We report new imaging and spectroscopic observations of the damped Ly \alpha ( DLA ) galaxy SBS 1543+593 , a nearby dwarf galaxy whose stellar disk is intersected by the sightline to the bright background QSO HS 1543+5921 . Hubble Space Telescope imaging observations with WFPC2 in the F450W and F702W bands are used to measure the DLA galaxy ’ s properties and compile a catalog of its ( candidate ) H ii regions .
Ground-based long-slit spectroscopy of the brightest H ii region in the galaxy yields estimates of the star formation rate ( SFR ) and of chemical abundances in the galaxy ’ s interstellar medium .
We find that SBS 1543+593 exhibits a SFR \approx 0.006 h ^ { -2 } _ { 70 } M _ { \odot } yr ^ { -1 } , or a SFR per unit area of \approx~ { } 1.4 \times 10 ^ { -4 } h ^ { -2 } _ { 70 } M _ { \odot } yr ^ { -1 } kpc ^ { -2 } .
We derive gas-phase abundances in the ionized gas of 12 + \log { ( O / H ) } = 8.2 \pm 0.2 , which is about 1/3 of the solar value , and \log { ( N / O ) } = -1.40 ^ { +0.2 } _ { -0.3 } .
These values are consistent with the morphologial appearance of SBS 1543+593 , an Sm dwarf of M _ { B } -5 \log h _ { 70 } = -16.8 \pm 0.2 
and of intermediate surface brightness .
SBS 1543+593 is the first bona fide DLA for which abundances have been measured using emission-line diagnostics .
When compared with future , high-resolution , ultraviolet spectroscopy , our results should prove key for interpreting abundance determinations in high redshift DLAs .