Galaxy Interactions in Compact Groups I : The Galactic Winds of HCG16
  Using the WiFeS integral field spectrograph, we have undertaken a series of
observations of star-forming galaxies in Compact Groups. In this first paper
dedicated to the project, we present the analysis of the spiral galaxy NGC838,
a member of the Hickson Compact Group 16, and of its galactic wind. Our
observations reveal that the wind forms an asymmetric, bipolar, rotating
structure, powered by a nuclear starburst. Emission line ratio diagnostics
indicate that photoionization is the dominant excitation mechanism at the base
of the wind. Mixing from slow shocks (up to 20%) increases further out along
the outflow axis. The asymmetry of the wind is most likely caused by one of the
two lobes of the wind bubble bursting out of its HI envelope, as indicated by
line ratios and radial velocity maps. The characteristics of this galactic wind
suggest that it is caught early (a few Myr) in the wind evolution sequence. The
wind is also quite different to the galactic wind in the partner galaxy NGC839
which contains a symmetric, shock-excited wind. Assuming that both galaxies
have similar interaction histories, the two different winds must be a
consequence of the intrinsic properties of NGC838 and NGC839 and their
starbursts.
