We report the discovery of Serenity-18 , a galaxy at z \simeq 5.939 for which we could measure the content of molecular gas , M ( { H } _ { 2 } ) \simeq 5 \times 10 ^ { 9 } M _ { \sun } , traced by the CO ( 6-5 ) emission , together with the metal poor ( [ Fe/H ] = -3.08 \pm 0.12 , [ Si/H ] = -2.86 \pm 0.14 ) gas clump/filament which is possibly feeding its growth .
The galaxy has an estimated star formation rate of \approx 100 M _ { \sun } yr ^ { -1 } , implying that it is a typical main sequence galaxy at these redshifts .
The metal poor gas is detected through a damped Lyman- \alpha absorber ( DLA ) observed at a spatial separation of 40 kpc and at the same redshift of Serenity-18 , along the line of sight to the quasar SDSS J2310+1855 ( z _ { em } \simeq 6.0025 ) .
The chemical abundances measured for the damped Lyman- \alpha system are in very good agreement with those measured for other DLAs discovered at similar redshifts , indicating an enrichment due to massive PopII stars .
The galaxy/damped system that we discovered is a direct observational evidence of the assembly of a galaxy at the edge of the reionization epoch .