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Power spectrum response of large-scale structure in 1D and in 3D: tests of prescriptions for post-collapse dynamics
Monthly Notices of the Royal Astronomical Society ( IF 4.8 ) Pub Date : 2020-09-19 , DOI: 10.1093/mnras/staa2878 Anaëlle Halle 1, 2 , Takahiro Nishimichi 3, 4 , Atsushi Taruya 3, 4 , Stéphane Colombi 5 , Francis Bernardeau 5, 6
Monthly Notices of the Royal Astronomical Society ( IF 4.8 ) Pub Date : 2020-09-19 , DOI: 10.1093/mnras/staa2878 Anaëlle Halle 1, 2 , Takahiro Nishimichi 3, 4 , Atsushi Taruya 3, 4 , Stéphane Colombi 5 , Francis Bernardeau 5, 6
Affiliation
The power spectrum response function of the large-scale structure of the Universe describes how the evolved power spectrum is modified by a small change in initial power through non-linear mode coupling of gravitational evolution. It was previously found that the response function for the coupling from small to large scales is strongly suppressed in amplitude, especially at late times, compared to predictions from perturbation theory (PT) based on the single-stream approximation. One obvious explanation for this is that PT fails to describe the dynamics beyond shell-crossing. We test this idea by comparing measurements in $N$-body simulations to prescriptions based on PT but augmented with adaptive smoothing to account for the formation of non-linear structures of various sizes in the multi-stream regime. We first start with one-dimensional (1D) cosmology, where the Zel'dovich approximation provides the exact solution in the single stream regime. Similarly to the 3D case, the response function of the large-scale modes exhibits a strong suppression in amplitude at small scales which cannot be explained by the Zel'dovich solution alone. However, by performing adaptive smoothing of initial conditions to identify haloes of different sizes and solving approximately post-collapse dynamics in the 3-streams regime, agreement between theory and simulations drastically improves. We extend our analyses to the 3D case using PINOCCHIO algorithm, in which similar adaptive smoothing is implemented on the Lagrangian PT fields to identify haloes and is combined with a spherical halo prescription to account for post-collapse dynamics. Again, a suppression is found in the coupling between small- and large-scale modes and the agreement with simulations is improved.
中文翻译:
1D 和 3D 中大尺度结构的功率谱响应:倒塌后动力学处方的测试
宇宙大尺度结构的功率谱响应函数描述了演化的功率谱如何通过引力演化的非线性模式耦合,初始功率的微小变化被修改。先前发现,与基于单流近似的扰动理论 (PT) 的预测相比,从小到大尺度耦合的响应函数在幅度上受到强烈抑制,尤其是在后期。对此的一个明显解释是 PT 未能描述超越壳层的动力学。我们通过将 $N$-body 模拟中的测量值与基于 PT 的处方进行比较来测试这个想法,但增加了自适应平滑以解释在多流状态下各种尺寸的非线性结构的形成。我们首先从一维 (1D) 宇宙学开始,其中 Zel'dovich 近似提供了单流状态下的精确解。与 3D 情况类似,大尺度模式的响应函数在小尺度上表现出强烈的幅度抑制,这无法仅用 Zel'dovich 解来解释。然而,通过对初始条件进行自适应平滑以识别不同大小的晕圈并在 3 流状态下解决近似坍塌后的动力学问题,理论与模拟之间的一致性得到了显着提高。我们使用 PINOCCHIO 算法将我们的分析扩展到 3D 案例,其中在拉格朗日 PT 场上实施类似的自适应平滑以识别晕圈,并结合球形晕圈处方来解释坍塌后的动态。再次,
更新日期:2020-09-19
中文翻译:
1D 和 3D 中大尺度结构的功率谱响应:倒塌后动力学处方的测试
宇宙大尺度结构的功率谱响应函数描述了演化的功率谱如何通过引力演化的非线性模式耦合,初始功率的微小变化被修改。先前发现,与基于单流近似的扰动理论 (PT) 的预测相比,从小到大尺度耦合的响应函数在幅度上受到强烈抑制,尤其是在后期。对此的一个明显解释是 PT 未能描述超越壳层的动力学。我们通过将 $N$-body 模拟中的测量值与基于 PT 的处方进行比较来测试这个想法,但增加了自适应平滑以解释在多流状态下各种尺寸的非线性结构的形成。我们首先从一维 (1D) 宇宙学开始,其中 Zel'dovich 近似提供了单流状态下的精确解。与 3D 情况类似,大尺度模式的响应函数在小尺度上表现出强烈的幅度抑制,这无法仅用 Zel'dovich 解来解释。然而,通过对初始条件进行自适应平滑以识别不同大小的晕圈并在 3 流状态下解决近似坍塌后的动力学问题,理论与模拟之间的一致性得到了显着提高。我们使用 PINOCCHIO 算法将我们的分析扩展到 3D 案例,其中在拉格朗日 PT 场上实施类似的自适应平滑以识别晕圈,并结合球形晕圈处方来解释坍塌后的动态。再次,