星系-电子交叉功率谱：ACT、SPT-3G 与 DESI 亮红星系
The galaxy-electron cross-spectrum with ACT, SPT-3G and DESILS LRGs
- Perimeter Institute for Theoretical Physics（Perimeter理论物理研究所）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
利用 ACT 和 SPT-3G 的 kSZ 信号与 DESI LRG 交叉相关，首次测量星系-电子功率谱，以 12.3σ 显著性探测，并约束维里半径内气体占比为 25%–33%。
AI中文摘要：
星系-电子交叉功率谱 $P_{ge}(k)$ 测量星系周围气体的亚度分布，该分布受反馈过程重塑。我们利用光度型 DESI 遗产巡天亮红星系的运动学 Sunyaev-Zel'dovich（kSZ）信号测量 $P_{ge}$，将速度加权的星系动量模板与 ACT DR6 以及首次使用的 SPT-3G 的 CMB 温度进行交叉相关。交叉谱的绝对归一化由替代场蒙特卡洛方法固定，该方法传播巡天掩膜、光锥演化和光度红移权重，将测量的伪谱转换为物理单位下的 $P_{ge}(k)$。我们以 $11.7\sigma$ 的显著性用 ACT 探测到 $P_{ge}$，以 $8.4\sigma$ 用 SPT-3G 探测到，结合 SPT-3G 与 ACT 北天区（两者不重叠）时显著性达到 $12.3\sigma$。两个巡天具有独立的光学系统、波束、滤波和噪声，并共享约三分之二的 SPT-3G 星系；它们的振幅逐通道一致，最大差异为 $0.7\sigma$。对所采用的夜晚巡天图进行的全部 $26$ 项零检验均与零信号一致，其中包括六项 ACT 频率差、三项 SPT-3G 频率差以及主选样的四项 ACT 天区差异。将振幅转化为气体比例需要样本的宿主暗晕质量，而交叉谱本身无法测量该质量；从测量的数密度和已发表的同一星系的 CMB 透镜校准中获取宿主暗晕质量后，维里半径内的气体占暗晕宇宙重子预算的 $25\\%$--$33\\%$。
英文摘要：
The galaxy--electron cross-power spectrum $P_{ge}(k)$ measures the small-scale distribution of gas around galaxies, the quantity reshaped by feedback. We measure $P_{ge}$ from the kinetic Sunyaev--Zel'dovich (kSZ) signal of the photometric DESI Legacy Imaging Surveys luminous red galaxies, cross-correlating a velocity-weighted galaxy momentum template with the CMB temperature from ACT DR6 and, for the first time, SPT-3G. The absolute normalization of the cross-spectrum is fixed by a surrogate-field Monte Carlo that propagates the survey mask, lightcone evolution, and photometric-redshift weights, converting the measured pseudo-spectrum into $P_{ge}(k)$ in physical units. We detect $P_{ge}$ at $11.7σ$ with ACT and $8.4σ$ with SPT-3G, and at $12.3σ$ combining SPT-3G with the ACT northern cap, which it does not overlap. The two surveys have independent optics, beams, filtering and noise and share about two thirds of the SPT-3G galaxies; their amplitudes agree channel by channel, the largest difference being $0.7σ$. All $26$ null tests on the adopted night maps are consistent with zero signal, among them the six ACT frequency differences, the three SPT-3G frequency differences, and the four ACT cap differences of the main selection. Turning the amplitude into a gas fraction requires the host halo masses of the sample, which the cross-spectrum does not itself measure; taking them from its measured number density and from a published CMB-lensing calibration of the same galaxies, the gas within the virial radius is $25$--$33\%$ of the cosmic baryon budget of the halo.
