Details

Autor(en) / Beteiligte

• Amati, Lorenzo
• Frontera, Filippo
• Vietri, Mario
• Jean J. M. in 't Zand
• Soffitta, Paolo
• Costa, Enrico
• Del Sordo, Stefano
• Pian, Elena
• Piro, Luigi
• Antonelli, Lucio A.
• Fiume, D. Dal
• Feroci, Marco
• Gandolfi, Giangiacomo
• Guidorzi, Cristiano
• Heise, John
• Kuulkers, Erik
• Masetti, Nicola
• Montanari, Enrico
• Nicastro, Luciano
• Orlandini, Mauro
• Palazzi, Eliana

Titel

Discovery of a Transient Absorption Edge in the X-ray Spectrum of GRB 990705

Ist Teil von

• Science (American Association for the Advancement of Science), 2000-11, Vol.290 (5493), p.953-955

Ort / Verlag

Washington, DC: American Society for the Advancement of Science

Erscheinungsjahr

2000

Quelle

Science Online

Beschreibungen/Notizen

• We report the discovery of a transient equivalent hydrogen column density with an absorption edge at ∼3.8 kiloelectron volts in the spectrum of the prompt x-ray emission of gamma-ray burst (GRB) 990705. This feature can be satisfactorily modeled with a photoelectric absorption by a medium located at a redshift of ∼0.86 and with an iron abundance of ∼75 times the solar one. The transient behavior is attributed to the strong ionization produced in the circumburst medium by the GRB photons. The high iron abundance points to the existence of a burst environment enriched by a supernova along the line of sight. The supernova explosion is estimated to have occurred about 10 years before the burst. Our results agree with models in which GRBs originate from the collapse of very massive stars and are preceded by a supernova event.