Radio jets clearing the way through galaxies: the view from HI and molecular gas

摘要

Massive gas outflows are considered a key component in the process of galaxyformation and evolution. Because of this, they are the topic of many studiesaimed at learning more about their occurrence, location and physical conditionsas well as the mechanism(s) at their origin. This contribution presents recentresults on two of the best examples of jet-driven outflows traced by cold andmolecular gas. Thanks to high-spatial resolution observations, we have beenable to locate the region where the outflow occurs. This appears to becoincident with bright radio features and regions where the interaction betweenradio plasma jet and ISM is known to occur, thus strongly supporting the ideaof jet-driven outflows. We have also imaged the distribution of the outflowinggas. The results clearly show the effect that expanding radio jets and lobeshave on the ISM. This appears to be in good agreement with what predicted fromnumerical simulations. Furthermore, the results show that cold gas isassociated with these powerful phenomena and can be formed - likely viaefficient cooling - even after a strong interaction and fast shocks. Thediscovery of similar fast outflows of cold gas in weak radio sources is furtherincreasing the relevance that the effect of the radio plasma can have on thesurrounding medium and on the host galaxy.