Letter to the Editor

Coma revealed as an extended hard X-rays source by INTEGRAL IBIS/ISGRI

¹ Service d'Astrophysique, CEA-Saclay, 91191 Gif-Sur-Yvette, France e-mail: mrenaud@cea.fr
² APC-UMR 7164, 11 place M. Berthelot, 75231 Paris, France

Received: 7 March 2006
Accepted: 26 April 2006

Abstract

Aims.We report the INTEGRAL/IBISobservations of the Coma Clusterin the hard X-ray/soft γ-raydomain.

Methods.Since the Coma Clusterappears as an extended source, its global intensity and significance cannot be directly extracted with standard coded mask analysis. We used the method of imaging the extended sources with a coded mask telescope developed by Renaud et al. (2006).

Results.The imaging capabilities and the sensitivity of the IBIS/ISGRIcoded mask instrument allows us to identify for the first time the site of the emission above ~15 keV. We have studied the Coma Clustermorphology in the 18–30 keV band and found that it follows the prediction based on X-rayobservations. We also bring constraints on the non-thermal mechanism contribution at higher energies.