A nearby GRB host galaxy: VLT/X-shooter observations of HG 031203
  (abridged) Long-duration gamma-ray bursts (LGRBs) occur in galaxies of
generally low metallicity. We aim at a spectroscopic analysis of HG 031203, the
host galaxy of a LRGB burst, to obtain its properties. Based on VLT/X-shooter
spectroscopic observations in the wavelength range 3200-24000A, we use standard
direct methods to evaluate physical conditions and element abundances. The
resolving power of the instrument also allowed us to trace the kinematics of
the ionised gas. We derive an interstellar oxygen abundance of
12+logO/H=8.20+/-0.03. The observed fluxes of hydrogen lines correspond to the
theoretical recombination values after correction for extinction with a single
value C(Hbeta)=1.67. We produce the CLOUDY photoionisation HII region model
that reproduces observed emission-line fluxes of different ions in the optical
range. This model also predicts emission-line fluxes in the near-infrared (NIR)
and mid-infrared (MIR) ranges that agree well with the observed ones. This
implies that the star-forming region observed in the optical range is the only
source of ionisation and there is no additional source of ionisation seen in
the NIR and MIR ranges that is hidden in the optical range.We find that the
heavy element abundances, Halpha luminosity, stellar mass, star-formation rate
and specific star-formation rate of HG 031203 are in the range that is covered
by the luminous compact galaxies (LCGs).This implies that the LCGs with extreme
star-formation that also comprise green pea galaxies as a subclass may harbour
LGRBs.
