宇宙γ暴距离及分布

Distance Scale and Distribution of the Cosmological γ-ray Bursts

γ暴是宇宙空间中短时标γ射线突然增亮的现象.在考虑γ暴的宇宙膨胀效应、喷流效应、以及γ暴与超新星成协现象后研究了γ暴的空间分布,假设γ暴张角是高斯分布,爆发率与恒星形成率成正比,找到最佳拟合参数值为θ0=0.1,σ=1,可说明γ暴的张角集中在0.1附近,这与目前对已知红移的γ暴的分析是一致的.由<V/Vmax>计算得到γ暴的最远红移为4.2,γ暴的能量为1.5×1051ergs.

γ-ray burst is an astronomical phenomenon of short duration enhancement of γ-rays from cosmic space. Considering the effect of the expansion of the universe, beaming effect and the evidence that γ ray bursts are close to star-forming regions, we study the distribution of the γray bursts. Assuming the opening angle follows Gauss distribution and γ ray bursts follow the measured star formation rate, we find the best parameters that fit the theory are θ0= 0.1,σ= 0.04. This shows that the most common angle is about O.lrad, in rough agreement with the samples whose redshift haven been known. The calculated maximum redshift from< v/vmax> is 4.2 and the energy of the γ-ray burst is 1.5 ×1051 ergs.