UNbiased correction relations for galaxy cluster properties derived from chandra and XMM-newton

Abstract

We use a sample of 62 clusters of galaxies to investigate the discrepancies between the gas temperature and total mass within r 500 from XMM-Newton and Chandra data. Comparisons of the properties show that (1) both the de-projected and projected temperatures determined by Chandra are higher than those of XMM-Newton and there is a good linear relationship for the de-projected temperatures: T Chandra = 1.25 × T XMM-0.13. (2) The Chandra mass is much higher than the XMM-Newton mass with a bias of 0.15 and our mass relation is log10 M Chandra = 1.02 × log10 M XMM+0.15. To explore the reasons for the discrepancy in mass, we recalculate the Chandra mass (expressed as Mmo/dCh ) by modifying its temperature with the de-projected temperature relation. The results show that is closer to the XMM-Newton mass with the bias reducing to 0.02. Moreover, Mmo/dCh are corrected with the r500 measured by XMM-Newton and the intrinsic scatter is significantly improved with the value reducing from 0.20 to 0.12. These mean that the temperature bias may be the main factor causing the mass bias. Finally, we find that Mmo/dCh is consistent with the corresponding XMM-Newton mass derived directly from our mass relation at a given Chandra mass. Thus, the de-projected temperature and mass relations can provide unbiased corrections for galaxy cluster properties derived from Chandra and XMM-Newton.