Astrophysicists have been studying gamma-ray bursts (GRBs) for more than 30 years, but they still don’t fully understand the cataclysmic cosmic processes that give rise to these brief showers of energetic gamma rays. 1 One technique for learning about the explosions (see also Physics Today 0031-9228 55 7 2002 24 https://doi.org/10.1063/1.1506742 page 24 in this issue) is to study the emissions of the x-ray, optical, or radio afterglows that follow the GRBs: Afterglows can reveal details of the temperature, ionization, composition, and other features of the material illuminated by the bursts.
This past April, James Reeves and colleagues at the University of Leicester, UK, presented an unusually detailed emission spectrum 2 of the x-ray afterglow following the gamma-ray burst GRB011211, so named because it was observed on 11 December 2001. The paper has generated a lot of questions, according to Reeves, with scientists puzzling over how to reconcile the data...
