Jellyfish: Resolving the kinematics of extreme ram-pressure stripping at
  $z\sim0.3$
  We present and discuss results from the first spatially resolved kinematic
study of ram-pressure stripping of a massive late-type galaxy at intermediate
redshifts. Our target, the spectacular "jellyfish" galaxy A1758N\_JFG1, was
previously identified as a fast-moving member of the equal-mass merger A1758N
($z=0.28$) with a star-formation rate of 48 M$_\odot$ yr$^{-1}$, far above the
galaxy main sequence. IFU data obtained by us unambiguously confirm
ram-pressure stripping as the physical mechanism driving the optical morphology
and high star-formation rate of this system by revealing extended
[\ion{O}{2}]$\lambda$3727\AA\ emission up to 40 kpc (in projection) downstream,
as well as an ordered radial-velocity field generated by (a) conservation of
angular momentum of the interstellar gas stripped from the edge of the galactic
disk and (b) drag forces exerted by the intra-cluster medium on the "tentacles"
of stripped material. We find no evidence of significant nuclear activity in
A1758N\_JFG1, although an AGN might, at this early stage of the stripping
process, be obscured by high column densities of gas and dust near the galactic
core. Finally, our exploration of possible trajectories of A1758N\_JFG1 found
solutions consistent with the notions (a) that the A1758N merger proceeds along
an axis that is substantially inclined with respect to the plane of the sky and
(b) that A1758N\_JFG1 participated in the merger, rather than having been
accreted independently from the field.
