论文标题
红移空间中的光环双光谱
The Halo Bispectrum Multipoles in Redshift Space
论文作者
论文摘要
我们介绍了从红移空间中的光环双光谱，其多孔，单子，四极和六烷基的分析。我们在扰动理论中使用树级模型拟合此类测量，该模型取决于线性和非线性偏置参数以及密度波动的增长率$ f $。可能性分析利用了一大批模拟目录，从而可以对所有多物的协方差属性进行强有力的估计。我们将协方差矩阵的数值估计与其高斯预测相比，所有配置的差异均为10％或更少，而在单极案例中挤压三角形的唯一除外。我们找到了树级模型的有效性范围，对于约1000 $ h^{ - 3} \，{\ rm gpc}^3 $的总模拟量的最大挥发器为$ 0.08 \，h \，h \，h \，{\ rm mpc}^{ - 1} $ and Monopole $ and $0。 \，\ rm {mpc}^{ - 1} $分别用于Quadrupole和Hexadecapole。尽管如此，在分析中添加四极杆又可以对模型参数（特别是$ f $）的确定进行重大改进，这与功率谱案例类似。最后，我们将完整协方差的数值估计与其在高斯近似中的理论预测进行了比较，并在具有周期性边界条件的模拟框的背景下发现后者非常好。
We present the analysis of the halo bispectrum in redshift-space in terms of its multipoles, monopole, quadrupole and hexadecapole, measured from a large set of simulations. We fit such measurements with a tree-level model in perturbation theory that depends on linear and nonlinear bias parameters as well as on the growth rate $f$ of density fluctuations. The likelihood analysis takes advantage of a very large set of mock catalogs, enabling a robust estimation of the covariance properties for all multipoles. We compare the numerical estimate of the covariance matrix to its Gaussian prediction finding discrepancies of 10% or less for all configurations with the sole exception of the squeezed triangles in the monopole case. We find the range of validity of the tree-level model, for the total simulation volume of about 1000 $h^{-3}\, {\rm Gpc}^3$, reaches a maximum wavenumber of $0.08 \, h \, {\rm Mpc}^{-1}$ for the monopole, while it is limited to $0.06$ and $0.045\, h \, \rm{Mpc}^{-1}$ respectively for quadrupole and hexadecapole. Despite this, the addition of the quadrupole to the analysis allows for significant improvements on the determination of the model parameters and specifically on $f$, similarly to the power spectrum case. Finally, we compare our numerical estimate for the full covariance with its theoretical prediction in the Gaussian approximation and find the latter to work remarkably well in the context of simulation boxes with periodic boundary condition.
