AI 中文总结
我们测量了 DESI Y1 LRG 的连通偶宇称 4PCF，在多种稳健性检验下探测到约 12-17σ 信号，为宇宙学约束和 BAO 搜索开辟了道路。
AI 中文摘要
我们展示了 DESI 第一年（Y1）发光红星系（LRGs）的连通偶宇称星系四点相关函数（4PCF）。这是对数据上连通 4PCF 的首次测量之一，并在全天分析中显示出约 12 到 17σ 的清晰探测信号。我们通过改变三个因素来测试信号的稳健性：半球（北天 vs. 南天）、红移范围（要么是完整范围 0.4 < z < 1.1，要么是更高数密度的区间 0.4 < z < 0.8），以及样本完整性（完整样本 vs. 仅在数密度驱动的截断内最完整的区域）。最后，我们对空间上充分分离的不同天区进行互相关，这些天区应具有很大程度上独立的噪声。这种方法在领头阶能够消除数据协方差矩阵与模拟协方差矩阵之间的失配；然而，在某些情况下以牺牲灵敏度为代价。我们在此方法中发现了约 15σ 的偶宇称 4PCF 证据。总体而言，这里呈现的 4PCF 研究敏感地探测了模拟目录与数据之间的任何失配，并开启了拟合模型、约束宇宙学参数和星系偏袒、以及搜索重子声学振荡（BAO）特征的前景。
英文摘要
We present the connected even-parity galaxy 4-Point Correlation Function (4PCF) of DESI Year 1 (Y1) Luminous Red Galaxies (LRGs). This is one of the first measurements of the connected 4PCF on data, and shows a clear detection at $\sim$12 to 17$σ$ in the full-sky analysis. We test the robustness of the signal by varying three factors: hemisphere (north vs. south), redshift range (either the full range $0.4 < z < 1.1$ or the higher-number-density interval $0.4 < z < 0.8$), and sample completeness (the full sample vs. only the most complete regions within the number density-motivated cut). Finally, we cross-correlate different patches that are spatially well-separated, and thus should have largely independent noise. This approach, at leading order, is able to remove mismatch between the covariance matrix of the data and that of the mocks; however, in certain cases at the cost of sensitivity. We find $\sim$15$σ$ evidence for an even-parity 4PCF in this approach. Overall, the studies of the 4PCF presented here probe sensitively any mismatch between mock catalogs and data, and also open up the prospect of fitting a model, constraining cosmological parameters and galaxy biases, and searching for Baryon Acoustic Oscillation (BAO) features.
Comments56 pages, 29 Figures
