Akademik Veri Yönetim Sistemi
ARXIV.ORG, ss.1-10, 2013 (Hakemli Dergi)
Context. Events such as GRB 130606A at z = 5.91, offer an exciting new window into pre-galactic metal enrichment in these very
high redshift host galaxies.
Aims. We study the environment and host galaxy of GRB 130606A, a high-z event, in the context of a high redshift population of
GRBs.
Methods. We have obtained multiwavelength observations from radio to gamma-ray, concentrating particularly on the X-ray evolution
as well as the optical photometric and spectroscopic data analysis.
Results. With an initial Lorentz bulk factor in the range Γ0 ∼ 65-220, the X-ray afterglow evolution can be explained by a timedependent photoionization of the local circumburst medium, within a compact and dense environment. The host galaxy is a sub-DLA
(log N (H I) = 19.85 ± 0.15), with a metallicity content in the range from ∼1/7 to ∼1/60 of solar. Highly ionized species (N V and Si
IV) are also detected.
Conclusions. This is the second highest redshift burst with a measured GRB-DLA metallicity and only the third GRB absorber with
sub-DLA HI column density. GRB ’ lighthouses’ therefore offer enormous potential as backlighting sources to probe the ionization
and metal enrichment state of the IGM at very high redshifts for the chemical signature of the first generation of stars.