The impact of cooling flows on the TX-LBol relation for the most luminous clusters

Abstract

We examine the effects of cooling flows on the T X -L Bol relation for a sample of the most X-ray luminous (L Bol > 10 45 erg s 1 ) clusters of galaxies known. Using high-quality ASCA X-ray spectra and ROSAT images we explicitly account for the effects of cooling flows on the X-ray properties of the clusters and show that this reduces the previously noted dispersion in the T X -L Bol relationship. More importantly, the slope of the relationship is flattened from L Bol T 3 X to approximately L Bol T 2 X , in agreement with recent theoretical models which include the effects of shocks and pre-heating on the X-ray gas. We find no evidence for evolution in the T X -L Bol relation within z 0:3. Our results demonstrate that the effects of cooling flows must be accounted for before cosmological parameters can be determined from X-ray observations of clusters. The results presented here should provide a reliable basis for modelling the T X -L Bol relation at high X-ray luminosities.