发表机构
National Centre for Nuclear Research; Center for Theoretical Physics, Polish Academy of Sciences（国家核研究中心; 波兰科学院理论物理中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出基于模拟校准的成对速度似然函数，利用非线性尺度信息，将宇宙学参数约束精度提升70%-86%，为未来巡天数据分析提供验证框架。
AI 中文摘要
本征速度直接追踪引力动力学，补充了基于密度的成团分析，正值宽视场光谱巡天（DESI、Euclid、PFS）和运动学Sunyaev-Zel'dovich（kSZ）测量进入精度时代。成对速度和成对kSZ信号的观测分析仍主要局限于线性和准线性尺度（$\gtrsim20-30$ $h^{-1}Mpc$），尽管在更小间隔处存在大量宇宙学信息。我们提出了一个基于模拟校准的$v_{12}(r,a)$似然函数，建立在精确的成对守恒方程和PyCAMB HMcode-2020非线性成团基础上，并在QUIJOTE和TNG300-3模拟套件中针对分辨率、粒子采样、盒尺寸和红移进行了验证。使用QUIJOTE，我们表明将拟合扩展到非线性尺度，相对于线性区基线（$r_{\rm min}=50$ $h^{-1}Mpc$），在$z=0.5$（$r_{\rm min}=4$ $h^{-1}Mpc$）时，$\u03a9_\mathrm{m}$和$\u03c3_8$的$1\sigma$不确定性分别收紧$74\\%$和$81\\%$，在$z=0$（$r_{\rm min}=8$ $h^{-1}Mpc$）时分别收紧$70\\%$和$74\\%$（所有情况固定$r_{max}=140$ $h^{-1}Mpc$）；$\u03c3(f\u03c3_8)$最多收紧$86\\%$，联合$\u03a9_\mathrm{m}$-$f\u03c3_8$品质因数相对于相同基线最多提高$9.1\times$。这些约束以$h$固定在其QUIJOTE基准值为条件，因为与$\u03c3_8$存在近简并响应；联合采样$h$会显著移动并加宽这些约束。该框架为在即将到来的直接本征速度、红移空间和kSZ分析中利用这些信息提供了经过验证的途径。
英文摘要
Peculiar velocities trace gravitational dynamics directly, complementing density-based clustering as wide-field spectroscopic surveys (DESI, Euclid, PFS) and kinetic Sunyaev-Zel'dovich (kSZ) measurements enter the precision era. Observational analyses of pairwise velocities and the pairwise kSZ signal remain largely restricted to linear and quasi-linear scales ($\gtrsim20-30$ $h^{-1}Mpc$), despite substantial cosmological information available at smaller separations. We present a simulation-calibrated likelihood for $v_{12}(r,a)$, built on the exact pair conservation equation and PyCAMB HMcode-2020 non-linear clustering, and validate it against the QUIJOTE and TNG300-3 suites across resolution, particle sampling, box size, and redshift. Using QUIJOTE, we show that extending the fit to non-linear scales tightens the $1σ$ uncertainty on $Ω_\mathrm{m}$ and $σ_8$ by $74\%$ and $81\%$ at $z=0.5$ ($r_{\rm min}=4$ $h^{-1}Mpc$), and by $70\%$ and $74\%$ at $z=0$ ($r_{\rm min}=8$ $h^{-1}Mpc$), relative to the linear-regime baseline ($r_{\rm min}=50$ $h^{-1}Mpc$) (all at fixed $r_{max}=140$ $h^{-1}Mpc$); $σ(fσ_8)$ tightens by up to $86\%$, and the joint $Ω_\mathrm{m}$-$fσ_8$ Figure-of-Merit improves by up to $9.1\times$ relative to the same baseline. These constraints are conditional on $h$ fixed at its QUIJOTE fiducial value, due to a near-degenerate response with $σ_8$; jointly sampling $h$ shifts and widens them substantially. This framework provides a validated route to exploiting that information in upcoming direct peculiar-velocity, redshift-space, and kSZ analyses.
Comments11 pages plus references, 8 figures, 3 tables. Submitted to Physical Review D. Comments welcome
