arXiv 1701.044152017-01astro-ph.CO

观测可见性掩模的不确定性及其对有偏示踪剂聚类的影响

Uncertainty in the visibility mask of a survey and its effects on the clustering of biased tracers

Manuel Colavincenzo, Pierluigi Monaco, Emiliano Sefusatti, Stefano Borgani

备注：: 23 pages, 6 figures - Minor changes
DOI：: 10.1088/1475-7516/2017/03/052

摘要：

如果不适当量化前景去除（或其他系统学，如0点测光偏移）引起的误差，则无法实现即将进行的大尺度结构勘测的预测精度。由于这些误差在天空中高度相关，预计它们的影响在非常大的尺度上特别重要。在这项工作中，我们量化的不确定性的能见度掩模的调查影响测量的功率谱的示踪剂的密度场及其协方差矩阵的样本。我们从周期性宇宙学盒子中的10，000个暗物质晕目录开始，用皮诺乔近似方法产生。为了使分析方法可行，我们假设亮度无关的晕偏置和理想化的几何形状的可见性掩模。我们发现，这些有偏示踪剂的功率谱可以表示为一个宇宙学项，掩模项和一个涉及他们的卷积项的总和。掩模和卷积项的比例类似于$P\propto l^2σ_A^2$，其中$σ_A^2$是可见性掩模上的不确定性方差。对于$l=30-100$ Mpc $/h$和$σ_A=5-20$，掩码项可以在$k\sim0.01-0.1\ h/$ Mpc处是显著的，并且卷积项可以总计为总数的$\sim 1-10$。对于功率谱协方差，卷积项与其他两个项的耦合产生了几个混合项，我们使用模拟目录通过差异来量化。这些被发现是相同的顺序的掩模协方差，并在大尺度上引入非对角项。然后，功率谱协方差矩阵不能表示为宇宙和掩模项的总和。我们的研究结果奠定了理论基础，以量化的影响，在掩模校准的不确定性，从大型光谱调查的宇宙学约束的推导。[摘要]

英文摘要：

The forecasted accuracy of upcoming surveys of large-scale structure cannot be achieved without a proper quantification of the error induced by foreground removal (or other systematics like 0-point photometry offset). Because these errors are highly correlated on the sky, their influence is expected to be especially important at very large scales. In this work we quantify how the uncertainty in the visibility mask of a survey influences the measured power spectrum of a sample of tracers of the density field and its covariance matrix. We start from a very large set of 10,000 catalogs of dark matter halos in periodic cosmological boxes, produced with the PINOCCHIO approximate method. To make an analytic approach feasible, we assume luminosity-independent halo bias and an idealized geometry for the visibility mask. We find that the power spectrum of these biased tracers can be expressed as the sum of a cosmological term, a mask term and a term involving their convolution. The mask and convolution terms scale like $P\propto l^2σ_A^2$, where $σ_A^2$ is the variance of the uncertainty on the visibility mask. With $l=30-100$ Mpc$/h$ and $σ_A=5-20$\%, the mask term can be significant at $k\sim0.01-0.1\ h/$Mpc, and the convolution term can amount to $\sim 1-10$\% of the total. For the power spectrum covariance, the coupling of the convolution term with the other two gives rise to several mixed terms, that we quantify by difference using the mock catalogs. These are found to be of the same order of the mask covariance, and to introduce non-diagonal terms at large scales. Then, the power spectrum covariance matrix cannot be expressed as the sum of a cosmological and of a mask term. Our results lie down the theoretical bases to quantify the impact that uncertainties in the mask calibration have on the derivation of cosmological constraints from large spectroscopic surveys. [Abridged]

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