On Measuring the 21 cm Global Spectrum of the Cosmic Dawn with an Interferometer Array
On Measuring the 21 cm Global Spectrum of the Cosmic Dawn with an Interferometer Array
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DOI：
10.3847/1538-4357/acb6fe
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发表时间：
2023-01
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通讯作者：
Xin 欣 Zhang 张;Bin 斌 Yue 岳;Yuan 嫄 Shi 施;Fengquan 锋泉 Wu 吴;X. Chen 陈
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作者：
Xin 欣 Zhang 张;Bin 斌 Yue 岳;Yuan 嫄 Shi 施;Fengquan 锋泉 Wu 吴;X. Chen 陈
我们从理论上研究了从干涉仪阵列测量的vibrium（仅互相关）中恢复全局光谱（Vibrium）以及提取宇宙黎明21 cm信号的可行性。在我们的方法中，全球频谱是通过解决的高次和高阶分量，同时从vibrium测量多达数千个基线。使用该算法，前景和21 cm信号的失真可以在广泛的条件下正确地恢复。我们发现，3D基线分布可以比2D（平面）基线分布具有更好的性能，特别是当缺乏较短的基线时。我们模拟了地面二维和三维阵列配置，以及位于日地L2点的十字形空间阵列，可以通过轨道进动形成三维基线。在所有的模拟中，我们得到了一个很好的恢复全球频谱，并成功地提取了21厘米的信号，与合理的天线数量和观察时间。
We theoretically investigate the recovery of the global spectrum (monopole) from visibilities (cross-correlation only) measured by an interferometer array and the feasibility of extracting the 21 cm signal of the cosmic dawn. In our approach, the global spectrum is obtained by solving the monopole and higher-order components simultaneously from visibilities measured with up to thousands of baselines. Using this algorithm, the monopole of both the foreground and the 21 cm signal can be correctly recovered in a broad range of conditions. We find that a 3D baseline distribution can have much better performance than a 2D (planar) baseline distribution, particularly when there is a lack of shorter baselines. We simulate for ground-based 2D and 3D array configurations, and a cross-shaped space array located at the Sun–Earth L2 point that can form 3D baselines through orbital precession. In all simulations we obtain a good recovered global spectrum, and successfully extract the 21 cm signal from it, with a reasonable number of antennas and observation time.