开发了一个用于大尺度结构数据角功率谱分析的统一流水线-- II。放大率偏差和射电连续谱测量的个例研究
Developing a unified pipeline for large-scale structure data analysis with angular power spectra -- II. A case study for magnification bias and radio continuum surveys
摘要：
继我们的目的开发一个统一的管道大尺度结构数据分析与角（即谐波空间）功率谱，我们现在包括弱透镜效应的放大偏差星系集群在一个公开的，模块化的参数估计代码。因此，我们预测的一致性宇宙学模型，暗能量，并从星系团层析角功率谱修改引力理论的参数的约束。我们发现，一个正确的放大率建模是至关重要的，以便不偏宇宙学参数的估计，特别是在深星系调查的情况下。我们的案例研究采用了宇宙演化图（EMU）的规范，这是一个全天，深射电连续谱调查，并预计将探测宇宙红移$z\sim6$。我们假设林伯近似，并包括放大率偏差的密度波动和红移空间扭曲。通过将我们的分析限制在Limber近似成立的区域，与精确计算相比，我们显着减少了所需的计算时间。我们还表明，有一个趋势，从忽视放大率时，红移箱是非常宽的偏置参数估计。我们的结论是，这一结果意味着一个很强的依赖于透镜的贡献，这是一个综合的效果，并成为占主导地位时，宽红移箱被认为是。最后，我们注意到，而不是被认为是一种污染物，放大偏差编码重要的宇宙学信息，它的列入导致星系偏差和振幅归一化的物质波动之间的简并性的缓解。
英文摘要：
Following on our purpose of developing a unified pipeline for large-scale structure data analysis with angular (i.e. harmonic-space) power spectra, we now include the weak lensing effect of magnification bias on galaxy clustering in a publicly available, modular parameter estimation code. We thus forecast constraints on the parameters of the concordance cosmological model, dark energy, and modified gravity theories from galaxy clustering tomographic angular power spectra. We find that a correct modelling of magnification is crucial in order not to bias the estimation of cosmological parameters, especially in the case of deep galaxy surveys. Our case study adopts specifications of the Evolutionary Map of the Universe (EMU), which is a full-sky, deep radio-continuum survey, and is expected to probe the Universe up to redshift $z\sim6$. We assume the Limber approximation, and include magnification bias on top of density fluctuations and redshift-space distortions. By restricting our analysis to the regime where the Limber approximation holds true, we significantly minimise the computational time needed, compared to that of the exact calculation. We also show that there is a trend for more biased parameter estimates from neglecting magnification when the redshift bins are very wide. We conclude that this result implies a strong dependence on the lensing contribution, which is an integrated effect and becomes dominant when wide redshift bins are considered. Finally, we note that instead of being considered a contaminant, magnification bias encodes important cosmological information, and its inclusion leads to an alleviation of the degeneracy between the galaxy bias and the amplitude normalisation of the matter fluctuations.
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