Non-thermal emission in the core of Perseus: results from a long XMM-Newton observation

¹ IASF-Milano, INAF, via Bassini 15, 20133 Milano, Italy e-mail: silvano@iasf-milano.inaf.it
² Dip. di Astronomia, Università di Bologna, via Ranzani 1, 40127 Bologna, Italy e-mail: fabio.gastaldello@unibo.it
³ INAF, Osservatorio Astronomico di Bologna, via Ranzani 1, Bologna 40127, Italy
⁴ Department of Physics and Astronomy, University of California at Irvine, 4129 Frederick Reines Hall, Irvine, CA 92697-4575, USA

Received: 6 May 2008
Accepted: 21 July 2008

Abstract

We employ a long XMM-Newton observation of the core of the Perseus cluster to validate claims of a non-thermal component discovered with Chandra. From a meticulous analysis of our dataset, which includes a detailed treatment of systematic errors, we find the 2–10 keV surface brightness of the non-thermal component to be less than about 5 10^-16 erg cm^-2 s^-1 arcsec^-2. The most likely explanation for the discrepancy between the XMM-Newton and Chandra estimates is a problem in the effective area calibration of the latter. Our EPIC-based magnetic field lower limits do not disagree with Faraday rotation measure estimates on a few cool cores and with a minimum energy estimate on Perseus. In the not too distant future Simbol-X may allow detection of non-thermal components with intensities more than 10 times lower than those that can be measured with EPIC; nonetheless even the exquisite sensitivity within reach for Simbol-X might be insufficient to detect the IC emission from Perseus.