R. Shibata, H. Honda, M. Ishida, T. Ohashi and K. Yamashita

Abstract

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 flow models to the main-cluster data show a mass-deposition rate less than 419 M_solar 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^+0.7_-0.6, 11^+12_-4, and 5.2^+1.4_-1.0 keV, respectively. The high temperature in the linking region implies that Abell 115 is indeed a merger system, with possible contribution from cooling flows on the temperature structure.