With this paper we want to investigate the highly variable afterglow light curve and environment of gamma-ray burst ( GRB ) 060526 at z = 3.221 .
We present one of the largest photometric datasets ever obtained for a GRB afterglow , consisting of multi-color photometric data from the ultraviolet to the near infrared .
The data set contains 412 data points in total to which we add additional data from the literature .
Furthermore , we present low-resolution high signal-to-noise spectra of the afterglow .
The afterglow light curve is modeled with both an analytical model using broken power law fits and with a broad-band numerical model which includes energy injections .
The absorption lines detected in the spectra are used to derive column densities using a multi-ion single-component curve-of-growth analysis from which we derive the metallicity of the host of GRB 060526 .
The temporal behaviour of the afterglow follows a double broken power law with breaks at t = 0.090 \pm 0.005 and t = 2.401 \pm 0.061 days .
It shows deviations from the smooth set of power laws that can be modeled by additional energy injections from the central engine , although some significant microvariability remains .
The broadband spectral-energy distribution of the afterglow shows no significant extinction along the line of sight .
The metallicity derived from S II and Fe II of [ S/H ] = –0.57 \pm 0.25 and [ Fe/H ] = –1.09 \pm 0.24 is relatively high for a galaxy at that redshift but comparable to the metallicity of other GRB hosts at similar redshifts .
At the position of the afterglow , no host is detected to F775W ( AB ) = 28.5 mag with the HST , implying an absolute magnitude of the host M ( 1500 Ã ) > –18.3 mag which is fainter than most long-duration hosts , although the GRB may be associated with a faint galaxy at a distance of 11 kpc .