标题： VERITAS对Swift探测到的伽马射线暴的观测 显示英文标题

标题： VERITAS Observations of Gamma-Ray Bursts Detected by Swift

摘要： 我们展示了使用VERITAS望远镜阵列在2007年1月至2009年6月期间对16次Swift触发的伽玛射线暴进行后续观测的结果。这些观测的中位能量阈值和响应时间分别为260 GeV和320秒。观测的平均持续时间为90分钟。每个爆发分别在两种模式下进行分析：一种是整个观测持续时间，另一种是根据VERITAS对具有t^-1.5时间轮廓的爆发的最大灵敏度确定的较短时间尺度。这种时间模型是高能、寿命长的伽玛射线暴余辉的特征，这些余辉已被费米卫星上的大面积望远镜（LAT）探测到。没有检测到显著的超高能伽玛射线辐射，并计算了高于VERITAS阈值能量的上限。VERITAS的上限考虑了宇宙背景光对伽玛射线的消光效应，并结合Swift探测到的keV辐射进行解释。对于某些爆发，超高能辐射的功率必须低于keV辐射，这为超高能辐射的逆康普顿模型提供了约束。 显示英文摘要

摘要： We present the results of sixteen Swift-triggered GRB follow-up observations taken with the VERITAS telescope array from January, 2007 to June, 2009. The median energy threshold and response time of these observations was 260 GeV and 320 s, respectively. Observations had an average duration of 90 minutes. Each burst is analyzed independently in two modes: over the whole duration of the observations and again over a shorter time scale determined by the maximum VERITAS sensitivity to a burst with a t^-1.5 time profile. This temporal model is characteristic of GRB afterglows with high-energy, long-lived emission that have been detected by the Large Area Telescope (LAT) on-board the Fermi satellite. No significant VHE gamma-ray emission was detected and upper limits above the VERITAS threshold energy are calculated. The VERITAS upper limits are corrected for gamma-ray extinction by the extragalactic background light (EBL) and interpreted in the context of the keV emission detected by Swift. For some bursts the VHE emission must have less power than the keV emission, placing constraints on inverse Compton models of VHE emission.