Evidence for jet-driven outflows of cold gas: the case of 3C293

© ASTRON

Over the past decade it has become clear that the growth and evolution of galaxies is strongly tied to that of the central supermassive black hole. This is generally attributed to feedback mechanisms which, according to simulations, often take the form of outflows of gas, quenching star formation in the host galaxy and halting accretion onto the central black hole. While there are a number of plausible ways that outflows could be produced, recent results have shown that in some cases, radio jets could be responsible for driving fast outflows of gas. One such example is the nearby radio galaxy 3C293.

While fast outflows have previously been detected in this object using Westerbork (see Morganti et al., 2003), the spatial resolution of these observations was too low to accurately determine the location of the outflow. Using observations from the recently upgraded VLA we detect a fast outflow (~1200 km/s) of neutral gas approximately 0.5 kpc from the central core, suggesting that it is being driven by the radio jet. The image on the left shows the Westerbork radio continuum image of 3C293 overlaid on an optical image depicting the host galaxy. On the right is the new VLA observations where we detect the inner radio lobes on arcsec scales (middle panel) and the corresponding position-velocity diagram highlighting the broad HI absorption (top panel). A higher resolution VLBI image from Beswick et al., 2004 is shown at the bottom for comparison. The horizontal red line marks the axis along which the position-velocity diagram was extracted and the vertical red line indicates the position of the core taken from the VLBI image.

This result is presented in a paper by Elizabeth Mahony, Raffaella Morganti, Bjorn Emonts, Tom Oosterloo and Clive Tadhunter that has been accepted for publication in Monthly Notices of the Royal Astronomical Society. The preprint is also available at http://arxiv.org/abs/1307.4535 .