Discovery of an X-ray afterglow associated with the γ-ray burst of 28 February 1997

• DOI: 10.1038/42885
• Publication Date: 2002-07-26T08:35:11Z
• Authors: E. Costa; F. Frontera; J. Heise; M. Feroci; J. in 't Zand; F. Fiore; M. N. Cinti; D. Dal Fiume; L. Nicastro; M. Orlandini; E. Palazzi; M. Rapisarda#; G. Zavattini; R. Jager; A. Parmar; A. Owens; S. Molendi; G. Cusumano; M. C. Maccarone; S. Giarrusso; A. Coletta; L. A. Antonelli; P. Giommi; J. M. Muller; L. Piro; R. C. Butler
• Keywords: Astrophysics (astro-ph); 0103 physical sciences; FOS: Physical sciences; Astrophysics; 01 natural sciences

10 pages, LaTeX, 3 postscript figures; Nature, issue of 19 June 1997<br/>Here we report the discovery in the X-ray band of the first afterglow of a gamma-ray burst. It was detected and quickly positioned by the Beppo-SAX satellite on 1997 February 28 (GRB970228). The X-ray afterglow source was detected with the X-ray telescopes aboard the same satellite about eight hours after the burst and faded away in a few days with a power law decay function. The energetic content of the X-ray afterglow results to be a significant fraction of gamma-ray burst energetics. The Beppo-SAX detection and fast imaging of GRB970228 started a multiwavelength campaign that lead to the identification of a fading optical source in a position consistent with the X-ray source.<br/>