A Sunyaev-Zel'dovich map of the massive core in the luminous X-ray cluster RXJ1347-1145

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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, =(12.7⁺².⁹₋₃.₁)× 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 =16.2 ± 3.8 keV. The resulting total mass of the cluster is, under hydrostatic equilibrium, M(r<1 Mpc)=(1.0 ± 0.3) × 10¹⁵ M for a corresponding gas fraction fgas(r<1 Mpc)=(19.5 ± 5.8)%.