论文标题
通过人工神经网络从21cm功率谱从21cm功率谱的HII气泡尺寸分布的估计
Estimation of HII Bubble Size Distribution from 21cm Power Spectrum with Artificial Neural Networks
论文作者
论文摘要
电离氢区域的气泡尺寸分布探测有关在电离期间\ hii \ bubbles的形态的信息。通常，\ hii \气泡尺寸分布可以源自从电离时期的红移21厘米信号的层析成像数据中得出，但是，即使对于即将到来的大型无线电干涉仪阵列，这在观察方面也充满挑战。鉴于这些干涉仪有望准确地测量21 cm功率谱，我们提出了一种基于人工神经网络（ANN）的新方法，以重建从21 cm功率谱的\ hii \ bubble尺寸分布。我们证明，从成像数据中直接测量的具有分数误差$ \ lyseSim 10 \％$，即使在平方英基阵列的灵敏度水平下，从成像数据中直接测量了21 〜cm功率谱的重建。然而，重建在电离模拟中隐含地利用了建模，因此恢复的\ hii \ bubble尺寸分布并不是功率谱的独立摘要统计量，仅应作为理解\ hii \ hii \ bubble的指标及其进化。
The bubble size distribution of ionized hydrogen regions probes the information about the morphology of \HII\ bubbles during the reionization. Conventionally, the \HII\ bubble size distribution can be derived from the tomographic imaging data of the redshifted 21~cm signal from the epoch of reionization, which, however, is observationally challenging even for the upcoming large radio interferometer arrays. Given that these interferometers promise to measure the 21~cm power spectrum accurately, we propose a new method, which is based on the artificial neural networks (ANN), to reconstruct the \HII\ bubble size distribution from the 21~cm power spectrum. We demonstrate that the reconstruction from the 21~cm power spectrum can be almost as accurate as directly measured from the imaging data with the fractional error $\lesssim 10\%$, even with thermal noise at the sensitivity level of the Square Kilometre Array. Nevertheless, the reconstruction implicitly exploits the modelling in reionization simulations, and hence the recovered \HII\ bubble size distribution is not an independent summary statistic from the power spectrum, and should be used only as the indicator for understanding \HII\ bubble morphology and its evolution.
