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تسجيل مستخدم جديدObservation of X-ray lines from a Gamma-Ray Burst (GRB991216): Evidence of Moving Ejecta from the Progenitor
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We report on the discovery of two emission features observed in the X-ray spectrum of the afterglow of the gamma-ray burst (GRB) of 16 Dec. 1999 by the Chandra X-Ray Observatory. These features are identified with the Ly$_{alpha}$ line and the narrow recombination continuum by hydrogenic ions of iron at a redshift $z=1.00pm0.02$, providing an unambiguous measurement of the distance of a GRB. Line width and intensity imply that the progenitor of the GRB was a massive star system that ejected, before the GRB event, $approx 0.01 Ms$ of iron at a velocity $approx 0.1 c$, probably by a supernova explosion.
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