Date of Award


Document Type


Degree Name

Master of Science (MS)

Legacy Department



Hartmann, Dr. Dieter H.

Committee Member

King , Dr. Jeremy R.

Committee Member

Leising , Dr. Mark D,

Committee Member

Brittain , Dr. Sean D.


Although long-duration GRBs (LGRBs) are highly transient in nature, their early afterglow can in principle be detected to very high redshifts (Lamb & Reichart, 2000). This makes them potent probes of the chemical evolution and content of the high-redshift universe. In this work, we use photoelectric absorption observed in the XRT spectra of LGRBs to investigate the evolution of metallicities and hydrogen column densities of LGRB host galaxies. Using a high-quality sample of LGRBs indicates the presence of a weak anti-correlation between the abundances and redshift. We also find an evolution trend in intrinsic column density. To confirm these correlations, more high S/N XRT spectra are needed.