论文标题
21cm的自旋 - 温度依赖性-LAE互相关
The spin-temperature dependence of the 21cm -- LAE cross-correlation
论文作者
论文摘要
与已知宇宙信号的互相关21cm将是第一个21cm检测的宇宙起源的宝贵证明。作为一些最广泛的领域，包括数千个具有相当知名的红移的来源，窄带Lyman Alpha Emitter（LAE）调查是这种互相关的显而易见的选择。在这里，我们重新审视21厘米 - LAE互相关，放宽了在预热的播层间培养基（IGM）中发生回离的常见假设。使用平方公里阵列的规格和郊区超级CAM，我们提出了21厘米的新预测-LAE互相关功能在$ z \ sim7 $中。我们采样了平均IgM中性分数和自旋温度的宽参数空间（$ \ bar {x} _ {\ rm {hi}} $，$ \ bar {t} _ {\ rm s} $）。互相关的符号大致遵循21厘米信号的符号：周围LAE的电离区域对应于21cm信号中的相对热点，而中性IgM比CMB冷时，当中性IgM比CMB热时，相对冷点。在宇宙HII区域的增加之后，互相关函数的幅度通常会随着$ \ bar {x} _ {\ rm {hi}} $的增加而增加。与21cm一样，当IgM比CMB冷时，最强的交叉信号发生，在中性区域和主持LAE的电离区域之间提供了较大的对比度。我们还改变了电离的拓扑结构和X射线加热时期。在电离上半年期间的互相关对这些拓扑敏感，因此可以用来限制它们。
Cross-correlating 21cm with known cosmic signals will be invaluable proof of the cosmic origin of the first 21cm detections. As some of the widest fields available, comprising thousands of sources with reasonably known redshifts, narrow-band Lyman alpha emitter (LAE) surveys are an obvious choice for such cross-correlation. Here we revisit the 21cm -- LAE cross-correlation, relaxing the common assumption of reionization occurring in a pre-heated intergalactic medium (IGM). Using specifications from the Square Kilometre Array and the Subary Hyper Supreme-Cam, we present new forecasts of the 21cm -- LAE cross-correlation function at $z\sim7$. We sample a broad parameter space of the mean IGM neutral fraction and spin temperature, ($\bar{x}_{\rm{HI}}$, $\bar{T}_{\rm S}$). The sign of the cross-correlation roughly follows the sign of the 21cm signal: ionized regions which surround LAEs correspond to relative hot spots in the 21cm signal when the neutral IGM is colder than the CMB, and relative cold spots when the neutral IGM is hotter than the CMB. The amplitude of the cross-correlation function generally increases with increasing $\bar{x}_{\rm{HI}}$, following the increasing bias of the cosmic HII regions. As is the case for 21cm, the strongest cross signal occurs when the IGM is colder than the CMB, providing a large contrast between the neutral regions and the ionized regions which host LAEs. We also vary the topology of reionization and the epoch of X-ray heating. The cross-correlation during the first half of reionization is sensitive to these topologies, and could thus be used to constrain them.
