We present new radio continuum (8 GHz and 1.4 GHz) and H I 21 cm line observations of the Seyfert 2 galaxy IC 5063 (PKS 2048-572) obtained with the Australia Telescope Compact Array (ATCA). The high resolution 8 GHz image reveals a linear triple structure of ∼ 4 (1.5 kpc) in size. This small-scale radio emission shows a strong morphological association with the inner part of the optical emission line region (NLR). It is aligned with the inner dust lane and is oriented perpendicular to the position angle of the optical polarization. We identify the radio nucleus to be the central blob of the radio emission. At 21 cm, very broad (∼ 700 km s −1 ) H I absorption is observed against the strong continuum source. This absorption is almost entirely blueshifted, indicating a fast net outflow, but a faint and narrow redshifted component is also present. In IC 5063 we see clear evidence, both morphological and kinematical, for strong shocks resulting from the interaction between the radio plasma and the interstellar medium in the central few kiloparsecs. However, we estimate the energy flux in the radio plasma to be an order of magnitude smaller than the energy flux emitted in emission lines. Thus, although strong shocks associated with the jet-ISM interaction occur and could contribute locally to the ionization of the NLR, they are unlikely to account solely for the global ionization of the emission line region, particularly at large distances.The main structure of the H I emission is a warped disk associated with the system of dust lanes of ∼ 2 radius (∼ 38 kpc, corresponding to ∼ 5 effective radii). The lack of kinematically disturbed gas (both neutral and ionized) outside the central few kpc, the warped structure of the large scale disk together with the close morphological connection between the inner dust lanes and the large-scale ionized gas, support the idea that the gas at large radii is photoionized by the central region, while shadowing effects are important in defining its X-shaped morphology.From the kinematics of the ionized and of the neutral gas, we find evidence for a dark halo in IC 5063, with very similar properties as observed in some other early-type galaxies.
