2017ApJ...834..184C

During a systematic search for supermassive black holes (SMBHs) not in galactic nuclei, we identified the compact, symmetric radio source B3 1715+425 with an emission-line galaxy offset ~8.5 kpc from the nucleus of the brightest cluster galaxy (BCG) in the redshift z = 0.1754 cluster ZwCl 8193. B3 1715+425 is too bright (brightness temperature T_b∼3×10¹⁰ K at observing frequency ν=7.6 GHz) and too luminous (1.4 GHz luminosity L_1.4GHz∼10²⁵ W Hz^–1) to be powered by anything but an SMBH, but its host galaxy is much smaller (∼0.9 kpc×0.6 kpc full width between half-maximum points) and optically fainter (R-band absolute magnitude M_r~-18.2) than any other radio galaxy. Its high radial velocity v_r~1860 km s^–1 relative to the BCG, continuous ionized wake extending back to the BCG nucleus, and surrounding debris indicate that the radio galaxy was tidally shredded passing through the BCG core, leaving a nearly naked SMBH fleeing from the BCG with space velocity v 2000 km s^–1. The radio galaxy has mass M 6×10⁹ M_☉ and infrared luminosity L_IR∼3×10¹¹ L_☉ close to its dust Eddington limit, so it is vulnerable to further mass loss from radiative feedback.