色度优化的天线设计与贝叶斯前景验证用于CANTAR全球21厘米实验
Chromaticity-Optimized Antenna Design and Bayesian Foreground Validation for the CANTAR Global 21 cm Experiment
AI总结：
CANTAR通过优化天线设计和贝叶斯验证，提升全球21厘米信号检测的前景建模与系统误差控制。
摘要：
检测来自再电离时期的全球21厘米信号仍然是一个主要的观测挑战，因为存在明亮的前景和仪器系统误差。作为哥伦比亚南极21厘米吸收期间再电离（CANTAR）计划的一部分，我们提出了一个模拟和分析框架，用于评估天线色度，优化仪器设计，并评估全球21厘米实验的选址适宜性。使用频率依赖的束模型和Haslam基于的天空地图，我们计算了EDGES刀片偶极子和一组通过粒子群优化优化的偶极子和新型单极子天线的动态光谱。优化的设计在70-120 MHz范围内相比EDGES表现出改进的频谱平滑性。我们还评估了纬度依赖的天空亮度，并确定中纬度地区（-40°至+5°）为前景抑制的最佳选址。我们应用贝叶斯推断与后验预测模型验证来处理公开发布的EDGES数据，评估统计一致性而非假设检验或模型比较。我们发现，当排除21厘米吸收特征时，物理驱动的前景和电离层模型才与数据在统计上一致。从经过验证的后验中，我们生成了一组经过统计验证的前景修正，用于束-天空模拟。这些结果支持CANTAR的两阶段策略：南极部署用于校准和测试，以及未来在中纬度地区的科学操作。我们的框架提供了一条经过验证的路径，用于全球21厘米信号检测的稳健前景建模、天线设计和系统误差控制。
英文摘要：
Detecting the global 21 cm signal from the epoch of reionization remains a major observational challenge due to bright foregrounds and instrumental systematics. As part of the Colombian Antarctic Telescopes for 21 cm Absorption during Reionization (CANTAR) initiative, we present a simulation and analysis framework to evaluate antenna chromaticity, optimize instrument design, and assess site suitability for global 21 cm experiments. Using frequency-dependent beam models and Haslam-based sky maps, we compute dynamic spectra for the EDGES blade dipole and a set of dipole and novel monopole antennas optimized via particle swarm optimization. The optimized designs exhibit improved spectral smoothness compared to EDGES, particularly in the 70-120 MHz range. We also evaluate latitude-dependent sky brightness and identify mid-latitude sites (-40° to +5°) as optimal for foreground suppression. We apply Bayesian inference together with posterior predictive model validation to the publicly released EDGES data, assessing statistical consistency rather than hypothesis testing or model comparison. We find that physically motivated foreground and ionospheric models are statistically consistent with the data only when a 21 cm absorption feature is excluded. From the validated posterior, we generate a statistically validated ensemble of foreground corrections for use in beam-sky simulations. These results support a two-phase strategy for CANTAR: Antarctic deployments for calibration and testing, and future science operations at mid-latitude sites. Our framework provides a validated path toward robust foreground modeling, antenna design, and systematics control for global 21 cm signal detection.
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