Author: Antonino Cucchiara
Abstract: GRBs are incredible tools to study the early Universe. In particular, using GRB afterglows spectroscopy we can investigate the chemical enrichment throughout the cosmic time in a unique way: absorption lines detected in these data often probe the inner regions of the GRB hosts as well as the deep sectrets of the GRB progenitors birth-sites. The detection of neutral hydrogen (NHI), low and hogh-ionized metal species shows a complex, diversified set of environemnts. We present the largest compilation of absorption lines Equivalent Widths to date, including data from our Gemini follow-up campaigns (obtained over 6 year, covering ∼40% of the GRB afterglows spectroscopic redshift obtained to date) as well as data from the literature. With this dataset we present results on metallicity evolution, alpha-element enhancement and dust content within the GRB host galaxies, along the specific line of sight that probes, better than host galaxy integrated-light spectroscopy, the inner parts of the GRBs star-forming regions.