XMM-Newton observation of the most X-ray-luminous galaxy cluster RX J1347.5-1145

We report on an XMM-Newton observation of RX J1347.5-1145 (z = 0.451), the most luminous X-ray cluster of galaxies currently known, with a luminosity L-X = 6.0 +/- 0.1 x 10(45) erg/s in the [2 - 10] keV energy band. We present the first temperature map of this cluster, which shows a complex structure. It identifies the cool core and a hot region at radii 50 - 200 kpc to south-east of the main X-ray peak, at a position consistent with the subclump seen in the X-ray image. This structure is probably an indication of a submerger event. Excluding the data of the south-east quadrant, the cluster appears relatively relaxed and we estimate a total mass within 1.7 Mpc of 2.0 +/- 0.4 x 10(15) M-.. We find that the overall temperature of the cluster is kT = 10.0 +/- 0.3 keV. The temperature profile shows a decline in the outer regions and a drop in the centre, indicating the presence of a cooling core which can be modelled by a cooling flow model with a minimum temperature similar to 2 keV and a very high mass accretion rate,. (M) over dot similar to 1900 M-. yr. We compare our results with previous observations from ROSAT, ASCA and Chandra.