WFC Science highlights - Gamma-ray burst 980519
GRB 980519 is the second brightest X-ray counterpart to a GRB measured
by WFC. The richness in the data has enabled a more-than-usual thorough
study of the X-ray emission of the burst. The X-ray emission is very
interesting because it seems to start before the gamma-rays.
Photon count rates in a number of X-ray and gamma-ray bandpasses,
using WFC and BATSE data. There is clearly X-ray activity before
the gamma-ray event sets in
A detailed analysis of the X-ray spectral evolution, however, shows that
the precursor X-ray emission is rather common to that during the
gamma-ray phase and to the X-ray spectra of other GRBs. Therefore, this
burst is probably nothing more than a rare (though not unprecedented)
example of a soft-to-hard-to-soft evolution.
These results have been published by Jean in 't Zand, John Heise,
Jan van Paradijs and Ed Fenimore (ApJL 1999,
in press)
Jean in 't Zand, SRON, March 12, 1999