A tidally induced global corrugation pattern in an external disc galaxy
  similar to the Milky Way
  We study the two dimensional (2D) line-of-sight velocity ($V_{\rm los}$)
field of the low-inclination, late-type galaxy VV304a. The resulting 2D
kinematic map reveals a global, coherent and extended perturbation that is
likely associated with a recent interaction with the massive companion VV304b.
We use multi-band imaging and a suite of test particle simulations to quantify
the plausible strength of in-plane flows due to non-axisymmetric perturbations
and show that the observed velocity flows are much too large to be driven
either by spiral structure nor by a bar. We use fully cosmological
hydrodynamical simulations to characterize the contribution from in- and
off-plane velocity flows to the $V_{\rm los}$ field of recently interacting
galaxy pairs like the VV304 system. We show that, for recently perturbed
low-inclination galactic discs, the structure of the residual velocity field,
after subtraction of an axisymmetric rotation model, can be dominated by
vertical flows. Our results indicate that the $V_{\rm los}$ perturbations in
VV304a are consistent with a corrugation pattern. Its $V_{\rm los}$ map
suggests the presence of a structure similar to the Monoceros ring seen in the
Milky Way. Our study highlights the possibility of addressing important
questions regarding the nature and origin of vertical perturbations by
measuring the line-of-sight velocities in low-inclination nearby galaxies.
