FAST Observations of Four Comets to Search for the Molecular Line Emissions between 1.0 and 1.5 GHz Frequencies  

作　　者：Long-Fei Chen Chao-Wei Tsai Jian-Yang Li Bin Yang Di Li Yan Duan Chih-Hao Hsia Zhichen Pan Lei Qian Donghui Quan Xue-Jian Jiang Xiaohu Li Ruining Zhao Pei Zuo 

机构地区：[1]School of Physics and Electronic Science,Guizhou Normal University,Guiyang 550025,China [2]Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing,Guiyang 550025,China [3]Research Center for Astronomical Computing,Zhejiang Laboratory,Hangzhou 311100,China [4]National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China [5]Institute for Frontiers in Astronomy and Astrophysics,Beijing Normal University,Beijing 102206,China [6]Key Laboratory of Radio Astronomy and Technology,Chinese Academy of Sciences,Beijing 100101,China [7]School of Atmospheric Sciences,Sun Yat-sen University,Zhuhai 519082,China [8]Núcleo de Astronomía,Facultad de Ingenieríay Ciencias,Universidad Diego Portales,Chile [9]Department of Astronomy,College of Physics and Electronic Engineering,Qilu Normal University,Jinan 250200,China [10]Department of Electronic and Optical Engineering,Space Engineering University,Beijing 101416,China [11]Laboratory for Space Research,Faculty of Science,The University of Hong Kong,Hong Kong(SAR),China [12]Xinjiang Astronomical Observatory,Chinese Academy of Sciences,Urumqi 830011,China [13]CAS Key Laboratory of Optical Astronomy,National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China [14]School of Astronomy and Space Sciences,University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Research in Astronomy and Astrophysics》2024年第10期130-140,共11页天文和天体物理学研究（英文版）

基　　金：supported by a grant from the National Natural Science Foundation of China(NSFC)No.11988101;by the NSFC grant Nos.11703047,11773041,U2031119,12173052,12173053,12373032,and 11963002;support from the China Postdoctoral Science Foundation grant No.2023M733271;the Foundation of Education Bureau of Guizhou Province,China(grant No.KY(2020)003);supported by the International Partnership Program of the Chinese Academy of Sciences,program No.114A11KYSB20210010;the Youth Innovation Promotion Association of the Chinese Academy of Sciences(ID Nos.2023064,2018075,and Y2022027);the support from the National Key R&D Program of China grant Nos.2022YFC2205202 and 2020SKA0120100;supported by the CAS“Light of West China”Program;the support by the NSFC grant No.12373026。

摘　　要：We used the Five-hundred-meter Aperture Spherical radio Telescope(FAST)to search for the molecular emissions in the L-band between 1.0 and 1.5 GHz toward four comets,C/2020 F3(NEOWISE),C/2020 R4(ATLAS),C/2021 A1(Leonard),and 67P/Churyumov-Gerasimenko during or after their perihelion passages.Thousands of molecular transition lines fall in this low-frequency range,many attributed to complex organic or prebiotic molecules.We conducted a blind search for the possible molecular lines in this frequency range in those comets and could not identify clear signals of molecular emissions in the data.Although several molecules have been detected at high frequencies of greater than100 GHz in comets,our results confirm that it is challenging to detect molecular transitions in the L-band frequency ranges.The non-detection of L-band molecular lines in the cometary environment could rule out the possibility of unusually strong lines,which could be caused by the masers or non-LTE effects.Although the line strengths are predicted to be weak,for FAST,using the ultra-wide bandwidth receiver and improving the radio frequency interference environments would enhance the detectability of those molecular transitions at low frequencies in the future.

关 键 词：ASTROCHEMISTRY ISM:molecules comets:general line:identification 

分 类 号：P111.44[天文地球—天文学] P185.81