Gamma-ray burst host galaxies in absorption

Long duration gamma-ray bursts (GRBs) are caused by the deaths of massive stars, and can be seen to extremely large distances. By observing the imprint of foreground material on the featureless GRB spectra, it is possible to study their host galaxies in order to gain an understanding of the conditions at high redshift. In this thesis, spectral data is used to investigate the dust properties of 19 GRB hosts. The results indicate that significant amounts of dust must be formed by grain growth rather than in stars and supernovae. Furthermore, the remarkable host of GRB 080810 is investigated, revealing both inflowing and outflowing gas in unprecedented detail.