The XMM–NEWTON ? Project: I. The X-ray luminosity – temperature relation at z>0.4

We describe XMM-Newton Guaranteed Time observations of a sample of eight high redshift (0.45 < z < rvirial) bolometric luminosities, performed ß-model fits to the radial surface profiles and made spectral fits to a single temperature isothermal model. We describe data analysis techniques that pay particular attention to background mitigation. We have also estimated temperatures and luminosities for two known clusters (Abell 2246 and RXJ1325.0-3814), and one new high redshift cluste r candidate (XMMU J084701.8 +345117), that were detected o ff-axis. Characterizing the L x - Tx relation as L x = L 6 ( T 6keV ) a , we find L 6 = 15 . 9 + 7 . 6 - 5 . 2 × 1044erg s - 1 and a =2.7 ±0.4 for an ? ? = 0 . 0 , ? M = 1 .0, H0 = 50 km s - 1 Mpc - 1 cosmology at a typical redshift z ~ 0 .55. Comparing with the low redshift study by Markevitch, 1998, we find a to be in agreement, and assuming L x - Tx to evolve as (1 + z ) A , we find A =0.68 ±0.26 for the same cosmology and A = 1 .52 + 0 .26 - 0 .27 for an ? ? = 0 . 7 , ? M = 0 . 3 cosmology. Our A values are very similar to those found previously by Vikhlinin et al., 2002 using a compilation of Chandra observations of 0 .39 < z < 1 .26 clusters. We conclude that there is now evidence from both XMM-Newton and Chandra for an evolutionary trend in the L x - Tx relation. This evolution is significantly below the level expected from the predictions of the self-similar model for an ? ? = 0 . 0 , ? M = 1 .0, cosmology, but consistent with self-similar model in an ? ? = 0 . 7 , ? M = 0 . 3 cosmology. Our observations lend support to the robustness and completeness of the SHARC and 160SD surveys.