Exploring the galaxy cluster-group transition regime at high redshifts: Physical properties of two newly detected z > 1 systems

Understand

Context: Multi-wavelength surveys for clusters of galaxies are opening a window on the elusive high-redshift (z>1) cluster population.

• Well controlled statistical samples of distant clusters will enable us to answer questions about their cosmological context, early assembly phases and the thermodynamical evolution of the intracluster medium.
• Aims: We report on the detection of two z>1 systems, XMMU J0302.2-0001 and XMMU J1532.2-0836, as part of the XMM-Newton Distant Cluster Project (XDCP) sample.
• We investigate the nature of the sources, measure their spectroscopic redshift and determine their basic physical parameters.