Gamma-Ray Bursts: New Rulers to Measure the Universe
Gamma-Ray Bursts: New Rulers to Measure the Universe
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DOI：
10.1086/424915
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发表时间：
2004-08
期刊：
影响因子：
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通讯作者：
G. Ghirlanda;G. Ghisellini;D. Lazzati;C. Firmani
中科院分区：
文献类型：
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作者：
G. Ghirlanda;G. Ghisellini;D. Lazzati;C. Firmani
对宇宙的最佳测量应该是在任何红移处使用标准的“尺子”。Ia型超新星（SN Ia）对宇宙的探测高达z ~ 1.5，而宇宙微波背景（CMB）的主要各向异性基本在z ~ 1000。显然，伽马射线暴（GRBs）几乎就是标准的蜡烛。然而，正如Ghirlanda等人所发现的，它们的发射是准直的，准直校正后的能量与脉冲的大部分辐射发射的频率密切相关。通过这种相关性，我们可以准确地推断出爆发能量，从而探测到中间红移（z < 10）宇宙。使用最著名的15次伽马射线暴，我们发现了非常令人鼓舞的结果，强调了宇宙伽马射线暴的作用。与SN Ia的拟合结果分别为ΩM = 0.37±0.10和ΩΛ = 0.87±0.23。另外假设宇宙是平坦的，则参数约束为ΩM = 0.29±0.04和ΩΛ = 0.71±0.05。grb完成了Ia超新星与CMB主各向异性之间的“缺失环节”。它们可以为暗能量的宇宙效应提供新的见解，补充了通过综合萨克斯-沃尔夫效应（Sachs-Wolfe effect）由CMB次级各向异性提供的见解。伽玛暴在宇宙学上的标准烛台作用出人意料，这让我们对伽玛暴专用卫星“雨燕”发射后所能获得的结果抱有最乐观的希望。
The best measure of the universe should be done using a standard "ruler" at any redshift. Type Ia supernovae (SN Ia) probe the universe up to z ~ 1.5, while the cosmic microwave background (CMB) primary anisotropies concern basically z ~ 1000. Apparently, gamma-ray bursts (GRBs) are all but standard candles. However, their emission is collimated, and the collimation-corrected energy correlates tightly with the frequency at which most of the radiation of the prompt is emitted, as found by Ghirlanda et al. Through this correlation we can infer the burst energy accurately enough to probe the intermediate-redshift (z < 10) universe. Using the best known 15 GRBs we find very encouraging results that emphasize the cosmological GRB role. A combined fit with SN Ia yields ΩM = 0.37 ± 0.10 and ΩΛ = 0.87 ± 0.23. Assuming in addition a flat universe, the parameters are constrained to be ΩM = 0.29 ± 0.04 and ΩΛ = 0.71 ± 0.05. GRBs accomplish the role of "missing link" between SN Ia and CMB primary anisotropies. They can provide a new insight on the cosmic effects of dark energy, complementary to the one supplied by CMB secondary anisotropies through the integrated Sachs-Wolfe effect. The unexpected standard candle cosmological role of GRBs motivates us with the most optimistic hopes for what can be obtained when the GRB-dedicated satellite, Swift, is launched.