Third Interplanetary Network Localization, Time History, Fluence, Peak Flux, and Distance Lower Limit of the 1997 February 28 Gamma-Ray Burst
Frontera, F.; Orlandini, M.; Cline, T.; Hurley, K.; Costa, E.; Boer, M.; Golenetskii, S.; Feroci, M.; Mazets, E.; Dal Fiume, D.; Aptekar, R.; Terekhov, M.
United States, Italy, France, Russia
Abstract
The gamma-ray burst of 1997 February 28 was localized using the arrival time analysis method with the Ulysses, BeppoSAX, and WIND spacecraft. The result is a +/-31.5" (3 σ) wide annulus of possible arrival directions that intersects both the position of the burst determined independently by the BeppoSAX Wide Field Camera and the position of a fading X-ray source detected by the BeppoSAX focusing X-ray telescopes and reduces these source location areas by factors of 7 and 1.5, respectively. The combination of the annulus and the BeppoSAX locations, a 0.76 arcmin square error box, is consistent with that of an optical transient source and an extended object, possibly a galaxy. We also present the time history, peak flux, and fluence of this event, and we derive a model-independent lower limit to the source distance of ~11,000 AU.