Detecting the power spectrum turnover with H i intensity mapping
Detecting the power spectrum turnover with H i intensity mapping
复制标题
使用 Hi 强度映射检测功率谱转换
DOI：
10.1093/mnras/stac576
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发表时间：
2022
影响因子：
4.8
通讯作者：
Cunnington S
中科院分区：
文献类型：
--
作者：
Cunnington S
探路者强度测绘（IM）调查的目标将是探测中性氢（${{\rm H}\， \小{\rm I}}$）功率谱中的特征，这些特征可以作为宇宙信号的确凿证据。在${{\rm H}\、\小{\rm I}}$ IM自相关的预期尺度上观察这些特征，其中来自系统学的贡献是不确定的，将提供更有说服力的宇宙学探测。我们演示了如何使用${{\rm H}}， \小{\rm I}}$ IM来检测周转率，即超大尺度下功率谱的峰值。我们发现，使用超高频的MeerKAT 4000survey能够检测到3.1σ的周转率，相对于没有周转率的零模型功率谱。这将超过目前光学和近红外星系调查的能力。MeerKAT波段的探测显著性降至~ 1σ，但平方公里阵列天文台（SKAO）的探测显著性可以达到~ 13σ，这应该很容易超越未来类似第四阶段光谱星系调查的限制。我们还提出了一种新的独立于模型的方法来约束精确周转率（k0），我们对超高频波段模拟数据的测试达到了10%的精度。当使用完整的SKAO时，这一比例提高到2.4%。我们通过使用传递函数证明了结果如何对前景污染具有鲁棒性，即使在构建过程中假设了不正确的宇宙学。考虑到周转率与物质辐射相等的视界尺度有关，一个足够精确的k0约束为一种新的宇宙学探测提供了可能性。因此，我们提出了一种潜在的方法来构建一个基于标准尺子的距离测量，独立于声视界，使用在${{\rm H}\， \小{\rm I}}$功率谱中的翻转位置。
A goal for pathfinder intensity mapping (IM) surveys will be detecting features in the neutral hydrogen (${{\rm H}\, \small {\rm I}}$) power spectrum, which serve as conclusive evidence of cosmological signals. Observing such features at the expected scales in ${{\rm H}\, \small {\rm I}}$ IM autocorrelations, where contribution from systematics is uncertain, will provide a more convincing cosmological detection. We demonstrate how the turnover, i.e. the peak of the power spectrum at ultra-large scales, can be detected with ${{\rm H}\, \small {\rm I}}$ IM. We find that a MeerKAT 4000survey using theUHFband is capable of a 3.1σ detection of the turnover, relative to a null model power spectrum with no turnover. This should exceed what is capable by current galaxy surveys in optical and near-infrared. The detection significance falls to ∼1σ in MeerKAT’sLband but can reach ∼13σ with the Square Kilometre Array Observatory (SKAO), which should easily surpass the constraintsno from future Stage-IV-like spectroscopic galaxy surveys. We also propose a new model-independent methodology for constraining the precise turnover scale (k0) and our tests onUHF-band simulated data achieved a precision of 10 per cent. This improved to 2.4 per cent when using the full SKAO. We demonstrate how the results are robust to foreground contamination by using transfer functions, even when an incorrect cosmology has been assumed in their construction. Given that the turnover is related to the horizon scale at matter–radiation equality, a sufficiently precise constraint ofk0presents the possibility for a novel probe of cosmology. We therefore present a potential methodology for constructing a standard-ruler-based distance measurement, independent of the sound horizon, using the turnover location in the ${{\rm H}\, \small {\rm I}}$ power spectrum.