X射线耀发:γ射线暴中心引擎的晚期演化

From GRB to Late-Time X-ray Flares:Late-Time Activity of the Central Engine

选取Swift卫星从2005年5月—2015年4月间观测的具有显著X射线耀发的已知红移的γ射线暴,共200个X射线耀发,分析γ暴本身的各向同性能Eγ,iso和晚期每个X射线耀发0.3~10 ke V波段的各向同性能E_(X,iso),比较它们的演化。研究发现:Eγ,iso和E_(X,iso)的分布没有显著区别,并且都满足高斯分布,但是Eγ,iso比E_(X,iso)高两个数量级。对γ暴本身和X射线耀发平均流量分布的统计结果显示,γ暴本身的流量也比X射线耀发高两个数量级。说明X射线耀发可能是中心引擎在晚期的活动产生的,但是中心引擎的活动在后期不断衰减,引起总的能量在降低。

In this paper , we analyzed 200 significant X-ray flares with redshifts from the GRBs observed by Swift from March 2005 to April 2015. We analyzed the isotropic energy distributions of the prompt emission and the X-ray flares , and compared their evolution. The results show that the distributions , both of Gaussian distributions, do not show significant differences between X-ray flares and the prompt emission , and the 0. 3-10 keV isotropic energy of X-ray flares distribution is about two orders of magnitude less than GRBs prompt emission. Distribution of the fluence for prompt emission and the mean fluence of the X-ray flares also show the fluence of X-ray flares is two orders of magnitude less than the GRBs prompt emission. The results suggest that X-ray flares are probably related to the late time activity of the central engine while the central engine activity continue to decline in the late period causing the total energy to reduce.