GRB 011211 was detected by the Italian–DutchX-ray astronomy satelliteBeppoSAX on 11 December 2001 at 19:09UTC.[2] The burst lasted 270 seconds, making it the longest burst that had ever been detected by BeppoSAX up to that point.[3] Aspectrum recorded by theYepun telescope indicated aredshift of z = 2.14.[4]
A team of researchers at theUniversity of Leicester conducted an analysis of the burst's X-ray afterglow with theXMM-Newton observatory. They found evidence foremission lines of magnesium, silicon, sulphur, and various otherchemical elements. This was the first detection of these elements in the spectrum of a GRB.[5] These observations provided strong evidence for a relation between gamma-ray bursts andsupernova.[3] However, other astronomers pointed out flaws in the methodology of the Leicester research team, such as thedata reduction methods,[6] the lowstatistical significance of the emission lines,[7] and the lowspectral resolution of the instrument used.[8] Despite a follow-up paper from the Leicester team to address these concerns,[9] the findings remained controversial, andGRB 020813 was given the distinction of being the first burst with direct evidence of a supernova relation.[10][11]
Optical, infrared, and X-ray observations taken by theHubble Space Telescope between 14 and 59 days after the burst's detection revealed a blue galaxy with anapparent magnitude of 24.95 ± 0.11.[12] Like several other gamma-ray burst hosts,Lyman alpha emission was detected from this galaxy, supporting the theory that theprogenitors of gamma-ray burst tend to be metal-poor.[13]
