The extreme ultraviolet excess emission in five clusters of galaxies revisited

¹ Institut d'Astrophysique de Paris, 98bis Bd Arago, 75014 Paris, France
² Observatoire de la Côte d'Azur, BP 4229, 06304 Nice Cedex 4, France
³ Department of Physics, University of Alabama, Huntsville AL 35899, USA
⁴ Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH, UK

Corresponding author: F. Durret, durret@iap.fr

Received: 18 February 2002
Accepted: 15 May 2002

Abstract

Evidence for excess extreme ultraviolet (EUV) emission over a tail of X-ray gas bremsstrahlung emission has been building up recently, but in some cases remains controversial, mostly due to the moderate quality of the EUV data. In order to improve the signal to noise ratio in the EUV, we have performed the wavelet analysis and image reconstructions for five clusters of galaxies observed both at EUV and X-ray energies with the EUVE and ROSAT satellites respectively. The profiles of the EUV and X-ray reconstructed images all differ at a very large confidence level and an EUV excess over a thermal bremsstrahlung tail is detected in all five clusters (Abell 1795, Abell 2199, Abell 4059, Coma and Virgo) up to large radii. These results, coupled with recent XMM-Newton observations, suggest that the EUV excess is probably non thermal in origin.