http://arxiv.org/abs/2203.06203
Dusty quasars might be in a young stage of galaxy evolution with prominent quasar feedback. We study a population of luminous, extremely red quasars at redshifts $z\sim$~2–4 that has a suite of extreme spectral properties that may all be related to exceptionally powerful quasar-driven outflows. We present Keck/KCWI observations of the reddest known ERQ, at $z=$\,2.3184, with an extremely fast [\ion{O}{III}]~$\lambda$5007 outflow at $\sim$6000~km~s$^{-1}$. The Ly$\alpha$ halo spans $\sim$100~kpc. The halo is kinematically quiet, with velocity dispersion $\sim$300~km~s$^{-1}$ and no broadening above the dark matter circular velocity down to the spatial resolution $\sim$6~kpc from the quasar. We detect spatially-resolved \ion{He}{II}~$\lambda$1640 and \ion{C}{IV}~$\lambda$1549 emissions with kinematics similar to the Ly$\alpha$ halo and a narrow component in the [\ion{O}{III}]~$\lambda$5007. Quasar reddening acts as a coronagraph allowing views of the innermost halo. A narrow Ly$\alpha$ spike in the quasar spectrum is inner halo emission, confirming the broad \ion{C}{IV}~$\lambda$1549 in the unresolved quasar is blueshifted by $2242$~km~s$^{-1}$ relative to the halo frame. We propose the inner halo is dominated by past/moderate-speed outflow and the outer halo dominated by inflow. The high central concentration of the surface brightness and the circularly symmetric morphology of the inner halo are consistent with the ERQ being young. The \ion{He}{II}~$\lambda$1640/Ly$\alpha$ ratio of the inner halo and the asymmetry level of the overall halo are dissimilar to Type II quasars, implying central ionizing photons can escape along the line of sight. While quasar dominates the ionization, we find no evidence of mechanical quasar feedback on circumgalactic scales.
M. Lau, F. Hamann, J. Gillette, et. al.
Tue, 15 Mar 22
79/108
Comments: 20 pages, 18 figures, submitted to MNRAS
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