Structure of the X-ray-emitting gas in the Hydra A Cluster of galaxies

被引:90
作者
Ikebe, Y
Makishima, K
Ezawa, H
Fukazawa, Y
Hirayama, M
Honda, P
Ishisaki, Y
Kikuchi, K
Kubo, H
Murakami, T
Ohashi, T
Takahashi, T
Yamashita, K
机构
[1] UNIV TOKYO,DEPT PHYS,BUNKYO KU,TOKYO 113,JAPAN
[2] INST SPACE & ASTRONAUT SCI,SAGAMIHARA,KANAGAWA 229,JAPAN
[3] TOKYO METROPOLITAN UNIV,DEPT PHYS,HACHIOJI,TOKYO 19203,JAPAN
[4] NAGOYA UNIV,DEPT PHYS,CHIKUSA KU,NAGOYA,AICHI 46401,JAPAN
关键词
galaxies; clusters; individual (Hydra A); intergalactic medium; X-rays;
D O I
10.1086/304095
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
The temperature and abundance structure in the intracluster medium (ICM) of the Hydra A Cluster of galaxies is studied with ASCA and ROSAT. The effect of the large extended outskirts in the point-spread function of the X-ray telescope on ASCA is included in this analysis, In the X-ray brightness profile, the strong central excess above a single beta model, identified in the Einstein and ROSAT data, is also found in the harder energy band (>4 keV). A simultaneous fit of five annular spectra taken with the GIS instrument shows a radial distribution of the temperature and metal abundance, A significant central enhancement in the abundance distribution is found, while the temperature profile suggests that the ICM is approximately isothermal, with a temperature of similar to 3.5 keV. The ROSAT position-sensitive proportional counter (PSPC spectrum in the central 115 region indicates a significantly lower temperature than the GIS result. A joint analysis of the GIS and PSPC data reveals that the spectra can be described by a two-temperature model as well as by a cooling Bow model, In both cases, the hot-phase gas with a temperature of similar to 3.5 keV occupies more than 90% of the total emission measure within 1.5' from the cluster center. The estimated mass of the cooler (0.5-0.7 kee) component is similar to(2-6) x 10(9) M., which is comparable to the mass of hot halos seen in non-cD ellipticals. The cooling Bow model gives the mass deposition rate of 60 +/- 30 M. yr(-1), an order of magnitude lower than the previous estimation.
引用
收藏
页码:660 / 672
页数:13
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