论文标题

研究地面CMB观察中大气污染过滤器的研究

Study on the filters of atmospheric contamination in ground based CMB observation

论文作者

Wu, Yi-Wen, Li, SiYu, Liu, Yang, Zhang, Zirui, Liu, Hao, Li, Hong

论文摘要

大气是基于地面宇宙微波背景(CMB)观测值中最重要的污染源之一。在本文中,我们研究了三种过滤器,即多项式过滤器,高通滤波器和维纳尔滤波器,以研究它们消除大气噪声的能力,以及通过CMB实验的端到端模拟对数据分析过程的影响。我们通过分析数据的不同组件的响应(包括信号和噪声)来跟踪它们的性能。在时间域中,计算表明高通滤波器具有最小的均方根误差,可以达到高滤波效率,然后是Wiener滤波器和多项式滤波器。然后,我们使用过滤的时间排序数据(TOD)执行地图制作,以追踪滤波器对地图域的效果,结果表明,多项式过滤器在低频时给出了高噪声残留,这会导致在地图制作过程中的地图域中的小尺度泄漏,而高通滤波器和Wiener滤光片没有大量泄漏。然后,我们估计残留噪声的角功率光谱以及用于比较功率光谱域中滤波器效应的输入信号的角度谱。最后,我们估计过滤器校正的功率谱的标准偏差,以比较不同过滤器的效果,结果表明,在低噪声水平下,这三个过滤器在中和小尺度上给出了几乎可比的标准偏差,但是在高噪声水平上,多项式滤波器的标准偏差明显更大。这些研究可用于减少未来基于地面的CMB数据处理中的大气噪声。

The atmosphere is one of the most important contamination sources in the ground-based Cosmic Microwave Background (CMB) observations. In this paper, we study three kinds of filters, which are polynomial filter, high-pass filter, and Wiener filter, to investigate their ability for removing atmospheric noise, as well as their impact on the data analysis process through the end-to-end simulations of CMB experiment. We track their performance by analyzing the response of different components of the data, including both signals and noise. In the time domain, the calculation shows that the high-pass filter has the smallest root mean square error and can achieve high filtering efficiency, followed by the Wiener filter and polynomial filter. We then perform map-making with the filtered time ordered data (TOD) to trace the effects from filters on the map domain, and the results show that the polynomial filter gives high noise residual at low frequency, which gives rise to serious leakage to small scales in map domain during the map-making process, while the high-pass filter and Wiener filter do not have such significant leakage. Then we estimate the angular power spectra of residual noise, as well as those of the input signal for comparing the filter effects in the power spectra domain. Finally, we estimate the standard deviation of the filter corrected power spectra to compare the effects from different filters, and the results show that, at low noise level, the three filters give almost comparable standard deviations on the medium and small scales, but at high noise level, the standard deviation of the polynomial filter is significantly larger. These studies can be used for the reduction of atmospheric noise in future ground-based CMB data processing.

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