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Titolo:
BeppoSAX confirmation of beamed afterglow emission from GRB 990510
Autore:
Pian, E; Soffitta, P; Alessi, A; Amati, L; Costa, E; Frontera, F; Fruchter, A; Masetti, N; Palazzi, E; Panaitescu, A; Kumar, P;
Indirizzi:
Osservatorio Astron Trieste, I-34131 Trieste, Italy Osservatorio Astron Trieste Trieste Italy I-34131 I-34131 Trieste, Italy CNR, Ist Tecnol & Studio Radiaz Extraterr, I-40129 Bologna, Italy CNR Bologna Italy I-40129 tudio Radiaz Extraterr, I-40129 Bologna, Italy CNR, Ist Astrofis Spaziale, Area Ric Tor Vergata, I-00133 Rome, Italy CNRRome Italy I-00133 aziale, Area Ric Tor Vergata, I-00133 Rome, Italy Univ Bologna, Dipartimento Astron, I-40127 Bologna, Italy Univ Bologna Bologna Italy I-40127 imento Astron, I-40127 Bologna, Italy Univ Ferrara, Dipartimento Fis, I-41100 Ferrara, Italy Univ Ferrara Ferrara Italy I-41100 artimento Fis, I-41100 Ferrara, Italy Space Telescope Sci Inst, Baltimore, MD 21218 USA Space Telescope Sci Inst Baltimore MD USA 21218 , Baltimore, MD 21218 USA Princeton Univ, Dept Astrophys Sci, Princeton, NJ 08544 USA Princeton Univ Princeton NJ USA 08544 rophys Sci, Princeton, NJ 08544 USA Inst Adv Study, Princeton, NJ 08540 USA Inst Adv Study Princeton NJ USA 08540 Adv Study, Princeton, NJ 08540 USA
Titolo Testata:
ASTRONOMY & ASTROPHYSICS
fascicolo: 2, volume: 372, anno: 2001,
pagine: 456 - 462
SICI:
1432-0746(200106)372:2<456:BCOBAE>2.0.ZU;2-6
Fonte:
ISI
Lingua:
ENG
Soggetto:
X-RAY AFTERGLOW; GRB-990510; BURSTS; ESO;
Keywords:
gamma rays : bursts; X-rays : general; radiation mechanisms : non-thermal;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
33
Recensione:
Indirizzi per estratti:
Indirizzo: Pian, E Osservatorio Astron Trieste, Via GB Tiepolo 11, I-34131 Trieste, Italy Osservatorio Astron Trieste Via GB Tiepolo 11 Trieste Italy I-34131
Citazione:
E. Pian et al., "BeppoSAX confirmation of beamed afterglow emission from GRB 990510", ASTRON ASTR, 372(2), 2001, pp. 456-462

Abstract

We compare the prompt X-ray (2-10 keV) emission of GRB 990510 measured by the BeppoSAX Wide Field Cameras (WFC) during the burst to the X-ray afterglow detected by the BeppoSAX Narrow Field Instruments. A single power-law model for the afterglow, f(t) proportional to t(-1.42), is ruled out. Provided the initial time of the afterglow is assumed to coincide with the last short pulse in the X-ray prompt event (i.e., 72 s after the GRB trigger time), the X-ray emission from similar to 80 to 10(5) s after the GRB trigger iswell described by an external shock expanding in a decelerating jet, in which synchrotron radiation takes place. This model, represented by a double power-law of indices alpha (1) similar or equal to 1 and alpha (2) similar or equal to 2 before and after a jet collimation break time of similar to0.5 days after GRB, respectively, is consistent with the second and third upper limits measured by the WFC, but not with the first. This may be related to inhomogeneities in the circumburst medium. Our finding indicates that the temporal behavior of the GRB 990510 X-ray afterglow is similar to that atoptical wavelengths, and thus strengthens the interpretation of the multiwavelength afterglow as synchrotron emission in a jet with decreasing Lorentz factor. GRB 990510 is thus the only burst in which evidence of a spreading jet has been found in X-rays.

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Documento generato il 18/11/17 alle ore 03:48:40