High redshift X – ray galaxy clusters . I . The impact of point sources on the cluster properties

Context. The current generation of X-ray observatories like Chandra allows studies with very fine spatial details. It is now possible to resolve X–ray point sources projected into the cluster diffuse emission and exclude them from the analysis to estimate the " correct " X–ray observables. Aims. We wish to verify the incidence of point sources on the cluster thermal emission and to evaluate the impact of their non-thermal emission on the determination of cluster properties. Methods. To these ends we use a sample of 18 high-z (0.250.7 where temperature and luminosity increase up to 24% and 22%, respectively. Conclusions. The conclusions are that point sources should be removed to correctly estimate the cluster properties. However the inclusion of the point sources does not impact significantly the slope and normalization of the L bolT relationship since for each cluster the correction to be applied to T and L bol produces a moderate shift in the L bol –T plane almost parallel to the best-fit of the " correct " L bol –T relation.