Galaxies: Abundances

Progenitor Diagnostics for Stripped Core-collapse Supernovae: Measured Metallicities at Explosion Sites

Metallicity is expected to influence not only the lives of massive stars but also the outcome of their deaths as supernovae (SNe) and gamma-ray bursts (GRBs). However, there are surprisingly few direct measurements of the local metallicities of …

Time-dependent Optical Spectroscopy of GRB 010222: Clues to the Gamma-Ray Burst Environment

We present sequential optical spectra of the afterglow of GRB 010222 obtained 1 day apart using the Low-Resolution Imaging Spectrometer (LRIS) and the Echellette Spectrograph and Imager (ESI) on the Keck Telescopes. Three low-ionization absorption …