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Titolo:
The jet and circumburst stellar wind of GRB 9805191
Autore:
Jaunsen, AO; Hjorth, J; Bjornsson, G; Andersen, MI; Pedersen, H; Kjernsmo, K; Korhonen, H; Sorensen, PM; Palazzi, E;
Indirizzi:
Univ Oslo, Inst Theoret Astrophys, N-0315 Oslo, Norway Univ Oslo Oslo Norway N-0315 Inst Theoret Astrophys, N-0315 Oslo, Norway Ctr Adv Study, N-0271 Oslo, Norway Ctr Adv Study Oslo Norway N-0271Ctr Adv Study, N-0271 Oslo, Norway Univ Copenhagen, Astron Observ, DK-2100 Copenhagen, Denmark Univ Copenhagen Copenhagen Denmark DK-2100 , DK-2100 Copenhagen, Denmark NORDITA, DK-2100 Copenhagen O, Denmark NORDITA Copenhagen Denmark ONORDITA, DK-2100 Copenhagen O, Denmark Univ Iceland, Inst Sci, IS-107 Reykjavik, Iceland Univ Iceland ReykjavikIceland IS-107 nst Sci, IS-107 Reykjavik, Iceland Univ Oulu, Dept Phys Sci, Astron Div, FIN-90014 Oulu, Finland Univ Oulu Oulu Finland FIN-90014 ci, Astron Div, FIN-90014 Oulu, Finland Nord Opt Telescope, E-38700 St Cruz De La Palma, Canarias, Spain Nord Opt Telescope St Cruz De La Palma Canarias Spain E-38700 rias, Spain Isaac Newton Grp, E-38700 Santa Cruz De La Palma, Canarias, Spain Isaac Newton Grp Santa Cruz De La Palma Canarias Spain E-38700 ias, Spain CNR, Inst Tecnol & Studio Radiaz Extraterr, I-40129 Bologna, Italy CNR Bologna Italy I-40129 tudio Radiaz Extraterr, I-40129 Bologna, Italy
Titolo Testata:
ASTROPHYSICAL JOURNAL
fascicolo: 1, volume: 546, anno: 2001,
parte:, 1
pagine: 127 - 133
SICI:
0004-637X(20010101)546:1<127:TJACSW>2.0.ZU;2-9
Fonte:
ISI
Lingua:
ENG
Soggetto:
GAMMA-RAY BURST; AFTERGLOW; SUPERNOVA;
Keywords:
cosmology : miscellaneous; cosmology : observations; dust, extinction; gamma rays : bursts; supernovae : general;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
42
Recensione:
Indirizzi per estratti:
Indirizzo: Jaunsen, AO Univ Oslo, Inst Theoret Astrophys, Pb 1029, N-0315 Oslo, Norway Univ Oslo Pb 1029 Oslo Norway N-0315 029, N-0315 Oslo, Norway
Citazione:
A.O. Jaunsen et al., "The jet and circumburst stellar wind of GRB 9805191", ASTROPHYS J, 546(1), 2001, pp. 127-133

Abstract

We present extensive multicolor (UBVRCIC) photometry of the optical afterglow of GRB 980519. Upon discovery, 8.3 hr after the burst, the source was decaying as a power law, with a rapid (t - t(GRB))(alpha), decay rate alpha (1) = -1.73 +/- 0.04. About 13 hr after the burst a steepening of the lightcurve to alpha (2) = -2.22 +/- 0.04 was observed. Within the framework of current afterglow models, we argue that the rapid initial decline, the "break" in the light curve, and the spectral properties of the afterglow are best interpreted as being due to a collimated ultrarelativistic jet of fixed opening angle expanding into an inhomogeneous medium. In this scenario, we find that the circumburst medium has a density structure that goes as r(-2.05+0.22). This is characteristic of a preexisting wind expelled from a massive star. A possible physical scenario is that the progenitor star collapsed to form a black hole (i.e., a "collapsar"), producing the observed burst and afterglow. However, the supernova signature expected in the light curvein such a scenario is not detected. This either implies that the redshift of GRB 980519 is greater than 1.5 or that supernovae accompanying GRBs are not standard candles.

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Documento generato il 26/09/17 alle ore 09:26:28