On the influence of high energy electron populations on metal abundance estimates in galaxy groups and clusters

¹ Institut d'Astrophysique de Paris, CNRS, UMR 7095, Université Pierre et Marie Curie, 98bis Bd Arago, 75014 Paris, France e-mail: prokhoro@iap.fr
² Moscow Institute of Physics and Technology, Institutskii lane, 141700 Moscow Region, Dolgoprudnii, Russia

Received: 19 February 2009
Accepted: 21 September 2009

Abstract

Aims. Spectral line emissivities have usually been calculated for a Maxwellian electron distribution. But many theoretical works on both galaxy groups and clusters and the solar corona consider modified Maxwellian electron distribution functions when fitting observed X-ray spectra. Here we examine the influence of high energy electron populations on measurements of metal abundances.

Methods. A generalized approach proposed by ourselves is used to calculate the line emissivities for a modified Maxwellian distribution. We study metal abundances in galaxy groups and clusters in which hard X-ray excess emission was observed.

Results. We found that for modified Maxwellian distributions the argon abundance decreases for the HCG 62 group, the iron abundance decreases for the Centaurus cluster, and the oxygen abundance decreases for the solar corona with respect to the case of a Maxwellian distribution. Therefore, metal abundance measurements are a promising tool for testing the presence of high energy electron populations.