Study of asymmetric brightness distribution in distant clusters of galaxies Original Research Article

We present results of the study on the spatial asymmetric distribution of the X-ray surface brightness and the plasma temperature in distant clusters of galaxies (z>0.1) with ASCA. Though most of distant clusters we analyzed (∼ 6 clusters) show spherical symmetric shape, we found the significant excess from the iso-thermal beta model in two clusters. The temperature in that region seems to be different from the average. Recently asymmetric patterns in the surface brightness distribution and the plasma temperature have been detected even in the clusters had known as the spherical symmetric shaped cluster. This non-spherical symmetric distribution has been also suggested by gravitational lensing image analyses and multi-components of a velocity dispersion. It may be caused by a cluster-cluster merging or in-falling groups.