Studying infall in infrared dark clouds with multiple HCO transitions  

作　　者：Jin-Jin Xie Jing-Wen Wu Gary A.Fuller Nicolas Peretto Zhi-Yuan Ren Long-Fei Chen Yao-Ting Yan Guo-Dong Li Yan Duan Ji-Feng Xia Yong-Xiong Wang Di Li 谢津津;吴京文;Gary A.Fuller;Nicolas Peretto;任致远;陈龙飞;闫耀庭;李国栋;段言;夏季风;王永雄;李菂(National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China;University of Chinese Academy of Sciences,Beijing 100049,China;Jodrell Bank Centre for Astrophysics,Department of Physics&Astronomy,The University of Manchester,Manchester M139PL,United Kingdom;I.Physikalisches Institut,University of Cologne,Zlilpicher Str.77,50937 Koln,Germany;NAOC-UKZN Computational Astrophysics Centre,University of KwaZulu-Natal,Durban 4000,South Africa;School of Physics&Astronomy,Cardiff University,Queen's Building,The Parade,Cardiff,CF243AA,United Kingdom;Max-Planck-Institut fur Radioastronomie,Auf dem Hiigel 69,53121 Bonn,Germany)

机构地区：[1]National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China [2]University of Chinese Academy of Sciences,Beijing 100049,China [3]Jodrell Bank Centre for Astrophysics,Department of Physics&Astronomy,The University of Manchester,Manchester M139PL,United Kingdom [4]I.Physikalisches Institut,University of Cologne,Zlilpicher Str.77,50937 Koln,Germany [5]NAOC-UKZN Computational Astrophysics Centre,University of KwaZulu-Natal,Durban 4000,South Africa [6]School of Physics&Astronomy,Cardiff University,Queen's Building,The Parade,Cardiff,CF243AA,United Kingdom [7]Max-Planck-Institut fur Radioastronomie,Auf dem Hiigel 69,53121 Bonn,Germany

出　　处：《Research in Astronomy and Astrophysics》2021年第8期253-268,共16页天文和天体物理学研究（英文版）

基　　金：supported by the National Natural Science Foundation of China (NSFC,Grant Nos.11988101,11725313,and 11721303);the International Partnership Program of Chinese Academy of Sciences (Grant No.114A11KYSB20160008);the National Key R&D Program of China (No.2016YFA0400702)。

摘　　要：We investigate the infall properties in a sample of 11 infrared dark clouds(IRDCs) showing blue-asymmetry signatures in HCO^(+)J=1-0 line profiles.We used JCMT to conduct mapping observations in HCO^(+)J=4-3 as well as single-point observations in HCO+J=3-2,towards 23 clumps in these IRDCs.We applied the HILL model to fit these observations and derived infall velocities in the range of 0.5-2.7 km s^(-1),with a median value of 1.0 km s^(-1),and obtained mass accretion rates of 0.5-14 ×10^(-3) Mo yr^(-1).These values are comparable to those found in massive star forming clumps in later evolutionary stages.These IRDC clumps are more likely to form star clusters.HCO^(+)J=3-2 and HCO^(+)J=1-0 were shown to trace infall signatures well in these IRDCs with comparable inferred properties.HCO^(+)J=4-3,on the other hand,exhibits infall signatures only in a few very massive clumps,due to smaller opacities.No obvious correlation for these clumps was found between infall velocity and the NH3/CCS ratio.

关 键 词：stars:formation ISM:clouds star formation:kinematics and dynamics 

分 类 号：P152[天文地球—天文学]