A multi-wavelength strong lensing analysis of baryons and dark matter in
  the dynamically active cluster AC 114
  Strong lensing studies can provide detailed mass maps of the inner regions
even in dynamically active galaxy clusters. It is shown that proper modelling
of the intracluster medium, i.e. the main baryonic component, can play an
important role. In fact, the addition of a new contribution accounting for the
gas can increase the statistical significance of the lensing model. We propose
a parametric method for strong lensing analyses which exploits multi-wavelength
observations. The mass model accounts for cluster-sized dark matter halos,
galaxies (whose stellar mass can be obtained from optical analyses) and the
intracluster medium. The gas distribution is fitted to lensing data exploiting
prior knowledge from X-ray observations. This gives an unbiased look at each
matter component and allows us to study the dynamical status of a cluster.}The
method has been applied to AC 114, an irregular X-ray cluster. We find positive
evidence for dynamical activity, with the dark matter distribution shifted and
rotated with respect to the gas. On the other hand, the dark matter follows the
galaxy density both for shape and orientation, which hints at its collisionless
nature. The inner region (< 250kpc) is under-luminous in optical bands whereas
the gas fraction (~20+- 5%) slightly exceeds typical values. Evidence from
lensing and X-ray suggests that the cluster develops in the plane of the sky
and is not affected by the lensing over-concentration bias. Despite the
dynamical activity, the matter distribution seems to be in agreement with
predictions from N-body simulations. An universal cusped profile provides a
good description of either the overall or the dark matter distribution whereas
theoretical scaling relations seem to be nicely fitted.
