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arXiv 0801.4516astro-phhep-ph
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寻找10^{19}以上的Cosmic-Ray源eV和大尺度结构之间的相关性

Searching for a Correlation Between Cosmic-Ray Sources Above 10^{19} eV and Large-Scale Structure

Tamar Kashti, Eli Waxman

摘要:

我们研究的各向异性签名,这是预期的,如果超高能量,>10^{19} eV,宇宙射线(UHECR)的来源是河外和跟踪大尺度分布的发光物质。利用PSCz星系表作为大尺度结构(LSS)的示踪物,我们得到了UHECR强度的预期全天角分布。我们定义了一个统计量,测量预测和观察到的UHECR到达方向分布之间的相关性,并表明它比功率谱和两点关联函数对预期的各向异性签名更敏感。相关统计量的分布对未知的UHECR源密度红移演化和未知的星系间磁场强度和结构不敏感。我们发现,使用这个统计,最近公布的> 5.7 × 10 ^{19} eV俄歇数据不符合各向同性在~98% CL,并符合源分布的痕迹LSS,与一些偏好的源分布,是有偏见的星系分布。各向异性特征在较低的能量(> 4x 10 ^{19} eV)下也应该是可检测的。俄歇暴露量增加几倍可能会将显着性增加到> 99%CL,但不会增加到> 99.9%CL(除非UHECR源密度与星系相当或大于星系)。为了区分不同的偏差模型,实验的绝对能量校准中的系统不确定度应降低到远低于当前的~ 25%。

英文摘要:

We study the anisotropy signature which is expected if the sources of ultra high energy, >10^{19} eV, cosmic-rays (UHECRs) are extragalactic and trace the large scale distribution of luminous matter. Using the PSCz galaxy catalog as a tracer of the large scale structure (LSS), we derive the expected all sky angular distribution of the UHECR intensity. We define a statistic, that measures the correlation between the predicted and observed UHECR arrival direction distributions, and show that it is more sensitive to the expected anisotropy signature than the power spectrum and the two point correlation function. The distribution of the correlation statistic is not sensitive to the unknown redshift evolution of UHECR source density and to the unknown strength and structure of inter-galactic magnetic fields. We show, using this statistic, that recently published >5.7x10^{19} eV Auger data are inconsistent with isotropy at ~98% CL, and consistent with a source distribution that traces LSS, with some preference to a source distribution that is biased with respect to the galaxy distribution. The anisotropy signature should be detectable also at lower energy, >4x10^{19} eV. A few fold increase of the Auger exposure is likely to increase the significance to >99% CL, but not to >99.9% CL (unless the UHECR source density is comparable or larger than that of galaxies). In order to distinguish between different bias models, the systematic uncertainty in the absolute energy calibration of the experiments should be reduced to well below the current ~25%.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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