We explore the kinematics of 27 z~6 quasar host galaxies observed in
[CII]-158 micron ([CII]) emission with the Atacama Large
Millimeter/sub-millimeter Array at a resolution of ~0.25''. We find that nine
of the galaxies show disturbed [CII] emission, either due to a close companion
galaxy or recent merger. Ten galaxies have smooth velocity gradients consistent
with the emission arising from a gaseous disk. The remaining eight quasar host
galaxies show no velocity gradient, suggesting that the gas in these systems is
dispersion-dominated. All galaxies show high velocity dispersions with a mean
of 129+-10 km/s. To provide an estimate of the dynamical mass within twice the
half-light radius of the quasar host galaxy, we model the kinematics of the
[CII] emission line using our publicly available kinematic fitting code,
qubefit. This results in a mean dynamical mass of 5.0+-0.8(+-3.5) x 10^10 Msun.
Comparison between the dynamical mass and the mass of the supermassive black
hole reveals that the sample falls above the locally derived bulge mass--black
hole mass relation at 2.4sigma significance. This result is robust even if we
account for the large systematic uncertainties. Using several different
estimators for the molecular mass, we estimate a gas mass fraction of >10%,
indicating gas makes up a large fraction of the baryonic mass of z~6 quasar
host galaxies. Finally, we speculate that the large variety in [CII] kinematics
is an indication that gas accretion onto z~6 super massive black holes is not
caused by a single precipitating factor.

本研究利用 Atacama 大型毫米 / 亚毫米阵列研究了 27 个 z ~ 6 类星体宿主星系的运动学，发现不同的 [CII] 动力学表现形式，其中 9 个星系表现为紊乱 [CII] 发射，表明与近距离星系相互作用或最近合并有关；10 个星系具有光滑的速度梯度，而其他八个则没有速度梯度，表明在这些系统中的气体是以分散为主导的。所有的星系都表现出高速度色散，其平均值为 129+-10km/s。最终，对这些 [CII] 发射线的运动学进行建模，得出了平均动力学质量约为 5.0+-0.8 (+-3.5)×10^10Msun，同时显示样本中超大质量黑洞质量与星系上的动力学质量相违离。此外，我们通过几种不同的方法估算分子质量，发现气体质量分数大于 10％，表明气体占了 z~6 类星体宿主星系重子质量的很大一部分；最后，我们推测，种类繁多的 [CII] 运动学形式表明 z~6 超大质量黑洞的气体吸积并非由单一的突发因素引起。