Pilot HI survey of Planck Galactic Cold Clumps with FAST

查看全文 作　　者：[1,2]汤宁宇;[3]左沛;[1,2,4]李菂;Lei [1,2]Qian;Tie [5,6]Liu;Yue-Fang [7]Wu;Marko [1,2]Krco;Meng-Ting [1,2]Liu;You-Ling [1,2]Yue;Yan [1,2]Zhu;Hong-Fei [1,2]Liu;Dong-Jun [1,2]Yu;Jing-Hai [1,2]Sun;Peng [1,2]Jiang;Gao-Feng [1,2]Pan;Hui [1,2]Li;Heng-Qian [1,2]Gan;Rui [1,2]Yao;Shu [1,2]Liu;FAST [1]Collaboration

机构地区：[1]National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China;[2]CAS Key Laboratory of FAST,National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China;[3]Kavli Institute for Astronomy and Astrophysics,Peking University,Beijing 100871,China;[4]School of Astronomy and Space Science,University of Chinese Academy of Sciences,Beijing 100049,China;[5]Shanghai Astronomical Observatory,Chinese Academy of Sciences,Shanghai 200030,China,Shanghai 200030,China;[6]East Asian Observatory,HI 96720,USA;[7]Department of Astronomy,School of Physics,Peking University,Beijing 100871,China

出　　处：《Research in Astronomy and Astrophysics》索引2020年第20卷第5期,共12页

基　　金：supported by the National Key R&D Program of China(2017YFA0402600 and 2016YFA0400702);the National Natural Science Foundation of China(Grant Nos.11988101,11803051,11725313 and 11721303);CAS International Partnership Program(114A11KYSB20160008);CAS“Light of West China”Program;CAS Interdisciplinary Innovation Team and Young Researcher Grant of National Astronomical Observatories;supported in part by the Youth Innovation Promotion Association of CAS(No.2018075) 摘　　要：We present a pilot HI survey of 17 Planck Galactic Cold Clumps(PGCCs)with the Five-hundred-meter Aperture Spherical radio Telescope(FAST).HI Narrow Self-Absorption(HINSA)is an effective method to detect cold HI being mixed with molecular hydrogen H2 and improves our understanding of the atomic to molecular transition in the interstellar medium.HINSA was found in 58%PGCCs that we observed.The column density of HINSA was found to have an intermediate correlation with that of 13CO,following log(N(HINSA))=(0.52±0.26)log(N13CO)+(10±4.1).HI abundance relative to total hydrogen[HI]/[H]has an average value of 4.4×10-3,which is about 2.8 times of the average value of previous HINSA surveys toward molecular clouds.For clouds with total column density NH>5×1020 cm-2,an inverse correlation between HINSA abundance and total hydrogen column density is found,confirming the depletion of cold HI gas during molecular gas formation in more massive clouds.Nonthermal line width of 13CO is about 0-0.5 kms-1 larger than that of HINSA.One possible explanation of narrower non-thermal width of HINSA is that HINSA region is smaller than that of 13CO.Based on an analytic model of H2 formation and H2 dissociation by cosmic ray,we found the cloud ages to be within 106.7-107.0 yr for five sources. 关键词：ISM:clouds ISM:evolution ISM:molecules

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Pilot HI survey of Planck Galactic Cold Clumps with FAST

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