The initial conditions for the density perturbations in the early Universe, which dictate the large-scale structure and distribution of galaxies we see today, are set during inflation. Measurements of primordial non-Gaussianity are crucial for distinguishing between different inflationary models. Current measurements of the matter power spectrum from the cosmic microwave background only constrain this on scales up to k ∼ 0.1 Mpc−1. Reaching smaller angular scales (higher values of k) can provide new constraints on non-Gaussianity. A powerful way to do this is by measuring the HI matter power spectrum at z≳30. In this paper, we investigate what values of k can be reached for the Low-Frequency Array (LOFAR), which can achieve ≲1″ resolution at approximately 50 MHz. Combining this with a technique to isolate the spectrally smooth foregrounds to a wedge in k∥–k⊥ space, we demonstrate what values of k we can feasibly reach within observational constraints. We find that LOFAR is approximately five orders of magnitude away from the desired sensitivity, for 10 years of integration time. This article is part of a discussion meeting issue ‘Astronomy from the Moon: the next decades’.

中文翻译：

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用低频成像达到小尺度：在黑暗时代的应用

早期宇宙中密度扰动的初始条件决定了我们今天看到的星系的大尺度结构和分布，是在暴胀期间设定的。原始非高斯性的测量对于区分不同的通货膨胀模型至关重要。当前对来自宇宙微波背景的物质功率谱的测量仅将其限制在 k ∼ 0.1 Mpc-1 的尺度上。达到更小的角度尺度（更高的 k 值）可以为非高斯性提供新的约束。一种有效的方法是测量 z≳30 处的 HI 物质功率谱。在本文中，我们研究了低频阵列 (LOFAR) 可以达到的 k 值，它可以在大约 50 MHz 下实现≲1″的分辨率。将此与将光谱平滑前景隔离到 k∥–k⊥ 空间中的楔形的技术相结合，我们证明了我们可以在观察约束内可行地达到哪些 k 值。我们发现，对于 10 年的积分时间，LOFAR 与所需的灵敏度相差大约五个数量级。这篇文章是讨论会问题“月球天文学：未来几十年”的一部分。