We report the detection of a Broad Absorption Line ( BAL ) outflow in the spectrum of the z _ { em } ( Mg ii ) = 2.201 QSO Tol 1037 - 2703 with three main BALs at 36000 , 25300 and 22300 km s ^ { -1 } outflow velocities .
Although the overall flow is dominated by high ionization lines like N v and C iv , the gas of highest velocity shows absorption from Mg i , Mg ii and Fe ii .
Covering factor arguments suggest that the absorbing complexes are physically associated with the QSO and have transverse dimensions smaller than that of the UV continuum emitting region ( r < 0.1 pc ) .
We show that the C iv absorption at z _ { abs } = 2.082 has a covering factor f _ { c } \sim 0.86 and the absorption profile has varied over the last four years .
The detection of absorption from excited fine structure levels of C ii and Si ii in narrow components embedded in the C iv trough reveals large density inhomogeneities .
IR pumping is the most likely excitation process .
The z _ { abs } = 2.139 system is a moderately damped Lyman- \alpha system with log N ( H i ) \sim 19.7 .
The weakness of the metal lines together with the high quality of the data make the metallicity measurements particularly reliable .
The absolute metallicity is close to solar with [ Zn/H ] = - 0.26 .
The \alpha -chain elements have metallicities consistently solar ( respectively +0.05 , - 0.02 , - 0.03 and - 0.15 for [ Mg/H ] , [ Si/H ] , [ P/H ] and [ S/H ] ) and iron peak elements are depleted by a factor of about two ( [ Fe/Zn ] , [ Cr/Zn ] , [ Mn/Zn ] and [ Ni/Zn ] are equal to - 0.39 , - 0.27 , - 0.49 , - 0.30 ) .
Lines from C i are detected but H _ { 2 } is absent with a molecular to neutral hydrogen fraction less than 8 \times 10 ^ { -6 } .
From the ionization state of the gas , we argue that the system is situated \sim few Mpc away from the QSO .
High metallicity and low nitrogen abundance , [ N/Zn ] = - 1.40 , favor the idea that metals have been released by massive stars during a starburst of less than 0.5 Gyr of age .
Using the upper limit on the C i ^ { * } column density in two components , we obtain upper limits on the background temperature of 16.2 and 13.2 K respectively .