  We perform a combined X-ray and strong lensing analysis of RX J1347.5-1145,
one of the most luminous galaxy clusters at X-ray wavelengths. We show that
evidence from strong lensing alone, based on published VLT and new HST data,
strongly argues in favor of a complex structure. The analysis takes into
account arc positions, shapes and orientations and is done thoroughly in the
image plane. The cluster inner regions are well fitted by a bimodal mass
distribution, with a total projected mass of $M_{tot} = (9.9 \pm 0.3)\times
10^{14} M_\odot/h$ within a radius of $360 \mathrm{kpc}/h$ ($1.5'$). Such a
complex structure could be a signature of a recent major merger as further
supported by X-ray data. A temperature map of the cluster, based on deep
Chandra observations, reveals a hot front located between the first main
component and an X-ray emitting South Eastern sub-clump. The map also unveils a
filament of cold gas in the innermost regions of the cluster, most probably a
cooling wake caused by the motion of the cD inside the cool core region. A
merger scenario in the plane of the sky between two dark matter sub-clumps is
consistent with both our lensing and X-ray analyses, and can explain previous
discrepancies with mass estimates based on the virial theorem.

Astrophysics