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arXiv 0705.0343astro-ph
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来自高红移星系巡天的星系双谱:原始非高斯性和非线性星系偏置

The bispectrum of galaxies from high-redshift galaxy surveys: primordial non-Gaussianity and non-linear galaxy bias

Emiliano Sefusatti, Eiichiro Komatsu

摘要:

在解释任何调查的星系团数据时,最大的挑战是星系偏差。使用一个简单的Fisher矩阵分析,我们表明,双谱提供了一个很好的确定线性和非线性偏置参数的中间和高Z星系,当所有可测量的三角形配置下降到轻度非线性尺度,微扰理论仍然有效,包括在内。双谱也是对原始非高斯性的有力探索。在z>2时的计划星系巡天应该会对非高斯参数产生约束,f_{NL} ^{loc.}和f_{NL} ^{eq.},与CMB实验结果相当甚至更好。我们研究了这些约束如何改善体积,红移范围,以及星系的数密度。最后,我们表明,晕占领分布可以用来进一步提高这些约束,通过解除重力,偏见和原始非高斯之间的退化。

英文摘要:

The greatest challenge in the interpretation of galaxy clustering data from any surveys is galaxy bias. Using a simple Fisher matrix analysis, we show that the bispectrum provides an excellent determination of linear and non-linear bias parameters of intermediate and high-z galaxies, when all measurable triangle configurations down to mildly non-linear scales, where perturbation theory is still valid, are included. The bispectrum is also a powerful probe of primordial non-Gaussianity. The planned galaxy surveys at z>2 should yield constraints on non-Gaussian parameters, f_{NL}^{loc.} and f_{NL}^{eq.}, that are comparable to, or even better than, those from CMB experiments. We study how these constraints improve with volume, redshift range, as well as the number density of galaxies. Finally, we show that a halo occupation distribution may be used to improve these constraints further by lifting degeneracies between gravity, bias, and primordial non-Gaussianity.

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