Observation of X-ray lines from a gamma-ray burst (GRB991216): evidence of moving ejecta from the progenitor.
/ Authors
L. Piro, G. Garmire, Michael R. Garcia, G. Stratta, E. Costa, M. Feroci, P. Mészáros, M. Vietri, H. Bradt, D. Frail
and 11 more authors
F. Frontera, J. Halpern, J. Heise, K. Hurley, Nobuyuki Kawai, R. Kippen, F. Marshall, T. Murakami, V. Sokolov, T. Takeshima, A. Yoshida
/ Abstract
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 December 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 = 1.00 +/- 0.02, 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, a quantity of iron approximately 0.01 of the mass of the sun at a velocity approximately 0.1 of the speed of light, probably by a supernova explosion.
Journal: Science