The uneven sisters I, NGC 4388 - a strongly constrained ram pressure
  stripping event
  Since the Virgo cluster is the closest galaxy cluster in the northern
hemisphere, galaxy interactions can be observed in it with a kpc resolution.
The spiral galaxy NGC 4388 underwent a ram pressure stripping event ~200 Myr
ago caused by its highly eccentric orbit within the Virgo cluster. This galaxy
fulfills all diagnostic criteria for having undergone active ram pressure
stripping in the recent past: a strongly truncated HI and Halpha disk, an
asymmetric ridge of polarized radio continuum emission, extended extraplanar
gas toward the opposite side of the ridge of polarized radio continuum
emission, and a recent (a few 100 Myr) quenching of the star formation activity
in the outer, gas-free galactic disk. We made dynamical simulations of the ram
pressure stripping event to investigate the influence of galactic structure on
the observed properties of NGC 4388. The combination of a deep optical spectrum
of the outer gas-free region of the galactic disk together with deep HI,
Halpha, FUV, and polarized radio continuum data permits to constrain numerical
simulations to derive the temporal ram pressure profile, the 3D velocity vector
of the galaxy, and the time since peak ram pressure with a high level of
confidence. From the simulations an angle between the ram pressure wind and the
galactic disk of 30 degrees is derived. The galaxy underwent peak ram pressure
~240 Myr ago. The observed asymmetries in the disk of NGC 4388 are not caused
by the present action of ram pressure, but by the resettling of gas that has
been pushed out of the galactic disk during the ram pressure stripping event.
For the detailed reproduction of multi-wavelength observations of a spiral
galaxy that undergoes or underwent a ram pressure stripping event, galactic
structure, i.e. spiral arms, has to be taken into account.
