2001A&A...372..456P


C.D.S. - SIMBAD4 rel 1.7 - 2020.08.04CEST00:07:44

2001A&A...372..456P - Astronomy and Astrophysics, volume 372, 456-462 (2001/6-3)

BeppoSAX confirmation of beamed afterglow emission from GRB 990510.

PIAN E., SOFFITTA P., ALESSI A., AMATI L., COSTA E., FRONTERA F., FRUCHTER A., MASETTI N., PALAZZI E., PANAITESCU A. and KUMAR P.

Abstract (from CDS):

We compare the prompt X-ray (2-10keV) 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)∝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., 72s after the GRB trigger time), the X-ray emission from ∼80 to 105 s after the GRB trigger is well 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 α1≃1 and α2≃2 before and after a jet collimation break time of ∼0.5 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 at optical 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.

Abstract Copyright:

Journal keyword(s): gamma rays: bursts - X-rays: general - radiation mechanisms: non-thermal

Simbad objects: 6

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Number of rows : 6

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 GRB 970228 gB 05 01 46.7 +11 46 53           ~ 626 1
2 GRB 980923 gB 05 07.8 -80 36           ~ 47 0
3 GRB 910402 gB 05 10.5 +13 41           ~ 17 0
4 GRB 990510 gB 13 38 07.64 -80 29 48.8           ~ 465 1
5 GRB 920723 gB 19 10 32 +27 17.8           ~ 42 0
6 GRB 981226 gB 23 29 37.2 -23 55 54           ~ 100 1

    Equat.    Gal    SGal    Ecl

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2020.08.04-00:07:44

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