Minor-merger-induced Star Formation Rejuvenation in an Elliptical Radio-loud Quasar Host, 3C 59

Abstract We report a rare case where an elliptical radio-loud quasar host, 3C 59, rejuvenates star formation activity through minor mergers with its nearby satellite galaxies. The inferred star formation history of 3C 59 has shown significant star formation rejuvenation within the past 500 Myr, before which it remained rather quiescent for most of the cosmic time. The three nearest satellite galaxies of 3C 59 exhibit significant morphological disturbances, and two of them present strong tidal tails pointing toward 3C 59. In addition, all the satellite galaxies within a projected distance of 200 kpc show low star formation activities. They also have systematically lower effective radius ( R e ) than local late-type galaxies, while 3C 59 has significantly larger R e than both early- and late-type galaxies. All these features suggest that ongoing minor mergers between 3C 59 and its nearby satellites could be causing gas to flow into 3C 59, which induces the star formation rejuvenation and possibly also triggers the quasar activity. The enormous power from the large-scale radio jet of 3C 59 may in turn help keep the halo hot, prevent gas cooling, and further reduce star formation in its satellite galaxies. These results provide important insights into the mass and size growth of central galaxies and star formation quenching of satellite galaxies in galaxy groups.