2001ApJ...561L.165F

We present a two-dimensional temperature map of the Perseus Cluster based on multipointing observations with the ASCA Gas Imaging Spectrometer, covering a region with a diameter of ∼2°. By correcting for the effect of the X-ray telescope response, the temperatures were estimated from hardness ratios, and the complete temperature structure of the cluster with a spatial resolution of about 100 kpc was obtained for the first time. There is an extended cool region with a diameter of ∼20' and kT∼5 keV about 20' east of the cluster center. This region also shows higher surface brightness and is surrounded by a large ringlike hot region with kT≳7 keV and is likely to be a remnant of a merger with a poor cluster. Another extended cool region is extending outward from the IC 310 subcluster. These features and the presence of several other hot and cool blobs suggest that this rich cluster has been formed as the result of a repetition of many subcluster mergers.