Suzaku Observations of Abell 1795: Cluster Emission to r200

被引:131
作者
Bautz, Marshall W. [1 ]
Miller, Eric D. [1 ]
Sanders, Jeremy S. [2 ]
Arnaud, Keith A. [3 ]
Mushotzky, Richard F. [3 ]
Porter, F. Scott [3 ]
Hayashida, Kiyoshi [4 ]
Henry, J. Patrick [5 ]
Hughes, John P. [6 ]
Kawaharada, Madoka [7 ]
Makishima, Kazuo [7 ]
Sato, Mitsuhiro [7 ]
Tamura, Takayuki [8 ]
机构
[1] MIT, Kavli Inst Astrophys & Space Res, Cambridge, MA 02139 USA
[2] Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England
[3] NASA, Goddard Space Flight Ctr, Astrophys Sci Div, Greenbelt, MD 20771 USA
[4] Osaka Univ, Grad Sch Sci, Dept Earth & Space Sci, Toyonaka, Osaka 5600043, Japan
[5] Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA
[6] Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08854 USA
[7] Univ Tokyo, Dept Phys, Bunkyo Ku, Tokyo 1130033, Japan
[8] Japan Aerosp Explorat Agcy, Inst Space & Astronaut Sci, Sagamihara, Kanagawa 2298510, Japan
关键词
galaxies: clusters: intracluster medium; galaxies: clusters: individual (Abell 1795); galaxies: clusters: X-rays; X-RAY-CLUSTERS; RELAXED GALAXY CLUSTERS; WIND CHARGE-EXCHANGE; XMM-NEWTON; VIRIAL RADIUS; SOLAR-WIND; SURFACE BRIGHTNESS; GAS TEMPERATURE; PROFILES; MASS;
D O I
10.1093/pasj/61.5.1117
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We report Suzaku observations of the galaxy cluster Abell 1795 that extend to r(200) approximate to 2 Mpc, the radius within which the mean cluster mass density is 200 times the cosmic critical density. These observations are the first to probe the state of the intracluster medium in this object at r > 1.3 Mpc. We sample two disjoint sectors in the cluster outskirts (1.3 Mpc < r < 1.9 Mpc) and detect X-ray emission in only one of them to a limiting (3 sigma) soft X-ray surface brightness of B0.5-2keV = 1.8 x 10(-12) erg s(-1) cm(-2) deg(-2), it level less than 20% of the cosmic X-ray background brightness. We trace the run of temperature with radius at r > 0.4 Mpc and find that it falls relatively rapidly (T-deprojected proportional to r(-0.9)), reaching a value about one third of its peak at the largest radius we can measure it. Assuming the intracluster medium is in hydrostatic equilibrium and is polytropic, we find a polytropic index of Gamma = 1.3(-0.2)(+0.3) and we estimate a mass of (4.1(-0.3)(+0.5)) x 10(14) M-circle dot within 1.3 Mpc, somewhat (2.7 sigma) lower than that reported by previous observers. However, our observations provide evidence for departure from hydrostatic equilibrium at radii as small as r similar to 1.3 Mpc approximate to r(500) in this apparently regular and symmetrical cluster.
引用
收藏
页码:1117 / 1133
页数:17
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