Program: GS-2007B-Q-2

The Swift satellite has revolutionized the study of gamma-ray bursts by providing unprecedented numbers of accurate real-time localizations. A pressing question -- which we hope to address with a systematic imaging study with Gemini -- is the origin of so-called dark afterglow GRBs, which comprise roughly half the existing sample. Constraining, in particular, the number of dark GRBs at high redshift (z > 6) has important implications for understanding the bursts themselves as well as informing the role of future missions (eg. JDEM, EXIST). In general, GRB afterglows have proven to be a versatile and unique astrophysical probe in the study of the ISM of distant galaxies, the IGM at z>2, and into the reionization epoch. To this end, our proposed semester 2007B ToO program also seeks to uncover a number of damped-Lyman alpha systems as well as improve the (troublesome) statistics of strong intervening Mg II absorbers towards GRB sitelines.