The search for shock-excited H2 in Virgo spirals experiencing ram
  pressure stripping
  We investigate the presence of shock-excited H2 in four Virgo cluster
galaxies that show clear evidence of ongoing ram pressure stripping.
Mid-infrared (MIR) spectral mapping of the rotational H2 emission lines were
performed using the Infrared Spectrograph (IRS) on board the Spitzer space
telescope. We target four regions along the leading side of galaxies where the
intracluster medium (ICM) appears to be pushing back the individual galaxy's
interstellar medium (ISM). For comparison purposes, we also study two regions
on the trailing side of these galaxies, a region within an edge-on disk and an
extraplanar star-forming region. We find a factor of 2.6 excess of warm H2/PAH
in our sample relative to the observed fractions in other nearby galaxies. We
attribute the H2/PAH excess to contributions of shock-excited H2 which is
likely to have been triggered by ongoing ram pressure interaction in our sample
galaxies. Ram pressure driven shocks may also be responsible for the elevated
fractions of [FeII/NeII] found in our sample.
