A comprehensive Bayesian reanalysis of the SARAS2 data from the epoch of reionization
A comprehensive Bayesian reanalysis of the SARAS2 data from the epoch of reionization
复制标题
对再电离时代 SARAS2 数据进行全面的贝叶斯再分析
DOI：
10.1093/mnras/stac1158
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发表时间：
2022
影响因子：
4.8
通讯作者：
Bevins H
中科院分区：
文献类型：
--
作者：
Bevins H
我们提出了一个贝叶斯再分析的天空平均21厘米的实验数据从SARAS 2使用嵌套采样实现与polychord，光谱平滑前景建模实现与maxsmooth，详细的系统建模和快速信号仿真与globalemu。我们的分析与之前对SARAS 2数据的分析不同，因为我们使用了完整的贝叶斯框架以及对前景和非平滑系统的单独建模。我们使用最新的信号模型，包括莱曼-α和CMB加热参数化的天体物理参数，如星星形成效率，X射线加热效率，最小维里圆周速度的星星形成星系，CMB光学厚度，和低能量截止的X射线光谱能量分布。我们认为模型与多余的无线电背景以上的CMB产生通过无线电发射从早期星系和参数化的无线电生产效率。一个非平滑的系统被识别和建模为一个频率阻尼正弦波引入的电子和独立的天空。后者由天线的总效率调制，并且由数据略微有利。我们考虑三种不同的模型的数据中的噪声。SARAS 2对单个天体物理参数的约束非常弱，但是，我们识别出了不利信号的类别。我们不赞成标准天体物理模型与高莱曼-α通量和弱加热，更有信心不赞成外来模型与高莱曼-α通量，低X射线效率，高射电产生效率的早期星系。
We present a Bayesian re-analysis of the sky-averaged 21-cm experimental data from SARAS2 using nested sampling implemented withpolychord, spectrally smooth foreground modelling implemented withmaxsmooth, detailed systematic modelling and rapid signal emulation withglobalemu. Our analysis differs from previous analysis of the SARAS2 data through the use of a full Bayesian framework and separate modelling of the foreground and non-smooth systematics. We use the most up-to-date signal models, including Lyman-α and CMB heating parametrized by astrophysical parameters such as star formation efficiency, X-ray heating efficiency, minimal virial circular velocity of star forming galaxies, CMB optical depth, and the low energy cutoff of the X-ray spectral energy distribution. We consider models with an excess radio background above the CMB produced via radio emission from early galaxies and parametrized by a radio production efficiency. A non-smooth systematic is identified and modelled as both a frequency damped sinusoid introduced by the electronics and separately from the sky. The latter is modulated by the total efficiency of the antenna and marginally favoured by the data. We consider three different models for the noise in the data. The SARAS2 constraints on individual astrophysical parameters are extremely weak, however, we identify classes of disfavoured signals. We weakly disfavour standard astrophysical models with high Lyman-α fluxes and weak heating and more confidently disfavour exotic models with high Lyman-α fluxes, low X-ray efficiencies, and high radio production efficiencies in early galaxies.