High-resolution spectroscopy of gamma-ray bursts with the transient gamma-ray spectrometer

A search for spectral lines in gamma-ray bursts detected with the Transient Gamma-Ray Spectrometer has been unable to confirm their existence. The spe ctrometer, aboard the Wind spacecraft, has detected gamma-ray bursts and ot her transients since 1995. We have performed a systematic search for narrow spectral lines in gamma-ray bursts detected with this instrument that augm ents and extends the results of a similar search of bursts detected with BA TSE. This search procedure tests for statistically significant lines at all possible times and durations during a burst using the method of maximum li kelihood and C-statistic. Simulations demonstrated the effectiveness of thi s procedure, particularly on Poisson distributed data, for distinguishing r eal features from statistical fluctuations. The most promising line candida tes were consistent with chance fluctuations, given the large number of spe ctra searched.