Chandra Observations of the Central Region of A3112

We present the results of a Chandra observation of the central region of A3112. This cluster has a powerful radio source in the center and was believed to have a strong cooling flow. The X-ray image shows that the intracluster medium (ICM) is distributed smoothly on large scales but has significant deviations from a simple concentric elliptical isophotal model near the center. Regions of excess emission appear to surround two lobelike radio-emitting regions. This structure probably indicates that hot X-ray gas and radio lobes are interacting. From an analysis of the X-ray spectra in annuli, we found clear evidence for a temperature decrease and abundance increase toward the center. The X-ray spectrum of the central region is consistent with a single-temperature thermal plasma model. The contribution of X-ray emission from a multiphase cooling flow component with gas cooling to very low temperatures locally is limited to less than 10% of the total emission. However, the whole cluster spectrum indicates that the ICM is cooling significantly as a whole, but only in a limited temperature range (≥2 keV). Inside the cooling radius the conduction timescales based on the Spitzer conductivity are shorter than the cooling timescales. We detect an X-ray point source in the cluster center that is coincident with the optical nucleus of the central cD galaxy and the core of the associated radio source. The X-ray spectrum of the central point source can be fitted by a 1.3 keV thermal plasma and a power-law component whose photon index is 1.9. The thermal component is probably plasma associated with the cD galaxy. We attribute the power-law component to the central active galactic nucleus.