利用快速射电暴与Sunyaev-Zel'dovich效应定位温热星系际介质中的缺失重子
Locating the missing baryons in the warm-hot intergalactic medium with fast radio bursts and the Sunyaev-Zel'dovich effect
AI总结：
该研究通过CHIME/FRB目录的FRB色散量与普朗克卫星的tSZ图交叉相关检测，定位到宇宙网中温热星系际介质的缺失重子，测得其重子分数为0.48，填补了本地宇宙重子预算缺口。
AI中文摘要：
晚期宇宙的传统天文普查仅能解释部分重子物质总量，流体动力学模拟预测缺失的重子以高度弥散的温热星系际介质（WHIM）形式存在于宇宙网的巨大纤维状结构中。由于其典型温度，直接观测WHIM长期以来一直是一项挑战。本研究首次报告了来自CHIME/FRB第二目录的快速射电暴（FRB）的色散量（DM）与普朗克卫星的热Sunyaev-Zel'dovich（tSZ）康普顿y图之间的空间交叉相关检测结果。通过对维里化星系团进行掩蔽以分离弥散信号，我们发现FRB与tSZ图之间存在正相关，概率大于99.77%。我们的联合参数推断约束了WHIM中的宇宙重子分数f_WHIM=0.48，其68%置信区间为0.27<f_WHIM<0.61，锚定的WHIM平均温度为2.4×10^6 K。更严格的掩蔽策略证实该信号源自WHIM而非星系团。我们的结果表明，缺失的重子存在于宇宙网内的弥散气体中，填补了本地宇宙的宇宙重子预算缺口。
英文摘要：
Traditional astronomical censuses in the late-time Universe can only account for a fraction of the baryonic matter budget. Hydrodynamical simulations predict that the missing baryons reside in the vast filamentary structures of the cosmic web as a highly diffuse, warm-hot intergalactic medium (WHIM). Observing the WHIM directly has remained a long-standing challenge due to its typical temperature. In this study, we report the first detection of spatial cross-correlations between the dispersion measures (DMs) of fast radio bursts (FRBs) from the second CHIME/FRB catalog and the thermal Sunyaev-Zel'dovich (tSZ) Compton-$y$ map from the Planck satellite. By masking virialized galaxy clusters to isolate the diffuse signal, we find a positive correlation with a probability $>99.77\%$ between FRBs and tSZ maps. Our joint parameter inference constrains the fraction of cosmic baryons in the WHIM to be $f_{\rm WHIM}=0.48$ with a $68\%$ confidence interval of $0.27<f_{\rm WHIM}<0.61$, anchored at a mean WHIM temperature of $2.4 \times 10^6\ {\rm K}$. More rigorous masking strategies confirm the signal originates from the WHIM instead of galaxy clusters. Our result demonstrates that the missing baryons are residing in the diffuse gas within the cosmic web, closing the cosmic baryon budget in the local Universe.
