An optical spectrum of the afterglow of a γ-ray burst at a redshift of z=6.295
An optical spectrum of the afterglow of a γ-ray burst at a redshift of z=6.295
复制标题
DOI：
10.1038/nature04498
复制
发表时间：
2006-03-09
期刊：
影响因子：
64.8
通讯作者：
Yoshida, A
中科院分区：
文献类型：
--
作者：
Kawai, N;Kosugi, G;Yoshida, A
伽马射线暴（GRBs）的快速伽马射线发射应该可以探测到z bbbb10的距离（参考文献1），因此应该为宇宙恒星形成的演化、星系间介质的再电离和宇宙的金属富集历史提供一个很好的探测（1-4）。迄今为止，GRB测量到的最高红移是z = 4.50（参考文献5）。这里我们报道了爆发后3.4天获得的GRB 050904余辉的光谱；在光谱的长波长端显示出一个清晰的连续体，在大约9000埃处由于z近似为6.3的Lyman α吸收（带有阻尼翼）而有一个明显的截止。在z = 6.295 +/- 0.002的重元素吸收谱线系统也被检测到，得到了红移的精确测量。Si II精细结构线表明，在GRB的前身周围有一个密集的、富含金属的环境。
The prompt gamma-ray emission from gamma-ray bursts (GRBs) should be detectable out to distances of z > 10 (ref. 1), and should therefore provide an excellent probe of the evolution of cosmic star formation, reionization of the intergalactic medium, and the metal enrichment history of the Universe(1-4). Hitherto, the highest measured redshift for a GRB has been z = 4.50 (ref. 5). Here we report the optical spectrum of the afterglow of GRB 050904 obtained 3.4 days after the burst; the spectrum shows a clear continuum at the long-wavelength end of the spectrum with a sharp cut-off at around 9,000 angstrom due to Lyman alpha absorption at z approximate to 6.3 (with a damping wing). A system of absorption lines of heavy elements at z = 6.295 +/- 0.002 was also detected, yielding the precise measurement of the redshift. The Si II fine-structure lines suggest a dense, metal-enriched environment around the progenitor of the GRB.