We present two-dimensional temperature maps of four nearby bright clusters of galaxies A1060, AWM7, the Centaurus cluster, and the Perseus cluster, based on multi-pointing observations with the ASCA GIS. The pointing fields cover the whole cluster regions of 1 - 1.8° corresponding to about 2-3 h-150 Mpc. The temperatures were derived from hardness ratios, including corrections for the effects of the XRT response. The central cool components were subtracted for the Centaurus and the Perseus clusters, and metallicity gradients in AWM7, the Centaurus and the Perseus clusters were also corrected.
The intracluster medium in A1060 and AWM7 is almost isothermal from the center to the outer regions with temperatures of 3.3 and 3.9 keV, respectively. The Centaurus cluster exhibits remarkable hot region within about 30' south-east from the cluster center, showing a temperature increase of +0.8 keV from the surrounding level of 3.5 keV. There are also some cool regions with lower temperatures by -1.3 keV toward the cluster edge. The temperature map of the Perseus shows more complex structure in the whole cluster region. There is an extended cool region with a diameter of ∼20' and kT∼ 5 keV at about 20' east from the cluster center. This region also shows higher surface brightness, and is surrounded by a large ring-like hot region with kT ≥7 keV. Another extended cool region is extending outward from the IC 310 subcluster.
The observed results indicate that A1060 and AWM7 have not experienced merging processes for recent a few Gyr. The southeast hot region near the cluster center of the Centaurus corresponds to a galaxy subcluster region from optical observations. These features suggest that a strong merger has occurred in the recent ∼1 Gyr, and that the central cool component has survived it. For the Perseus cluster, the presence of several other hot and cool blobs suggests that this rich cluster has been formed as a result of a repetition of many subcluster mergers.