We present ALMA detections of the [ C ii ] 158 \mu m emission line and the underlying far-infrared continuum of three quasars at 6.6 < z < 6.9 selected from the VIKING survey .
The [ C ii ] line fluxes range between 1.6–3.4 Jy km s ^ { -1 } ( [ C ii ] luminosities \sim ( 1.9 - 3.9 ) \times 10 ^ { 9 } L _ { \sun } ) .
We measure continuum flux densities of 0.56–3.29 mJy around 158 \mu m ( rest-frame ) , with implied far-infrared luminosities between ( 0.6 - 7.5 ) \times 10 ^ { 12 } L _ { \sun } and dust masses M _ { d } = ( 0.7 - 24 ) \times 10 ^ { 8 } M _ { \sun } .
In one quasar we derive a dust temperature of 30 ^ { +12 } _ { -9 } K from the continuum slope , below the canonical value of 47 K. Assuming that the [ C ii ] and continuum emission are powered by star formation , we find star-formation rates from 100–1600 M _ { \sun } yr ^ { -1 } based on local scaling relations .
The L _ { \mathrm { [ CII ] } } / L _ { \mathrm { FIR } } ratios in the quasar hosts span a wide range from ( 0.3 - 4.6 ) \times 10 ^ { -3 } , including one quasar with a ratio that is consistent with local star-forming galaxies .
We find that the strength of the L _ { \mathrm { [ CII ] } } and 158 \mu m continuum emission in z \gtrsim 6 quasar hosts correlate with the quasar ’ s bolometric luminosity .
In one quasar , the [ C ii ] line is significantly redshifted by \sim 1700 km s ^ { -1 } with respect to the Mg ii broad emission line .
Comparing to values in the literature , we find that , on average , the Mg ii is blueshifted by 480 km s ^ { -1 } ( with a standard deviation of 630 km s ^ { -1 } ) with respect to the host galaxy redshift , i.e .
one of our quasars is an extreme outlier .
Through modeling we can rule out a flat rotation curve for our brightest [ C ii ] emitter .
Finally , we find that the ratio of black hole mass to host galaxy ( dynamical ) mass is higher by a factor 3–4 ( with significant scatter ) than local relations .