The host of the SN-less GRB 060505 in high resolution
  The spiral host galaxy of GRB 060505 at z=0.089 was the site of a puzzling
long duration burst without an accompanying supernova. Studies of the burst
environment by Th\"one et al. (2008) suggested that this GRB came from the
collapse of a massive star and that the GRB site was a region with properties
different from the rest of the galaxy. We reobserved the galaxy in high spatial
resolution using the VIMOS integral-field unit (IFU) at the VLT with a spaxel
size of 0.67 arcsec. Furthermore, we use long slit high resolution data from
HIRES/Keck at two different slit positions covering the GRB site, the center of
the galaxy and an HII region next to the GRB region. We compare the properties
of different HII regions in the galaxy with the GRB site and study the global
and local kinematic properties of this galaxy. The resolved data show that the
GRB site has the lowest metallicity in the galaxy with around 1/3 Z_solar, but
its specific SFR (SSFR) of 7.4 M_solar/yr/L/L* and age (determined by the
Halpha EW) are similar to other HII regions in the host. The galaxy shows a
gradient in metallicity and SSFR from the bulge to the outskirts as it is
common for spiral galaxies. This gives further support to the theory that GRBs
prefer regions of higher star-formation and lower metallicity, which, in S-type
galaxies, are more easily found in the spiral arms than in the centre.
Kinematic measurements of the galaxy do not show evidence for large
perturbations but a minor merger in the past cannot be excluded. This study
confirms the collapsar origin of GRB060505 but reveals that the properties of
the HII region surrounding the GRB were not unique to that galaxy. Spatially
resolved observations are key to know the implications and interpretations of
unresolved GRB hosts observations at higher redshifts.
