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Accepted manuscript

Forecast Measurement of the 21 cm Global Spectrum from Lunar Orbit with the Vari-Zeroth-Order Polynomial (VZOP) Method

Published online by Cambridge University Press:  26 March 2025

Tianyang Liu Open the ORCID record for Tianyang Liu [Opens in a new window] ,
Jiajun Zhang Open the ORCID record for Jiajun Zhang [Opens in a new window] ,
Yuan Shi Open the ORCID record for Yuan Shi [Opens in a new window] ,
Junhua Gu Open the ORCID record for Junhua Gu [Opens in a new window] ,
Quan Guo Open the ORCID record for Quan Guo [Opens in a new window] ,
Yidong Xu Open the ORCID record for Yidong Xu [Opens in a new window] ,
Furen Deng Open the ORCID record for Furen Deng [Opens in a new window] ,
Fengquan Wu Open the ORCID record for Fengquan Wu [Opens in a new window] ,
Yanping Cong Open the ORCID record for Yanping Cong [Opens in a new window]  and
Xuelei Chen Open the ORCID record for Xuelei Chen [Opens in a new window]
Tianyang Liu
Affiliation:
Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030, China School of Astronomy and Space Science, University of Chinese Academy of Sciences, Beijing 100049, China
Jiajun Zhang*
Affiliation:
Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030, China
Yuan Shi
Affiliation:
Department of Astronomy, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China Key Laboratory for Particle Astrophysics and Cosmology (MOE)/Shanghai Key Laboratory for Particle Physics and Cosmology, China
Junhua Gu*
Affiliation:
National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100101, China
Quan Guo*
Affiliation:
Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030, China
Yidong Xu
Affiliation:
National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100101, China Key Laboratory of Radio Astronomy and Technology, Chinese Academy of Sciences, A20 Datun Road, Chaoyang District, Beijing, 100101, P. R. China
Furen Deng
Affiliation:
School of Astronomy and Space Science, University of Chinese Academy of Sciences, Beijing 100049, China National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100101, China
Fengquan Wu
Affiliation:
National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100101, China
Yanping Cong
Affiliation:
Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030, China
Xuelei Chen
Affiliation:
School of Astronomy and Space Science, University of Chinese Academy of Sciences, Beijing 100049, China National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100101, China Department of Physics, College of Sciences, Northeastern University, Shenyang 110819, China Center for High Energy Physics, Peking University, Beijing 100871, China
*
Author for correspondence: Jiajun Zhang & Junhua Gu & Quan Guo, Email: jjzhang@shao.ac.cn, jhgu@nao.cas.cn, guoquan@shao.ac.cn.
Author for correspondence: Jiajun Zhang & Junhua Gu & Quan Guo, Email: jjzhang@shao.ac.cn, jhgu@nao.cas.cn, guoquan@shao.ac.cn.
Author for correspondence: Jiajun Zhang & Junhua Gu & Quan Guo, Email: jjzhang@shao.ac.cn, jhgu@nao.cas.cn, guoquan@shao.ac.cn.
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Abstract

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The cosmic 21 cm signal serves as a crucial probe for studying the evolutionary history of the Universe. However, detecting the 21 cm signal poses significant challenges due to its extremely faint nature. To mitigate the interference from the Earth’s radio frequency interference (RFI), the ground and the ionospheric effects, the Discovering the Sky at the Longest Wavelength (DSL) project will deploy a constellation of satellites in Lunar orbit, with its high-frequency daughter satellite tasked with detecting the global 21 cm signal from cosmic dawn and reionization era (CD/EoR).We intend to employ the Vari-Zeroth-Order Polynomial (VZOP) for foreground fitting and subtracting. We have studied the effect of thermal noise, thermal radiation from the Moon, the Lunar reflection, anisotropic frequency-dependent beam, inaccurate antenna beam pattern, and RFI contamination. We discovered that the RFI contamination can significantly affect the fitting process and thus prevent us from detecting the signal. Therefore, experimenting on the far side of the moon is crucial. We also discovered that using VZOP together with DSL, after 1080 orbits around the Moon, which takes about 103 days, we can successfully detect the CD/EoR 21 cm signal.

Keywords

dark ages, reionization, first starsmethods: statisticalspace vehicles: instruments
Type
Research Article
Information
Publications of the Astronomical Society of Australia , Accepted manuscript , pp. 1 - 20
Creative Commons
Creative Common License - CCCreative Common License - BYCreative Common License - NCCreative Common License - ND
This is an Open Access article, distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives licence (https://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is unaltered and is properly cited. Written permission from Cambridge University Press is required for commercial re-use or to create a derivative work.
Copyright
© The Author(s), 2025. Published by Cambridge University Press on behalf of Astronomical Society of Australia