We present ALMA band-7 data of the [ C ii ] \lambda 157.74 \mu { m } emission line and underlying far-infrared ( FIR ) continuum for twelve luminous quasars at z \simeq 4.8 powered by fast-growing supermassive black holes ( SMBHs ) .
Our total sample consists of eighteen quasars , twelve of which are presented here for the first time .
The new sources consists of six Herschel /SPIRE detected systems , which we define as ” FIR-bright ” sources , and six Herschel /SPIRE undetected systems , which we define as ” FIR-faint ” sources .
We determine dust masses for the quasars hosts of M _ { dust } \leq 0.2 - 25.0 \times 10 ^ { 8 } M _ { \odot } , implying ISM gas masses comparable to the dynamical masses derived from the [ C ii ] kinematics .
It is found that on average the Mg ii line is blueshifted by \sim 500 { km s } ^ { -1 } with respect to the [ C ii ] emission line , which is also observed when complementing our observations with data from the literature .
We find that all of our ” FIR-bright ” subsample and most of the ” FIR-faint ” objects lie above the main sequence of star forming galaxies at z \sim 5 .
We detect companion sub-millimeter galaxies ( SMGs ) for two sources , both FIR-faint , with a range of projected distances of \sim 20 - 60 kpc and with typical velocity shifts of \left| \Delta v \right| \raisebox { -2.15 pt } { $ \stackrel { < } { \sim } $ } 200 { km% s } ^ { -1 } from the quasar hosts .
Of our total sample of eighteen quasars , 5/18 are found to have dust obscured starforming companions .