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GRB990510: on the possibility of a beamed X-ray afterglow

E. Kuulkers·L. A. Antonelli·L. Kuiper·J. S. Kaastra·L. Amati·E. Costa·F. Frontera·J. Heise·J. J. M. in 't Zand·N. Masetti·L. Nicastro·E. Pian·L. Piro·P. Soffita
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Abstract

We discuss the prompt emission of the gamma-ray burst (GRB) 990510 and its subsequent X-ray afterglow from 8.0 to 44.3 hrs after the prompt emission, using observations with the Gamma-ray Burst Monitor and Narrow Field Instruments on BeppoSAX. In the 40-700 keV band, GRB990510 had a fluence of \~1.9x10^{-5}erg cm^{-2}, whereas it reached a peak flux of ~2.4x10^{-6}erg cm^{-2} s^{-1}. The X-ray afterglow decay light curve can be satisfactorily described by a single power law with index of -1.42+/-0.07. Both the X-ray and optical behaviour of the afterglow can be explained by gamma-ray burst debris expanding as a jet; we find that the cooling frequency is (fixed) between the optical and X-ray wavelength bands.

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E. Kuulkers, L. A. Antonelli, L. Kuiper, J. S. Kaastra, L. Amati, E. Costa, F. Frontera, J. Heise, J. J. M. in 't Zand, N. Masetti, L. Nicastro, E. Pian, L. Piro, P. Soffita. 2000-03-17. GRB990510: on the possibility of a beamed X-ray afterglow. https://doi.org/10.1086/309159

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