论文标题
计数概率的差异和协方差
The Variance and Covariance of Counts-in-Cells Probabilities
论文作者
论文摘要
计数（CIC）测量值包含大量宇宙学信息，但很少用于限制理论。尽管我们可以预测给定宇宙学的分布形状，但要将模型拟合到观察到的CIC概率需要协方差矩阵 - 一个概率箱中计数的差异和不同箱中计数之间的协方差。迄今为止，这些差异还没有一般表达。在这里，我们表明密度场特定级别或“切片”的相关性决定了CIC概率的方差和协方差。我们得出了明确的公式，这些公式可以准确预测模拟星系目录的亚参数之间的方差和协方差，从而为使用CIC测量值开辟了用于宇宙学参数估计的大门。
Counts-in-cells (CIC) measurements contain a wealth of cosmological information yet are seldom used to constrain theories. Although we can predict the shape of the distribution for a given cosmology, to fit a model to the observed CIC probabilities requires the covariance matrix -- both the variance of counts in one probability bin and the covariance between counts in different bins. To date, there have been no general expressions for these variances. Here we show that correlations of particular levels, or "slices," of the density field determine the variance and covariance of CIC probabilities. We derive explicit formulae that accurately predict the variance and covariance among subvolumes of a simulated galaxy catalog, opening the door to the use of CIC measurements for cosmological parameter estimation.
