Young tidal dwarf galaxies cannot be used to probe dark matter in
  galaxies
  The location of dark-matter free, tidal dwarf galaxies (TDGs) in the baryonic
Tully Fisher (bTF) diagram has been used to test cosmological scenarios,
leading to various and controversial results. Using new high-resolution 3D
spectroscopic data, we re-investigate the morpho-kinematics of these galaxies
to verify whether or not they can be used for such a purpose. We find that the
three observed TDGs are kinematically not virialized and show complex
morphologies and kinematics, leading to considerable uncertainties about their
intrinsic rotation velocities and their locations on the bTF. Only one TDG can
be identify as a (perturbed) rotation disk that it is indeed a sub-component of
NGC5291N and that lies at $<$1$\sigma$ from the local bTF relation. It results
that the presently studied TDGs are young, dynamically forming objects, which
are not enough virialized to robustly challenge cosmological scenarios.
