论文标题
宇宙物质密度领域的copula是非高斯的
The copula of the cosmological matter density field is non-Gaussian
论文作者
论文摘要
宇宙物质密度场的非高斯性可以通过局部高斯转化（及其近似值（例如logrithmic变换））大大降低。可以将这种行为重新铸造为高斯副群假说，并已在两点水平上被验证至非常高的精度。另一方面，在模拟中已经检测到高斯田中统计学意义的非高斯。我们指出，这种明显的不一致是由副函数的自由度非常有限引起的，这使其误导是对高斯领域中残留非高斯性的诊断。使用副群密度，我们强调了与高斯的偏离。我们进一步量化了其在预测的N点相关函数中的影响。我们探讨了高斯副库假设的一种补救措施，该假设减轻但不能完全解决上述问题。
Non-Gaussianity of the cosmological matter density field can be largely reduced by a local Gaussianization transformation (and its approximations such as the logrithmic transformation). Such behavior can be recasted as the Gaussian copula hypothesis, and has been verified to very high accuracy at two-point level. On the other hand, statistically significant non-Gaussianities in the Gaussianized field have been detected in simulations. We point out that, this apparent inconsistency is caused by the very limited degrees of freedom in the copula function, which make it misleading as a diagnosis of residual non-Gaussianity in the Gaussianized field. Using the copula density, we highlight the departure from Gaussianity. We further quantify its impact in the predicted n-point correlation functions. We explore a remedy of the Gaussian copula hypothesis, which alleviates but not completely solves the above problems.
