paper

ASCA Compilation of X-Ray Properties of Hot Gas in Elliptical Galaxies and Galaxy Clusters: Two Breaks in the Temperature Dependences

arXiv:astro-ph/0411745 · doi:10.1093/pasj/56.6.965

Abstract

Utilizing ASCA archival data of about 300 objects of elliptical galaxies, groups, and clusters of galaxies, we performed systematic measurements of the X-ray properties of hot gas in their systems, and compiled them in this paper. The steepness of the luminosity--temperature (LT) relation, , in the range of 1.5--15 keV is , consistent with previous measurements. In the relation, we find two breaks at around ICM temperatures of 1 keV and 4 keV: above 4 keV, in 1.5--5 keV, and below 1.5 keV. Such two breaks are also evident in the temperature and size relation. The steepness in the LT relation at keV is consistent with the scale-relation derived from the CDM model, indicating that the gravitational effect is dominant in richer clusters, while poorer clusters suffer non-gravity effects. The steep LT relation below 1 keV is almost attributed to X-ray faint systems of elliptical galaxies and galaxy groups. We found that the ICM mass within the scaling radius follows the relation of from X-ray faint galaxies to rich clusters. Therefore, we speculate that even such X-ray faint systems contain a large-scale hot gas, which is too faint to detect.

59 pages, 20 figures, to appear in PASJ 56 No.6 Pdf documents including complete tables are available as http://www-heaf.hepl.hiroshima-u.ac.jp/~fukazawa/icmmas-sup.pdf

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