LIMFAST. V. 利用21厘米信号与测光星系巡天的协同效应探测再电离
LIMFAST. V. Probing Reionization with the Synergy Between 21 cm and Photometric Galaxy Surveys
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中文总结 AI 辅助
本文提出利用21厘米信号平方与测光星系互相关的高阶统计量，克服红移精度限制，结合SKA-Low和罗曼巡天数据，在10平方度重叠区域实现再电离纪元物理参数的高显著性约束。
中文摘要 AI 辅助
将星系际中性氢的21厘米信号与星系分布进行互相关，是探测再电离纪元及其驱动物理机制的有力工具。虽然即将开展的SKA-Low射电望远镜和罗曼太空望远镜巡天为此测量提供了理想的协同机会，但21厘米数据的前景减除要求星系具有极高的红移精度，这实际上排除了丰富的测光选出的莱曼断裂星系（LBG）样本，其典型红移不确定度为$\sigma_z \gtrsim 0.1$。我们利用前景减除后21厘米信号的平方统计量来克服这一挑战。对滤波后的21厘米信号进行平方运算，可将幸存的高$k_\parallel$模式耦合到低$k_\parallel$涨落中，从而可被测光LBG巡天探测到。即使直接互相关被强烈抑制，这种高阶互相关统计量仍然可测。利用\texttt{LIMFAST}代码在$6 \lesssim z \lesssim 10$范围内模拟的LBG--21\\,cm$^2$互相关信号，应用Fisher矩阵分析，我们研究了结合SKA-Low 21厘米测量和罗曼测光星系样本约束再电离纪元物理的前景。对于覆盖10\\,deg$^2$的重叠巡天区域，我们发现LBG--21\\,cm$^2$互相关在再电离纪元的大部分时期均可通过1000小时SKA-Low积分（带宽15\\,MHz）和高纬度宽视场巡天（HLWAS）的罗曼测光星系样本（极限星等$m_\mathrm{AB,lim}=27$，测光红移不确定度$\sigma_z \sim 0.1$--0.3）以高显著性探测到。大尺度互功率谱的特征性符号演化——主要由（但并非完全由）演化的中性氢比例驱动——为约束控制星系际介质电离和热历史的物理参数提供了强有力的限制。
英文摘要
Cross-correlating the 21\,cm signal from intergalactic neutral hydrogen with the galaxy distribution is a powerful probe of the Epoch of Reionization and the physical mechanisms driving it. While upcoming surveys with the SKA-Low radio telescope and the Roman Space Telescope offer ideal synergies for this measurement, foreground mitigation of 21\,cm data requires exquisite redshift precision of galaxies, effectively excluding the rich photometrically selected samples of Lyman-break galaxies (LBGs) with typical redshift uncertainties $σ_z \gtrsim 0.1$. We overcome this challenge using a squared statistic of the foreground-cleaned 21\,cm signal. Squaring the filtered 21\,cm signal couples surviving high $k_\parallel$ modes into low $k_\parallel$ fluctuations accessible to photometric LBG surveys. This higher-order cross-correlation statistic remains measurable even when direct cross-correlations are strongly suppressed. Applying Fisher matrix analysis to this LBG--21\,cm$^2$ cross-correlation signal simulated by the \texttt{LIMFAST} code over $6 \lesssim z \lesssim 10$, we investigate the prospects for constraining EoR physics combining SKA-Low 21\,cm measurements and Roman photometric galaxy samples. For an overlapping survey area covering 10\,deg$^2$, we find that the LBG--21\,cm$^2$ cross-correlation is detectable at high significance across much of the EoR through 1000\,hours of SKA-Low integration with 15\,MHz bandwidth and a Roman photometric galaxy sample from the High-Latitude Wide-Area Survey (HLWAS) reaching $m_\mathrm{AB,lim}=27$ and photo-$z$ uncertainties of $σ_z \sim 0.1$--0.3. The characteristic sign evolution of the large-scale cross-power spectrum---driven primarily, though not exclusively, by the evolving neutral fraction---provides strong constraints on the physical parameters governing the ionization and thermal history of the IGM.
发表机构
- Northwestern University（西北大学）
- University of Pennsylvania（宾夕法尼亚大学）
- California Institute of Technology（加州理工学院）
- Jet Propulsion Laboratory, California Institute of Technology（加州理工学院喷气推进实验室）
- University of California, Los Angeles（加利福尼亚大学洛杉矶分校）
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