A Spatially Resolved [CII] Survey of 31 z∼7 Massive Galaxies Hosting Luminous Quasars

The [CII] 158 μm emission line and the underlying far-infrared (FIR) dust continuum are important tracers for studying star formation and kinematic properties of early galaxies. We present a survey of the [CII] emission lines and FIR continua of 31 luminous quasars at z>6.5 using the Atacama Large Millimeter Array (ALMA) and the NOrthern Extended Millimeter Array (NOEMA) at sub-arcsec resolution. This survey more than doubles the number of quasars with [CII] and FIR observations at these redshifts and enables statistical studies of quasar host galaxies deep into the epoch of reionization. We detect [CII] emission in 27 quasar hosts with a luminosity range of L_ [CII]=(0.3-5.5)×10^9 L_⊙ and detect the FIR continuum of 28 quasar hosts with a luminosity range of L_ FIR=(0.5-13.0)×10^12 L_⊙. Both L_ [CII] and L_ FIR are correlated (ρ≃0.4) with the quasar bolometric luminosity, albeit with substantial scatter. The quasar hosts detected by ALMA are clearly resolved with a median diameter of ∼5 kpc. About 40 emission, while the rest show either dispersion-dominated or disturbed kinematics. Basic estimates of the dynamical masses of the rotation-dominated host galaxies yield M_ dyn=(0.1-7.5)×10^11 M_⊙. Considering our findings alongside those of literature studies, we found that the ratio between M_ BH and M_ dyn is about ten times higher than that of local M_ BH-M_ dyn relation on average but with substantial scatter (the ratio difference ranging from ∼0.6 to 60) and large uncertainties.