Статья

X-Ray Probing of the Central Regions of Clusters of Galaxies

Kazuo Makishima1Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku,Tokyo 113-0033 [email protected]Hajime Ezawa3Nobeyama Radio Observatory, National Astronomical Observatory, Minamimaki, Minamisaku, Nagano 384-1305Yasushi Fukazawa1Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku,Tokyo 113-0033 [email protected]Hirohiko Honda5The Institute of Space and Astronautical Science, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 226-8510Yasushi Ikebe6Max-Planck-Institut für extraterrestrische Physik, Postfach 1603, D-85740, Garching, GermanyTuneyoshi Kamae1Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku,Tokyo 113-0033 [email protected]Ken’ich KikuchiKyoko Matsushita6Max-Planck-Institut für extraterrestrische Physik, Postfach 1603, D-85740, Garching, GermanyKazuhiro Nakazawa1Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku,Tokyo 113-0033 [email protected]Takaya Ohashi8Department of Physics, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397Tadayuki Takahashi5The Institute of Space and Astronautical Science, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 226-8510Takayuki TamuraHaiguang Xu10Institute for Space Astrophysics, Shanghai Jiao Tong University, Huashan Road 1954, Shanghai 200030, PRC

2001en

ABI

Аннотация

Abstract The results on ASCA X-ray study of the central regions of medium-richness clusters of galaxies are summarized, while emphasizing the differences between cD and non-cD clusters. The intra-cluster medium (ICM) is likely to consist of two (hot and cool) phases within $\sim 100$kpc of a cD galaxy, where the ICM metallicity is also enhanced. In contrast, the ICM in non-cD clusters appears to be isothermal with a small metallicity gradient right of the center. The gravitational potential exhibits a hierarchical nesting around cD galaxies, while a total mass-density profile with a central cusp is indicated for a non-cD cluster, Abell 1060. The iron-mass-to-light ratio of the ICM decreases toward the center in both types of clusters, although it is radially constant in peripheral regions. The silicon-to-iron abundance ratio in the ICM increases with the cluster richness, but remains close to the solar ratio around cD galaxies. These overall results are interpreted without appealing to the popular cooling-flow hypothesis. Instead, an emphasis is put on the halo-in-halo structure formed around cD galaxies.

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Идентификаторы

DOI: 10.1093/pasj/53.3.401

Цитирования и источники

Цитирований: 2Использованных источников: 0

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