[CII] and CO Emission Along the Bar and Counter-Arms of NGC 7479
  We present new SOFIA [CII] and ALMA CO(J=1-0) observations of the nearby
asymmetric barred spiral galaxy NGC 7479. The data, which cover the whole bar
of the galaxy and the counter-arms visible in the radio continuum, are analyzed
in conjunction with a wealth of existing visible, infrared, radio, and X-ray
data. As in most normal galaxies, the [CII] emission is generally consistent
with emission from cooling gas excited by photoelectric heating in
photo-dissociation regions. However, anomalously high [CII]/CO ratios are seen
at the two ends of the counter-arms. Both ends show shell-like structures,
possibly bubbles, in H-alpha emission. In addition, the southern end has [CII]
to infrared emission ratios inconsistent with normal star formation. Because
there is little HI emission at this location, the [CII] emission probably
originates in warm shocked molecular gas heated by the interaction of the radio
jet forming the counter-arms with the interstellar medium in the galaxy. At two
other locations, the high [CII]/CO ratios provide evidence for the existence of
patches of CO-dark molecular gas. The [CII] and CO observations also reveal
resolved velocity components along the bar. In particular, the CO emission can
be separated into two components associated to gas along the leading edge of
the bar and gas trailing the bar. The trailing gas component that amounts to
approximately 40% of the gas around the bar region may be related to a minor
merger.
