The bright GRB 050408 was localized by HETE-2 near local midnight in the Western Hemisphere, enabling an impressive ground-based follow- up effort, as well as space-based follow-up from Swift. The Swift data from the XRT and our own optical …
We report observations of GRB 050525A, for which a Gemini North spectrum shows its redshift to be z=0.606. This is the third closest long GRB discovered by Swift. We observed its afterglow using the VLT, Gemini, and TNG telescopes to search for an …
The rapid succession of discoveries of short-duration hard-spectrum gamma-ray bursts (GRBs) has led to unprecedented insights into the energetics of the explosion and nature of the progenitors. Yet short of the detection of a smoking gun, such as a …
The localization of the short-duration, hard-spectrum gamma-ray burst GRB 050509b by the Swift satellite was a watershed event. We report the discovery of the probable host galaxy, a bright elliptical galaxy at z=0.2248. This is the first known …
We present light curves of the afterglow of GRB 050502A, including very early data at t-t$_GRB$<60 s. The light curve is composed of unfiltered ROTSE-IIIb optical observations from 44 s to 6 hr postburst, R-band MDM observations from 1.6 to 8.4 hr …
The Ultraviolet/Optical Telescope (UVOT) on board Swift has the capability to provide critical insight into the physics of the early afterglows of gamma-ray bursts (GRBs). But without precise calibration of the UVOT to standard photometric systems, …
We present an echelle spectrum of the Swift GRB 050730, obtained 4 hr after the burst using the MIKE spectrograph on the Magellan Clay telescope when the afterglow was at R=17.7. The spectrum reveals a forest of absorption features superposed on a …
The use of gamma-ray burst (GRB) energetics for cosmography has long been advanced as a means to probe out to high redshifts, to the epoch of deceleration. However, although relatively immune to systematic biases from dust extinction, the prompt …
We present BVR$_C$JHK$_s$ photometry of the optical afterglow of the gamma-ray burst GRB 021211 taken at the Magellan, MMT, and WIYN observatories between 0.7 and 50 days after the burst. We find an intrinsic spectral slope at optical and …
We present Keck/NIRSPEC near-IR images and Magellan/IMACS optical spectroscopy of the host galaxy of GRB 031203. The host is an actively star-forming galaxy at z=0.1055+/-0.0001. This is the lowest redshift GRB to date, aside from GRB 980425. From …