We have mapped the Sunyaev-Zel'dovich decrement (hereafter SZ) in the direction of the most luminous X-ray cluster known to date, RXJ1347-1145, at z=0.451. This has been achieved with an angular resolution of about 23'' using the Diabolo photometer running on the IRAM 30 meter radio telescope. We present here a map of the cluster central region at 2.1mm. The Comptonization parameter towards the cluster center, $\yc=(12.7^{ +2.9}_{ -3.1})\times 10^{ -4}$, corresponds to the deepest SZ decrement ever observed. Using the gas density distribution derived from X-ray data, this measurement implies a gas temperature $\te=16.2 \pm 3.8$ keV. The resulting total mass of the cluster is, under hydrostatic equilibrium, $M(r<1 Mpc)=(1.0 \pm 0.3) \times 10^{ 15} M_\odot$ for a corresponding gas fraction $f_{ gas}(r<1 Mpc)=(19.5 \pm 5.8)%$.
Categories: astro-ph