External calibrator in global signal experiment for detection of the epoch of reionization

• 作者: Yan Huang Xiang-Ping Wu Quan Guo Qian Zheng Bi-Ying Li Huan-Yuan Shan Ke-Jia Lee Hai-Guang Xu
• 来源期刊: 天文和天体物理学研究
• 年，卷（期）: 2021,（10）
• 所属期刊栏目: Research Papers
• 页码范围: 17-26
• 页数: 10页
• 语种: 英文
• DOI: 10.1088/1674-4527/21/10/243

摘要

We present a conceptual design study of external calibrators in the 21 cm experiment towards detecting the globally averaged radiation of the epoch of reionization(EoR).Employment of external calibrator instead of internal calibrator commonly used in current EoR experiments allows removing instrumental effects such as beam pattern,receiver gain and instability of the system if the conventional three-position switch measurements are implemented in a short time interval.Furthermore,in the new design the antenna system is placed in an underground anechoic chamber with an open/closing ceiling to maximally reduce the environmental effect such as RFI and ground radiation/reflection.It appears that three of the four external calibrators proposed in this paper,including two indoor artificial transmitters and one outdoor celestial radiation(the Galactic polarization),fail to meet our purpose.Diurnal motion of the Galactic diffuse emission turns out to be the most probable source as an external calibrator,for which we have discussed the observational strategy and the algorithm of extracting the EoR signal.