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

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 Hβ, [O III], Hα, [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 km s^(-1) and an outflow rate of 450–1500 M⊙ yr^(-1) 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 km s^(-1) and total molecular mass (M_H2) of 6.6 ± 0.36 x 10^9 M⊙. 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 M⊙ yr^(-1) and depletion timescale of 3 Myr. We detect no narrow Hα emission in the outflow regions, suggesting a limit on star formation of 0.3 M⊙ yr^(-1) kpc^(-2). 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 10^(9.37-9.56) M⊙, and we determine a dynamical bulge mass of M_(bulge) = 1-1.7 x 1-^(10) R/1.6 kpc M⊙. 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 (M_(bulge)-M_(BH)) 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 M_(bulge)-M_(BH) relationship.