| Abstract
| - We present the first high-resolution (6.2 to 7.7 km s -1FWHM) spectra of the APM BR J0307-4945 quasar at $z_{\rm em} = 4.73$ obtained with UVES on the 8.2 m VLT Kueyen telescope. We focus our analysis on a damped Ly α (DLA) system at $z_{\rm abs} = 4.466$ with a neutral hydrogen column density N(H i) $= (4.68 \pm 0.97) 10^{20}$ cm -2. It is the most distant DLA system known to the present date, observed when the age of the universe was only 1.3 Gyr. It shows complex low- and high-ionization line profiles spanning ≈240 and 300 km s -1 in velocity space respectively. We derive accurate abundances for N, O, Al, Si and Fe, and place a lower limit on C and an upper limit on Ni: [N/H] $=-3.07\pm 0.15$, [O/H] $=-1.63\pm 0.19$, [Al/H] $=-1.79\pm 0.11$, [Si/H] $=-1.54\pm 0.11$, [Fe/H] $=-1.97\pm 0.19$, [C/H] $> -1.63$ and [Ni/H] $< -2.35$. The derived high metallicity, ~1/90 solar, shows that this very young absorber ( ≤1.3 Gyr) has already experienced a significant metal enrichment. The [O/Si] ratio is nearly solar suggesting a limited amount of dust, the relative [Si, O/Fe] abundance ratios show a similar enhancement as observed in the Milky Way stars with comparable metallicities, and the [N/O] ratio is very low. All these results point to an enrichment pattern dominated by type II supernovae which suggests a Milky Way type evolutionary model.
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