Highly perturbed molecular gas in infalling cluster galaxies: the case
  of CGCG97-079
  We report on CO (J = 2 - 1) mapping with the IRAM 30-m HERA receiver array of
CGCG 97-079, an irregular galaxy in the merging galaxy cluster Abell 1367 (z =
0.022). We find that $\sim$ 80% of the detected CO (J = 2 - 1) is projected
within a 16 arcsec$^{2}$ (6.5 kpc$^{2}$) region to the north and west of the
optical/NIR centre, with the intensity maximum offset $\sim 10$ arcsec (4 kpc)
NW of the optical/NIR centre and $\sim$ 7 arcsec (3 kpc) south-east of the HI
intensity maximum. Evolutionary synthesis models indicate CGCG 97-079
experienced a burst of star formation $\sim$ 10$^8$ yr ago, most likely
triggered by a tidal interaction with CGCG 97-073. For CGCG 97-079 we deduce an
infall velocity to the cluster of $\sim$ 1000 km s$^{-1}$ and moderate ram
pressure (P$_\mathrm{ram} \sim 10^{-11}$ dyn cm$^{-2}$). The observed offset in
CGCG 97-079 of the highest density HI and CO (J = 2 - 1) from the stellar
components has not previously been observed in galaxies currently undergoing
ram pressure stripping, although previous detailed studies of gas morphology
and kinematics during ram pressure stripping were restricted to significantly
more massive galaxies with deeper gravitational potential wells. We conclude
the observed cold gas density maxima offsets are most likely the result of ram
pressure and/or the high-speed tidal interaction with CGCG 97-073. However ram
pressure stripping is likely to be playing a major role in the perturbation of
lower density gas.
