标题： GRB970402的BeppoSAX观测 显示英文标题

标题： BeppoSAX observations of GRB970402

摘要： GRB970402是BeppoSAX在伽马射线暴监测器（GRBM）和两个宽视场相机（WFCs）中的一个同时检测到的第四次伽马射线暴。 在GRB发生8小时后，对BeppoSAX窄视场仪器（NFIs）的快速指向导致识别出一个未知的弱X射线源：1SAX J1450.1-6920。 它的位置大约位于从WFC图像得出的3角分误差圆的中心。 中能（MECS，2-10 keV）和低能（LECS，0.1-10 keV）聚焦器都探测到了该源。 在1.5天后进行的后续观测持续了54 ks，结果显示该源几乎降至但未低于可探测阈值。 两次观测之间的通量减少了一个约2.5倍的因子。 1SAX J1450.1-6920是与GRB相关的第二个X射线余辉。 在其他波长（光学、红外、射电）迅速展开的搜索并未在3角分误差圆内发现任何瞬变事件。 显示英文摘要

摘要： GRB970402 is the fourth gamma-ray burst detected by BeppoSAX simultaneously in the Gamma Ray Burst Monitor (GRBM) and one of the two Wide Field Cameras (WFCs). A rapid pointing of the BeppoSAX Narrow Field Instruments (NFIs) 8 hours after the GRB led to the identification of an unknown weak X-ray source: 1SAX J1450.1-6920. Its position was approximately at the center of the 3 arcmin error circle derived from the WFC image. Both the Medium Energy (MECS, 2-10 keV) and Low Energy (LECS, 0.1-10 keV) concentrators detected the source. A follow-up observation performed 1.5 days later and lasting 54 ks showed that the source had faded almost to, but not below the detectability threshold. The flux decrease between the two observations was a factor ~= 2.5. 1SAX J1450.1-6920 was the second X-ray afterglow associated with a GRB. Searches promptly started at other wavelengths (optical, IR, radio) did not reveal any transient event within the 3 arcmin error circle.