标题： 红移空间星系双功率谱的精度分析 显示英文标题

标题： Precision analysis of the redshift-space galaxy bispectrum

摘要： 我们研究了角度平均（单极）红移空间星系三功率谱的信息内容。我们方法的主要新颖之处在于使用了一种系统性的树级扰动理论模型，该模型包括星系偏倚、红外重求和，并且还考虑了非线性红移空间畸变、分箱以及投影效应。我们分析了来自PT挑战模拟的数据，其累积体积为566$h^{-3}$Gpc$^3$，这使得与理论预测的精确比较成为可能。通过拟合我们的模拟数据的功率谱和三功率谱，并在一致的马尔可夫链蒙特卡洛分析中调整所有必要的宇宙学和非必要参数，我们发现我们的树级三功率谱模型在$k_{\max}=0.08~h{\rm Mpc}^{-1}$（在$z=0.61$时）内有效。我们还发现，加入三功率谱单极可以相对功率谱提高宇宙学参数的约束精度$(5-15)\%$倍。对于模拟星系的二次偏倚参数，这种改进更为显著，我们也展示了这些参数偏离宿主暗物质晕的偏倚达到$\sim 3\sigma$水平。 最后，我们调整协方差和尺度切割以匹配BOSS调查的体积，并估计在最小的$\Lambda$CDM模型中，三功率谱数据可以将对质量涨落振幅$\sigma_8$的约束收紧大约$10\%$。 显示英文摘要

摘要： We study the information content of the angle-averaged (monopole) redshift space galaxy bispectrum. The main novelty of our approach is the use of a systematic tree-level perturbation theory model that includes galaxy bias, IR resummation, and also accounts for nonlinear redshift space distortions, binning, and projection effects. We analyze data from the PT challenge simulations, whose cumulative volume of 566 $h^{-3}$Gpc$^3$ allows for a precise comparison to theoretical predictions. Fitting the power spectrum and bispectrum of our simulated data, and varying all necessary cosmological and nuisance parameters in a consistent Markov chain Monte Carlo analysis, we find that our tree-level bispectrum model is valid up to $k_{\max}=0.08~h{\rm Mpc}^{-1}$ (at $z=0.61$). We also find that inclusion of the bispectrum monopole improves constraints on cosmological parameters by $(5-15)\%$ relative to the power spectrum. The improvement is more significant for the quadratic bias parameters of our simulated galaxies, which we also show to deviate from biases of the host dark matter halos at the $\sim 3\sigma$ level. Finally, we adjust the covariance and scale cuts to match the volume of the BOSS survey, and estimate that within the minimal $\Lambda$CDM model the bispectrum data can tighten the constraint on the mass fluctuation amplitude $\sigma_8$ by roughly $10\%$.