of A1689, a cluster of similar mass, temperature, and redshift, we show that the cluster temperature distribution in the outskirts is significantly correlated with the galaxy density field in the surrounding large-scale environment at (1-2)r{sub vir}.
- OSTI ID:
- 22167513
- Journal Information:
- Astrophysical Journal, Vol. 766, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
Similar Records
TURBULENCE IN THE SUPERMODEL: MASS RECONSTRUCTION WITH NONTHERMAL PRESSURE FOR A1835
(Suzaku