INTEGRAL Observations of the Perseus cluster

Abstract

We present the results of a 500 ksec observation of the Perseus cluster with INTEGRAL, with the aim of investigating the possible diffuse non-thermal component detected in a previous Chandra observation. In the 3-20 keV band with the JEM-X instrument, we detect the source with high significance and resolve it spatially. Above 20 keV with IBIS/ISGRI, we find that the source is point-like, and the cluster could be detected up to 120 keV. From the broad-band ISGRI/JEM-X spectrum, although we detect a non-thermal component, we find that the high-energy flux is variable and is consistent with the extrapolation of the 2-10 keV flux of the central AGN, NGC 1275. The extrapolation of the non-thermal component claimed from Chandra data exceeds the INTEGRAL spectrum by a factor of 3.