论文标题
从宇宙黎明的21厘米信号模拟中的红移空间变形
Redshift-space distortions in simulations of the 21-cm signal from the cosmic dawn
论文作者
论文摘要
来自宇宙黎明(CD)的21 cm信号可能包含较大的波动,最极端的天体物理模型即将被无线电干涉仪的观察结果排除。因此,至关重要的是,我们不仅要理解管理该信号的天体物理过程,而且了解影响信号本身的其他固有过程,尤其是视线效果。使用我们的一套完全数值的辐射转移模拟,我们研究了从其中一个过程中的CD的红移21厘米的影响,即红移空间畸变(RSD)。当添加RSD时,功率谱的产生提升使我们的模型在所有红移中都可以检测到信号,这进一步增强了希望CD的功率光谱测量的希望。 RSD在CD的开头和末端导致信号的各向异性,但在X射线加热进行时不会。然而,RSD的包含降低了通过偏度和峰度测得的不均匀X射线加热的不均匀X射线加热的可检测性。另一方面,通过我们所有模拟的模拟观察,其中包括望远镜噪声,对应于1000 h的观察,并显示了平方公里阵列望远镜,表明我们可能能够为所考虑的所有加热模型对CD进行图像,并建议RSD急剧增强来自不均匀的Ly-$ ly-$α$。
The 21-cm signal from the Cosmic Dawn (CD) is likely to contain large fluctuations, with the most extreme astrophysical models on the verge of being ruled out by observations from radio interferometers. It is therefore vital that we understand not only the astrophysical processes governing this signal, but also other inherent processes impacting the signal itself, and in particular line-of-sight effects. Using our suite of fully numerical radiative transfer simulations, we investigate the impact on the redshifted 21-cm from the CD from one of these processes, namely the redshift-space distortions (RSDs). When RSDs are added, the resulting boost to the power spectra makes the signal more detectable for our models at all redshifts, further strengthening hopes that a power spectra measurement of the CD will be possible. RSDs lead to anisotropy in the signal at the beginning and end of the CD, but not while X-ray heating is underway. The inclusion of RSDs, however, decreases detectability of the non-Gaussianity of fluctuations from inhomogeneous X-ray heating measured by the skewness and kurtosis. On the other hand, mock observations created from all our simulations that include telescope noise corresponding to 1000 h observation with the Square Kilometre Array telescope show that we may be able image the CD for all heating models considered and suggest RSDs dramatically boost fluctuations coming from the inhomogeneous Ly-$α$ background.