SCALING RELATIONS AND X-RAY PROPERTIES OF MODERAIE-LUMINOSITY GALAXY CLUS'IERS FROM 0.3 <z <0.6 WITH XMM-NEWTON

We present new X-ray temperatures and improved X-ray luminosity estimates for 15 new and archival XMM-Newton observations of galaxy clusters at intermediate redshift with mass and luminosities near the galaxy group/cluster division (M-2500 < 2.4 x 10(14) h(70)(-1) M-circle dot, L < 2 x 10(44) erg s(-1), 0.3 < z < 0.6). These clusters have weak-lensing mass measurements based on Hubble Space Telescope observations of clusters representative of an X-ray-selected sample (the ROSAT 1605D survey). The angular resolution of XMM-Newton allows us to disentangle the emission of these galaxy clusters from nearby point sources, which significantly contaminated previous X-ray luminosity estimates for 6 of the 15 clusters. We extend cluster scaling relations between X-ray luminosity, temperature, and weak-lensing mass for low-mass, X-ray-selected clusters out to redshift similar to 0.45. These relations are important for cosmology and the astrophysics of feedback in galaxy groups and clusters. Our joint analysis with a sample of 50 clusters in a similar redshift range but with larger masses (M-500 < 21.9 x 10(14) M-circle dot, 0.15 <= z <= 0.55) from the Canadian Cluster Comparison Project finds that within r(2500), M proportional to L-0.44 +/- 0.05, T proportional to L-0.23 +/- 0.02, and M a T'9 02 The estimated intrinsic scatter in the M L relation for the combined sample is reduced to (sigma)log(M/L) = 0.10, from (sigma)log(M/L)= 0.26 with the original ROSAT measurements. We also find an intrinsic scatter for the T L relation, (sigma)log(M/L = 0.07 0.01.