发表机构
School of Physics and Astronomy, Shanghai Jiao Tong University; Tsung-Dao Lee Institute, Shanghai Jiao Tong University; State Key Laboratory of Dark Matter Physics; Key Laboratory for Particle Astrophysics and Cosmology (MOE)/Shanghai Key Laboratory for Particle Physics and Cosmology（上海交通大学物理与天文学院; 上海交通大学汤耀道研究所; 暗物质物理国家重点实验室; 粒子天体物理与宇宙学教育部重点实验室/上海粒子物理与宇宙学重点实验室）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究针对弱引力透镜宇宙学的重子反馈系统误差，提出三参数物质功率谱压制拟合公式，可简化为单参数形式，能准确覆盖多种宇宙学参数范围，为缓解相关误差提供了可行方案。
AI 中文摘要
重子反馈可在k≈1h/Mpc、z≈1时将物质聚束压制约10%，因此是弱引力透镜宇宙学中系统误差的主要来源。我们通过FLAMINGO、IllustrisTNG和Illustris流体动力学模拟套件中测得的比值S(k,z)≡P_hydro(k,z)/P_DMO，以及CAMELS-TNG和CAMELS-SIMBA的单参数逐次（1P）变化运行来研究该效应。我们提出了一个三参数拟合公式，该公式在k≤3h/Mpc、z≤2时，能复现除一次运行外的所有这些运行结果，最大误差小于0.03（典型误差小于0.01）；唯一的例外是Ω_m=0.1的不切实际低运行。三个参数（B₀、n和a）各有明确的物理解释：B₀设定z=0时压制的特征尺度，对应气体粒子位移尺度为B₀^(1/2)；n设定压制下限（1-Ω_b/Ω_m）^n；a设定压制峰值所在的红移z_B。此外，我们发现多数运行中B₀和z_B显著相关。对于FLAMINGO、TNG和CAMELS-TNG，n≈1。对于这些模拟，描述可简化为单参数公式，最大误差小于0.03。该公式在远离校准宇宙学的情况下仍保持准确，|ΔS|的最大值小于0.03（典型误差小于0.01），覆盖的宇宙学参数范围为Ω_m∈[0.2,0.5]、Ω_b∈[0.029,0.069]、σ₈∈[0.6,1.0]。这些结果表明，尽管重子物理的实现存在多样性，但对S(k,z)的准确描述最多仅需三个有效自由度。因此，反馈对弱引力透镜宇宙学的影响原则上可在不显著损失宇宙学约束能力的情况下被内部缓解。
英文摘要
Baryonic feedback can suppress matter clustering by $\sim 10\%$ at $k\sim 1h$/Mpc and $z\sim 1$, and is therefore a major source of systematic errors in weak lensing cosmology. We investigate this effect through the ratio $S(k,z)\equiv P_{\rm hydro}(k,z)/P_{\rm DMO}(k,z)$ measured in the FLAMINGO, IllustrisTNG, and Illustris hydrodynamical simulation suites, together with the one-parameter-at-a-time (1P) variation runs of CAMELS-TNG and CAMELS-SIMBA. We present a three-parameter fitting formula that reproduces all but one of these runs with maximum error less than $0.03$ (and typical error less than $0.01$) at $k\leq 3h/$Mpc and $z\leq 2$; the only exception is a run with unrealistically low $Ω_m=0.1$. Each of the three parameters ($B_0$, $n$, and $a$) has a clear physical interpretation: $B_0$ sets the characteristic scale of the suppression at $z=0$, corresponding to a gas particle displacement scale of $B_0^{1/2}$; $n$ sets the suppression floor $(1-Ω_b/Ω_m)^n$; and $a$ sets the redshift $z_B$ at which the suppression peaks. Furthermore, we find that $B_0$ and $z_B$ are significantly correlated for most runs. Also, $n\simeq 1$ for FLAMINGO, TNG and CAMELS-TNG. For these simulations, the description reduces to a single parameter formula with maximum error less than $0.03$. The formulas remain accurate at max$(|ΔS|)<0.03$ (and typical error less than $0.01$) for cosmologies well away from the calibration cosmology, spanning the range $Ω_m\in [0.2,0.5]$, $Ω_b\in [0.029,0.069]$ and $σ_8\in [0.6,1.0]$. These results imply that, despite the diversity of baryonic physics implementations, an accurate description of $S(k,z)$ requires at most three effective degrees of freedom. Therefore the impact of feedback on weak lensing cosmology can in principle be mitigated internally without significant loss of cosmological constraining power.
Comments24 pages, 12 figures. To be submitted to JCAP
