The jet-ISM interaction in the Outer Filament of Centaurus A

Context. The interaction between the radio plasma ejected by the active nucleus of a galaxy and the surrounding medium is a key process that can have a strong impact on the interstellar medium of the galaxy and hence on galaxy evolution. The closest laboratory where we can observe and investigate this phenomenon is the radio galaxy Centaurus A. About 15 kpc north-east of this galaxy, a particularly complex region is found: the so-called Outer Filament where jet-cloud interactions have been proposed to occur. Aims. We investigate the presence of signatures of jet-ISM interaction by a detailed study of the kinematics of the ionized gas, expanding on previous results obtained from the H i. Methods. We observed two regions of the outer filament with VLT/VIMOS in the IFU observing mode. Emission from Hβ and [O iii] λλ4959,5007Å is detected in both pointings. Results. We found two distinct kinematical components of ionized gas that well match the kinematics of the nearby H i cloud. One component follows the regular kinematics of the rotating gas while the second shows similar velocities to those of the nearby H i component thought to be disturbed by an interaction with the radio jet. Conclusions. We suggest that the ionized and atomic gas are part of the same dynamical gas structure originating as result of the merger that shaped Centaurus A and which is regularly rotating around Centaurus A as proposed by other authors. The gas (ionized and H i) with anomalous velocities is tracing the interaction of the Large-Scale radio Jet with the ISM, suggesting that, althoug