We present a high-significance cross-correlation of CMB lensing maps from the Atacama Cosmology Telescope (ACT) Data Release 6 (DR6) with luminous red galaxies (LRGs) from the Dark Energy Spectroscopic Instrument (DESI) Legacy Survey spectroscopically calibrated by DESI. We detect this cross-correlation at a significance of 38σ; combining our measurement with the Planck Public Release 4 (PR4) lensing map, we detect the cross-correlation at 50σ. Fitting this jointly with the galaxy auto-correlation power spectrum to break the galaxy bias degeneracy with σ8, we perform a tomographic analysis in four LRG redshift bins spanning 0.4 ≤ z ≤ 1.0 to constrain the amplitude of matter density fluctuations through the parameter combination S8× = σ8 (Ωm / 0.3)0.4. Prior to unblinding, we confirm with extragalactic simulations that foreground biases are negligible and carry out a comprehensive suite of null and consistency tests. Using a hybrid effective field theory (HEFT) model that allows scales as small as kmax = 0.6 h/ Mpc, we obtain a 3.3% constraint on S8× = σ8 (Ωm / 0.3)0.4 = 0.792+0.024-0.028 from ACT data, as well as constraints on S8×(z) that probe structure formation over cosmic time. Our result is consistent with the early-universe extrapolation from primary CMB anisotropies measured by Planck PR4 within 1.2σ. Jointly fitting ACT and Planck lensing cross-correlations we obtain a 2.7% constraint of S8× = 0.776+0.019-0.021, which is consistent with the Planck early-universe extrapolation within 2.1σ, with the lowest redshift bin showing the largest difference in mean. The latter may motivate further CMB lensing tomography analyses at z < 0.6 to assess the impact of potential systematics or the consistency of the ΛCDM model over cosmic time.

中文翻译：

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阿塔卡马宇宙学望远镜 DR6 和 DESI：宇宙时间上的结构形成，测量 CMB 透镜和发光红色星系的互相关


我们提出了来自阿塔卡马宇宙学望远镜 （ACT） 数据版本 6 （DR6） 的 CMB 透镜图与来自 暗能量光谱仪 （DESI） 遗产巡天光谱校准的发光红色星系 （LRG） 的高显著性互相关，由 DESI 进行光谱校准。我们检测到这种互相关，显著性为 38σ;将我们的测量与普朗克公开版本 4 （PR4） 透镜图相结合，我们检测到 50σ 处的互相关。将其与星系自相关功率谱拟合以打破 σ8 的星系偏置简并性，我们在 0.4 ≤ z ≤ 1.0 的四个 LRG 红移区间中进行断层分析，以通过参数组合 S8× = σ8 （Ωm / 0.3）0.4 来约束物质密度波动的幅度。在揭盲之前，我们通过星系外模拟确认前景偏差可以忽略不计，并执行一套全面的零和一致性测试。使用允许小至 kmax = 0.6 h/ Mpc 的尺度的混合有效场论 （HEFT） 模型，我们从 ACT 数据中获得 S×8 = σ8 （Ωm / 0.3）0.4 = 0.792+0.024-0.028 的 3.3% 约束，以及探测宇宙时间结构形成的 S8×（z） 的约束。我们的结果与普朗克 PR4 在 1.2σ 内测量的初级 CMB 各向异性的早期宇宙外推一致。联合拟合 ACT 和普朗克透镜互相关，我们得到 S8× = 0.776+0.019-0.021 的 2.7% 约束，这与 2.1σ 以内的普朗克早期宇宙外推一致，最低的红移区间显示最大的均值差异。后者可能会促使在 z < 0.6 处进一步进行 CMB 透镜断层扫描分析，以评估潜在系统学的影响或 ΛCDM 模型在宇宙时间上的一致性。