论文标题

前景清除和21厘米信号估计:比较宾果望远镜的不同盲方法

Foreground removal and 21 cm signal estimates: comparing different blind methods for the BINGO Telescope

论文作者

Marins, Alessandro, Abdalla, Filipe B., Fornazier, Karin S. F., Abdalla, Elcio, Assis, Luiz H. F., Remazeilles, Mathieu, Wuensche, Carlos Alexandre, Barosi, Luciano, Queiroz, Amilcar R., Villela, Thyrso, Wang, Bin, Feng, Chang, Landim, Ricardo, Liccardo, Vincenzo, Novaes, Camila P., Santos, Larissa, Santos, Marcelo V. dos, Zhang, Jiajun

论文摘要

宾果游戏将通过21 cm线信号观察氢分布,通过在980和1260 MHz之间的层流分析中漂移扫描映射,旨在使用\ emph {baryon ocoustic振荡}分析暗能量。在相同的频率范围内,还有其他几个不需要的信号以及仪器噪声,污染了目标信号。重建信号有许多组件分离方法。在这里,我们仅使用了三种盲方法(FastICA,GNILC和GMCA),这些方法探索了不同的方法来估计前景与天空中观察到的信号的贡献。随后,我们从混合噪声中估计21 cm信号。我们还分析了不同数量的模拟如何影响估计的质量,以及构图对角功率谱对与噪声混合的21 cm估算21 cm的影响。对于当前模拟中考虑的宾果天空范围和灵敏度以及前景模型,我们发现前景子空间的有效尺寸导致最佳结果等于三个,由非物理模板组成。在管道配置的这一刻,使用50或400个模拟在统计上是等效的。还可以将多极端的数量减少一半,以加快过程并保持结果质量。当我们假设400个实现时,所有三种算法都用于执行前景去除,均产生了统计上等效的结果,用于估计21cm信号,而GMCA和FastICA的混合矩阵尺寸等于三。但是,关于宾果管线的这一阶段的计算成本,FastICA比其他算法快。当可以使用时间订购的数据和制图制作时,需要进行新的比较。

BINGO will observe hydrogen distribution by means of the 21 cm line signal by drift-scan mapping through a tomographic analysis called \emph{Intensity Mapping} (IM) between 980 and 1260 MHz which aims at analyzing Dark Energy using \emph{Baryon Acoustic Oscillations}. In the same frequency range, there are several other unwanted signals as well as instrumental noise, contaminating the target signal. There are many component separation methods to reconstruct signals. Here, we used just three blind methods (FastICA, GNILC and GMCA), which explore different ways to estimate foregrounds' contribution from observed signals from the sky. Subsequently, we estimate 21 cm signal from its mixing with noise. We also analyzed how different number of simulations affect the quality of the estimation, as well as the effect of the binning on angular power spectrum to estimate 21 cm from the mixing with noise. For the BINGO sky range and sensitivity and the foreground model considered in the current simulation, we find that the effective dimension of the foreground subspace leading to best results is equal to three, composed of non-physical templates. At this moment of the pipeline configuration, using 50 or 400 simulations is statistically equivalent. It is also possible to reduce the number of multipoles by half to speed up the process and maintain the quality of results. All three algorithms used to perform foreground removal yielded statistically equivalent results for estimating the 21cm signal when we assume 400 realizations and GMCA and FastICA's mixing matrix dimensions equal to three. However, concerning computational cost in this stage of the BINGO pipeline, FastICA is faster than other algorithms. A new comparison will be necessary when the time-ordered-data and map-making are available.

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