论文标题
测量结构形成的潮汐响应：使用TREEPM的各向异性单独的宇宙模拟
Measuring the Tidal Response of Structure Formation: Anisotropic Separate Universe Simulations using TreePM
论文作者
论文摘要
我们提出各向异性的“独立宇宙”模拟，该模拟修改N体型Gadget-4，以通过各向异性扩展因子代表大规模的潮汐场。这些模拟用于测量物质功率谱对空间均匀的无跟踪潮汐场的线性，准线性和非线性响应，直至波数$ k = 7 h \ text {mpc}^{ - 1} $。加上对先前工作中测得的大规模过度密度的响应，这完全描述了挤压极限中的非线性物质双光谱。 We find that the response amplitude does not approach zero on small scales in physical coordinates, but rather a constant value at $z=0$, $R_K\approx 0.5$ for $k \geq 3 h\text{Mpc}^{-1}$ up to the scale where we consider our simulations reliable, $k \leq 7 h\text{Mpc}^{-1}$ at $ z = 0 $。这表明即使光环的内部区域也受到大规模潮汐场的影响。我们还直接测量了光环形状与潮汐场的比对，发现了一个清晰的信号，随着光环质量的增加。
We present anisotropic "separate universe" simulations which modify the N-body code Gadget-4 in order to represent a large-scale tidal field through an anisotropic expansion factor. These simulations are used to measure the linear, quasi-linear and nonlinear response of the matter power spectrum to a spatially uniform trace-free tidal field up to wavenumber $k = 7 h \text{Mpc}^{-1}$. Together with the response to a large-scale overdensity measured in previous work, this completely describes the nonlinear matter bispectrum in the squeezed limit. We find that the response amplitude does not approach zero on small scales in physical coordinates, but rather a constant value at $z=0$, $R_K\approx 0.5$ for $k \geq 3 h\text{Mpc}^{-1}$ up to the scale where we consider our simulations reliable, $k \leq 7 h\text{Mpc}^{-1}$ at $z=0$. This shows that even the inner regions of haloes are affected by the large-scale tidal field. We also measure directly the alignment of halo shapes with the tidal field, finding a clear signal which increases with halo mass.
