We present Plateau de Bure Interferometer ( PdBI ) observations of far infra-red emission lines in BRI 0952-0115 ( B0952 ) , a lensed QSO at z=4.4 powered by a super-massive black hole ( M _ { BH } = 2 \times 10 ^ { 9 } M _ { \odot } ) .
In this source , the resolved map of the [ CII ] emission at 158 \mu m allows us to reveal the presence of a companion galaxy , located at \sim 10 kpc from the QSO , undetected in optical observations .
From the CO ( 5-4 ) emission line properties we infer a stellar mass M _ { * } < 2.2 \times 10 ^ { 10 } M _ { \odot } , which is significantly smaller than the one found in local galaxies hosting black holes with similar masses ( M _ { * } \sim 10 ^ { 12 } M _ { \odot } ) .
The detection of the [ NII ] emission at 205 \mu m suggests that the metallicity in B0952 is consistent with solar , implying that the chemical evolution has progressed very rapidly in this system .
We also present PdBI observations of the [ CII ] emission line in SDSSJ1148+5251 ( S1148 ) , one of the most distant QSO known , at z=6.4 .
We detect broad wings in the [ CII ] emission line , indicative of gas which is outflowing from the host galaxy .
In particular , the extent of the wings , and the size of the [ CII ] emitting region associated to them , are indicative of a QSO-driven massive outflow with the highest outflow rate ever found ( \dot { M } > 3500 ~ { } M _ { \odot } ~ { } yr ^ { -1 } ) .