The physical properties of the intergalactic gas in rich clusters of galaxies

We perform a statistical analysis of the properties of 170 rich clusters of galaxies. We confirm the existence of correlations between the X-ray luminosity and temperature of the cluster intergalactic medium (IGM) and between the velocity dispersion of the galaxies and the X-ray luminosity of the IGM. In addition, we have found a new anti-correlation between the optical luminosity in Hα and the X-ray luminosity of the cluster IGM: log \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \left( {\frac{{L_{H\alpha } }} {{L_ \odot }}} \right) = a - b\log \left( {\frac{{L_x }} {{L_ \odot }}} \right) $$\end{document}. Clusters form sequences with different values of a but similar values of b.