Galactic-scale Feedback Observed in the 3C 298 Quasar Host Galaxy

Abstract

We present high angular resolution multiwavelength data of the 3C 298 radio-loud quasar host galaxy ( z = 1.439) taken using the W.M. Keck Observatory OSIRIS integral field spectrograph (IFS) with adaptive optics, the Atacama Large Millimeter/submillimeter Array (ALMA), the Hubble Space Telescope ( HST ) WFC3, and the Very Large Array (VLA). Extended emission is detected in the rest-frame optical nebular emission lines H β , [O iii ], H α , [N ii ], and [S ii ], as well as in the molecular lines CO ( J = 3−2) and ( J = 5−4). Along the path of the relativistic jets of 3C 298, we detect conical outflows in ionized gas emission with velocities of up to 1700  and an outflow rate of 450–1500  extended over 12 kpc. Near the spatial center of the conical outflow, CO ( J = 3−2) emission shows a molecular gas disk with a rotational velocity of ±150 and total molecular mass ( ) of . On the blueshifted side of the molecular disk, we observe broad extended emission that is due to a molecular outflow with a rate of 2300  and depletion timescale of 3 Myr. We detect no narrow H α  emission in the outflow regions, suggesting a limit on star formation of 0.3 . Quasar-driven winds are evacuating the molecular gas reservoir, thereby directly impacting star formation in the host galaxy. The observed mass of the supermassive black hole is , and we determine a dynamical bulge mass of . The bulge mass of 3C 298 lies 2–2.5 orders of magnitude below the expected value from the local galactic bulge—supermassive black hole mass ( ) relationship. A second galactic disk observed in nebular emission is offset from the quasar by 9 kpc, suggesting that the system is an intermediate-stage merger. These results show that galactic-scale negative feedback is occurring early in the merger phase of 3C 298, well before the coalescence of the galactic nuclei and assembly on the local relationship.