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Haislip JB Nysewander MC Reichart DE Levan A Tanvir N Cenko SB Fox DB Price PA Castro-Tirado AJ Gorosabel J Evans CR Figueredo E MacLeod CL Kirschbrown JR Jelinek M Guziy S de Ugarte Postigo A Cypriano ES LaCluyze A Graham J Priddey R Chapman R Rhoads J Fruchter AS Lamb DQ Kouveliotou C Wijers RA Bayliss MB Schmidt BP Soderberg AM Kulkarni SR Harrison FA Moon DS Gal-Yam A Kasliwal MM Hudec R Vitek S Kubanek P Crain JA Foster AC Clemens JC Bartelme JW Canterna R Hartmann DH Henden AA Klose S 《Nature》2006,440(7081):181-183
Gamma-ray bursts (GRBs) and their afterglows are the most brilliant transient events in the Universe. Both the bursts themselves and their afterglows have been predicted to be visible out to redshifts of z approximately 20, and therefore to be powerful probes of the early Universe. The burst GRB 000131, at z = 4.50, was hitherto the most distant such event identified. Here we report the discovery of the bright near-infrared afterglow of GRB 050904 (ref. 4). From our measurements of the near-infrared afterglow, and our failure to detect the optical afterglow, we determine the photometric redshift of the burst to be z = 6.39 - 0.12 + 0.11 (refs 5-7). Subsequently, it was measured spectroscopically to be z = 6.29 +/- 0.01, in agreement with our photometric estimate. These results demonstrate that GRBs can be used to trace the star formation, metallicity, and reionization histories of the early Universe. 相似文献
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研究管状曲面和它的平行曲面的奇点问题.所谓管状曲面,是沿着E3里一条曲线的双参数空间运动产生的.选定曲线的Frenet向量T作为旋转轴,用不同的方法得到了运动管状曲面的特征.然后,给出管状曲面奇点的一些定理和结果. 相似文献
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