Vol. 688
4. Extragalactic astronomy

A JVLA, LOFAR, e-Merlin, VLBA, and EVN study of RBS 797: can binary supermassive black holes explain the outburst history of the central radio galaxy?

The study of precessing jets has been a small industry since the first radio imaging studies of SS 433. Inspired by that work, the authors present a new take on the dynamics and evolution using a multiwavelength approach, combining X-ray and radio data, to tease out the history of precessing jets launched from a possible binary supermassive black hole. The structures cover an enormous span of time and length scales, indicating different phases of nuclear activity. The outermost structures are some 30-50 Myr old, while the inner kiloparsec shows what the authors interpret as a precessing structure of variable intensity and alignment that they link to the activity of the central engine on timescales as short as months. The radio and X-ray morphologies provide a new signature of the presence of a binary central beast.