单峰伽玛射线暴光变曲线的FWHM与持续时间之间的关系

The relationship between FWHM and durationof single peaked GRB light curves

探讨了具有单峰结构的伽玛射线暴(GRB)光变曲线的半峰全宽(FWHM)与伽玛暴持续时标T之间的关系.用目前公认的半经验公式———Kocevski,Ryde & Liang(2003)模型对108个单峰光变曲线数据样本进行拟合,选取59个χ2<2的有效拟合样本计算FWHM,然后对FWHM与T进行相关分析.两者能较好地用幂率关系进行拟合为T≈BWa,其中W为光变曲线的FWHM,a与B为常数.结果表明,单峰GRB光变曲线的FWHM与T90(伽玛暴光子计数在5%—95%之间的持续时标)对数值之间有很好的线性相关性,相关系数R=0·72,而FWHM与T50(伽玛暴光子计数在25%—75%之间的持续时标)的相关更紧密,相关系数R=0·93.这表明GRB的光变曲线结构与其持续时间有密切的关系,光变曲线的FWHM越宽,则持续时标越长.

We explored the relation between FWHMs of single pulses in a sample of GRB （Gamma-Ray Burst） light curves and durations of the GRBs. Based on a sample of 108 single-peaked GRB light curves, we fitted these sample data with Kocevski, Ryde ＆ Liang （2003） model. A sub-sample containing 59 pulses with χ^2 〈 2 is selected to test whether there is a relation between FWHM of the pulses and the duration of GRBs or not. The relation between these two quantities is well fitted with T≈BWa , where T is the duration, W is the FWHM, a and B are constants. Our result shows that there does exist a proportional correlation between the logarithm of FWHMs and the logarithm of T90 （duration containing from 5 % to 95 % of the total fluence of a GRB） of GRB light curves with a correlation coefficient R = 0.72. The proportional correlation between the logarithm of FWHMs and the logarithm of T50 （duration containing from 25% to 75% of the total fluence of a GRB） is more tight with a larger correlation coefficient R=0.93. Our finding shows that the light curve structure is correlated to the GRB duration. A larger FWHM corresponds to a longer GRB.