Minor-merger induced star formation rejuvenation in an elliptical radio-loud quasar host, 3C 59

TL;DR

This study presents evidence that minor mergers with satellite galaxies can rejuvenate star formation in an elliptical radio-loud quasar host, 3C 59, highlighting the role of such interactions in galaxy evolution.

Contribution

It provides a detailed case study linking minor mergers to star formation rejuvenation and quasar activity in an elliptical galaxy, with implications for galaxy growth and quenching processes.

Findings

Recent star formation in 3C 59 within the last 500 Myr.

Satellite galaxies show morphological disturbances and low star formation.

3C 59 has a larger effective radius compared to typical galaxies.

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 shows significant star formation rejuvenation within the past 500 Myr, before which remains rather quiescent for most of the cosmic time. Three nearest satellite galaxies of 3C 59 exhibit significant morphological disturbances, and two of them present strong tidal tails pointing towards 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 ($R_{\rm e}$) than local late-type galaxies, while 3C 59 has significantly larger $R_{\rm e}$ 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.