Temperature variation in the cluster of galaxies Abell 115 studied with ASCA

Abell 115 exhibits two distinct peaks in the surface brightness distribution. Observation with ASCA shows a significant temperature variation in this cluster, confirmed by a hardness ratio analysis and spectral fits. A linking region between the main cluster and subcluster shows a high temperature compared with other regions. Two possibilities are examined as the cause of the temperature variation: cooling flows in the main cluster and a shock heating due to the collision of the subcluster into the main system. Spectral fits with cooling how models to the main-cluster data show a mass-deposition rate less than 419 M. yr(-1). Temperatures in the main cluster, the linking region, and the subcluster are estimated by correcting for the effects of X-ray telescope response as 4.9(-0.6)(+0.7), 11(-4)(+12), and 5.2(-1.0)(+1.4) keV, respectively. The high temperature in the linking region implies that Abell 115 is indeed a merger system, with possible contribution from cooling hows on the temperature structure.