Comparison of hydrostatic and lensing cluster mass estimates:a pilot
  study in MACS J0647.7+7015
  The detailed characterization of scaling laws relating the observables of
cluster of galaxies to their mass is crucial for obtaining accurate
cosmological constraints with clusters. In this paper, we present a comparison
between the hydrostatic and lensing mass profiles of the cluster \psz\ at
$z=0.59$. The hydrostatic mass profile is obtained from the combination of high
resolution NIKA2 thermal Sunyaev-Zel'dovich (tSZ) and \xmm\ X-ray observations
of the cluster. Instead, the lensing mass profile is obtained from an analysis
of the CLASH lensing data based on the lensing convergence map. We find
significant variation on the cluster mass estimate depending on the observable,
the modelling of the data and the knowledge of the cluster dynamical state.
This {\bf might} lead to significant systematic effects on cluster cosmological
analyses for which only a single observable is generally used. From this pilot
study, we conclude that the combination of high resolution SZ, X-ray and
lensing data could allow us to identify and correct for these systematic
effects. This would constitute a very interesting extension of the NIKA2 SZ
Large Program.
