A SUPER-DAMPED Ly alpha QUASI-S℡LAR OBJECT ABSORBER AT z=2.2

International audienceWe report the discovery of a “super-damped” Ly alpha absorber at z(abs) = 2.2068 toward quasi-stellar object (QSO) Q1135-0010 in the Sloan Digital Sky Survey (SDSS) and follow-up Very Large Telescope (VLT) UVES spectroscopy. A Voigt profile fit to the damped Ly alpha (DLA) line indicates log N-HI = 22.05 +/- 0.1. This is the second QSO DLA discovered to date with such high N-HI. We derive element abundances [Si/H]=-1.10 +/- 0.10, [Zn/H] = -1.06 +/- 0.10, [Cr/H] = -1.55 +/- 0.10, [Ni/H] = -1.60 +/- 0.10, [Fe/H] = -1.76 +/- 0.10, [Ti/H] = -1.69 +/- 0.11, [P/H] = -0.93 +/- 0.23, and [Cu/H] = -0.75 +/- 0.14. Our data indicate detection of Ly alpha emission in the DLA trough, implying a star formation rate (SFR) of similar to 10 M-circle dot yr(-1) in the absence of dust attenuation. C II* lambda 1336 absorption is also detected, suggesting SFR surface density -2 \textless log (psi) over dot(*) \textless 0 M-circle dot yr(-1) kpc(-2). We estimate electron density in the range 3.5 x 10(-4) to 24.7 cm (3) from C II*/C II and similar to 0.5-0.9 cm (3) from Si II*/Si II. Overall, this is a robustly star-forming, moderately enriched absorber, but with relatively low dust depletion. Fitting of the SDSS spectrum yields low reddening for Milky Way, Large Magellanic Cloud, or Small Magellanic Cloud (SMC) extinction curves. No CO absorption is detected, and C I absorption is weak. The low dust and molecular content, reminiscent of some SMC sight lines, may result from the lower metallicity and a stronger radiation field (due to higher SFR). Finally, we compare this absorber with other QSO and gamma-ray burst DLAs