Fermi Gamma-ray Space Telescope

Studies of Fermi GRB Host Galaxies via Optical Afterglow Spectroscopy

S. Hales
S. McBreen

Abstract:

Gamma-ray bursts (GRBs) are short-lived and unpredictable events which are detected about once per day in the observable universe. The GRB explosion produces a fireball and a blast-wave which is ejected into the interstellar medium of the host galaxy. The resulting afterglow radiates at X-ray, optical, infrared, and radio wavelengths in the days and weeks after the burst. In the case of faint galaxies the GRB afterglow facilitates absorption spectroscopy of the host using large telescopes such as the VLTs. This spectroscopic analysis can reveal complex absorption systems and, in some cases, determine the metal abundances of these galaxies. We present the various methodologies that have been used in the reduction and analysis of optical spectroscopy and explore the procedures involved in the determination of the environment within the host galaxy. The research into the composition of GRB host galaxies using optical spectroscopy forms the bases of my reseach MSc at University College Dublin.