arXiv 2406.025042024-06-04astro-ph.CO

迈向用于探测修改引力的最优标记相关函数分析

Towards an optimal marked correlation function analysis for the detection of modified gravity

Martin Kärcher, Julien Bel, Sylvain de la Torre

备注：: 27 pages, 22 figures, submitted to A&A
发表信息：: A&A 694, A253 (2025)
DOI：: 10.1051/0004-6361/202450977

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AI总结：

本文提出结合环境型tanh标记与散粒噪声校正的标记二点相关函数分析，以增强f(R)、nDGP等修改引力与GR的区分能力。

摘要：

修改引力（MG）理论已成为解释宇宙晚期加速膨胀的一种有前景的替代方案。然而，由于屏蔽机制会在高密度区域掩盖任何偏离广义相对论（GR）的效应，在大尺度结构观测中探测MG仍然具有挑战性。标记二点相关函数为潜在探测MG信号提供了一种有前景的方法。本工作研究了基于大尺度环境估计、同时利用低密度与高密度区域中天体之间反相关性的新型标记。这是首次深入研究依赖密度的标记相关函数中的离散效应。我们利用ELEPHANT模拟评估各种标记区分GR与MG的性能，该模拟包含GR以及f(R)和nDGP引力的实现。此外，我们使用高密度Covmos星表研究离散效应。我们建立了一种稳健的散粒噪声效应校正方法，能够在很宽的尺度范围内以低于5%的精度恢复真实信号。我们发现这种校正对于无偏地测量标记相关函数的振幅至关重要。此外，我们证明，使低密度和高密度区域中的天体反相关的标记属于区分MG与GR最有效的标记之一。我们报告，在实空间中直至约80 h^-1 Mpc的尺度，|f_R0|=10^-6的f(R)与GR模拟之间的标记相关函数差异达到3–5σ量级。红移空间单极子表现出相似的特征和性能。所提出的tanh标记与散粒噪声校正相结合，为在当前和未来星系光谱巡天中采用最优方法探测MG铺平了道路。

英文摘要：

Modified gravity (MG) theories have emerged as a promising alternative to explain the late-time acceleration of the Universe. However, the detection of MG in observations of the large-scale structure remains challenging due to the screening mechanisms that obscure any deviations from General Relativity (GR) in high-density regions. The marked two-point correlation function offers a promising approach to potentially detect MG signals. This work investigates novel marks based on large-scale environment estimates but also that exploit the anti-correlation between objects in low- and high-density regions. This is the first time discreteness effects in density-dependent marked correlation functions are investigated in depth. We assess the performance of various marks to distinguish GR from MG by using the ELEPHANT simulations, comprised of realisations of GR as well as $f(R)$ and nDGP gravity. In addition, discreteness effects are studied using the high-density Covmos catalogues. We establish a robust method to correct for shot-noise effects that allows the recovery of the true signal with an accuracy below $5\%$ over a wide range of scales. We find such correction to be crucial to measure the amplitude of the marked correlation function in an unbiased manner. Furthermore, we demonstrate that marks, anti-correlating objects in low- and high-density regions, are among the most effective in distinguishing between MG and GR. We report differences in the marked correlation function between $f(R)$ with $|f_{R0}|=10^{-6}$ and GR simulations of the order of 3-5$σ$ in real space up to scales of about $80\, h^{-1} \, {\rm Mpc}$. The redshift-space monopole exhibits similar features and performances. The combination of the proposed $\tanh$-mark with shot-noise correction paves the way towards an optimal approach for the detection of MG in current and future galaxy spectroscopic surveys.

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