山体对于宇宙低频总功率实验的影响  

Effects of the Surrounding Mountains on the Extraction of Signals from the Global 21 cm Signal Experiment

作　　者：沈廷燕 余赟[2] 顾俊骅[3] 黄滟 郭铨 SHEN Ting-yan;YU Yun;GU Jun-hua;HUANG Yan;GUO Quan(School of Physical and Electronic Sciences,Guizhou Normal University,Guiyang 550001,China;Shanghai Astronomical Observatory,Chinese Academy of Sciences,Shanghai 200030,China;National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100080,China)

机构地区：[1]贵州师范大学,贵阳550001 [2]中国科学院上海天文台,上海200030 [3]中国科学院国家天文台,北京100080

出　　处：《天文学进展》2024年第3期529-550,共22页Progress In Astronomy

基　　金：SKA专项(2020SKA0110100);国家自然科学基金重点项目(12433012)。

摘　　要：该文主要分析实验天线所在周围山体对低频全天总功率实验提取中性氢21cm信号的影响。基于涵盖山体的高度、倾斜角、山体的组成成分及其一致性和山体到天线的距离等多种因素的模型,利用基于矩量法的混合数值模拟算法对山体影响进行一系列的电磁场传播的模拟计算,并进一步分析这些因素对天线增益和中性氢信号提取的影响。研究结果表明,山体的特征,包括其高度、与观测点的距离、倾斜角、构成材质和表面成分的一致性,不仅对天线的增益产生影响,而且会对后续中性氢信号的多项式拟合提取产生影响。当山体相对于天线的视角越小,则对天线增益的影响越小;山体错落排列比规则环状山体对天线增益扰动更大。而对于再电离信号的提取,各向异性的山体成分和山体错落排列都会影响多项式前景扣除的精度,进而干扰再电离信号的提取。In this paper,we examine the influence of the surrounding mountains around the experimental antenna on the extraction of signals in the global 21 cm experiment.The change in antenna gains introduced by varying the height of the mountain,the angle of slope,the composition of the mountain,the consistency of the composition of the mountain,the distance from the mountain to the antenna,and other factors of the model is simulated using the moment hybrid numerical algorithm.We further analyze the impact of these factors on the antenna in obtaining neutral hydrogen signals.The results show that the characteristics of the mountain,including its height,distance from the observation point,inclination angle,composition material,and surface composition consistency,not only affect the antenna gain,but also further affect the polynomial fitting subtraction of the foreground in the experiment.Specifically,for antenna gain,when the mountain height remains unchanged,the farther the mountain is from the antenna,the smaller the effect on antenna gain.

关 键 词：天线增益 山体特征 低频总功率信号 

分 类 号：P161[天文地球—天文学]