Discovery of a Redshifted Iron K Line in the X-Ray Afterglow of GRB 000214
Antonelli, L. A. LA ; Piro, L. ; Vietri, M. ; et al. ; - ASI Sponsor
Dec - 2000
ISSN : 0004637X ;
journal : The Astrophysical Journal

Issue : 1
type: Article Journal

Abstract
We report the detection (3 \sigma significance level) of a strong iron emission line in the X-ray spectrum of the afterglow of GRB 000214 (Valentines Day Burst) observed by BeppoSAX . An emission-line feature was observed with a centroid energy of 4.7 ± 0.2 keV, which, if interpreted as K\alpha emission from hydrogen-like iron, corresponds to a redshift of z = 0.47. The intensity (EW 2 keV) and duration (tens of hours) of the line give information on the distance, from the burst region, of the emitting material ( R ≥ 3 × 10 15 cm) and its mass ( M ≥ 1.4 M ☉ ). These results are not easily reconciled with the binary merger and hypernova models for gamma-ray bursts because they require large amounts of mass (about 1 M ☉ ) at large distances (≈10 16 cm) and at Newtonian speeds.

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