globalemu : a novel and robust approach for emulating the sky-averaged 21-cm signal from the cosmic dawn and epoch of reionization
globalemu : a novel and robust approach for emulating the sky-averaged 21-cm signal from the cosmic dawn and epoch of reionization
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globalemu：一种新颖而强大的方法，用于模拟来自宇宙黎明和再电离时代的天空平均 21 厘米信号
DOI：
10.1093/mnras/stab2737
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发表时间：
2021
影响因子：
4.8
通讯作者：
Bevins H
中科院分区：
文献类型：
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作者：
Bevins H
用神经网络模拟全球（天空平均）21厘米信号已被证明是物理信号建模的重要工具。在本文中，我们提出了globalemu，全球21厘米信号模拟器，使用红移作为一个字符定义变量旁边的一组天体物理参数来估计信号亮度温度。与物理驱动的数据预处理相结合，这使得仿真器可靠而快速，对网络设计相对不敏感。globalemucan可以在1.3 ms内仿真高分辨率信号，而使用现有的公共最先进的21 cmGEM时，仿真时间为133 ms，提高了102倍。我们说明，与标准的天体物理模型用于训练21厘米GEM，thatglobalemu几乎是准确的两倍，并为一个测试集的1700个信号，我们实现了一个平均均方根误差为2.52 mK的整个频带z = 7-28 [百分之十的预期噪声的无线电实验宇宙氢的分析（REACH）]。这些模型分别由星星形成效率f*、最小维里圆速度Vc、X射线效率fX、宇宙微波背景光学厚度τ、X射线谱能量密度的斜率和低能截止值α和νmin以及电离光子的平均自由程等参数化。globalemu提供了一个灵活的框架，可以轻松地模拟全局信号的更新模拟以及中性分数历史。该模拟器是pip可安装的，可在https://github.com/htjb/globalemu.globalemuwill上获得，并被REACH协作广泛使用。
Emulation of the Global (sky-averaged) 21-cm signal with neural networks has been shown to be an essential tool for physical signal modelling. In this paper, we presentglobalemu, a Global 21-cm signal emulator that uses redshift as a character-defining variable alongside a set of astrophysical parameters to estimate the signal brightness temperature. Combined with physically motivated data pre-processing, this makes for a reliable and fast emulator that is relatively insensitive to the network design.globalemucan emulate a high-resolution signal in 1.3 ms in comparison to 133 ms, a factor of 102 improvement, when using the existing public state-of-the-art21cmGEM. We illustrate, with the standard astrophysical models used to train21cmGEM, thatglobalemuis almost twice as accurate and for a test set of ≈1700 signals we achieve a mean root mean squared error of 2.52 mK across the bandz= 7–28 [≈10 per cent the expected noise of the Radio Experiment for the Analysis of Cosmic Hydrogen (REACH)]. The models are parametrized by the star formation efficiency,f*, minimum virial circular velocity,Vc, X-ray efficiency,fX, cosmic microwave background optical depth, τ, the slope and low energy cut-off of the X-ray spectral energy density, α andνmin, respectively, and the mean free path of ionizing photons,Rmfp.globalemuprovides a flexible framework for easily emulating updated simulations of the Global signal and in addition the neutral fraction history. The emulator is pip installable and available at https://github.com/htjb/globalemu.globalemuwill be used extensively by the REACH collaboration.