A statistical study towards high-mass BGPS clumps with the MALT90 survey

• Published in: Research in astronomy and astrophysics 2018, Vol.18 (1), p.31-58
• Main Authors: Liu, Xiao-Lan, Xu, Jin-Long, Ning, Chang-Chun, Zhang, Chuan-Peng, Liu, Xiao-Tao
• Format: Article
• Language: English
• Subjects: Astrochemistry; Astronomy; Biological evolution; Clumps; ISM: abundance; ISM: kinematics and dynamics; ISM: molecules; Linear functions; Polls & surveys; radio lines: ISM; stars: formation; Tracers; 统计调查; HNCO; 天文学; HCO; HCN; SiO; 分子; 稠密
• ISSN: 1674-4527; 2397-6209
• DOI: 10.1088/1674-4527/18/1/4

In this work,we perform a statistical investigation towards 50 high-mass clumps using data from the Bolocam Galactic Plane Survey（BGPS）and Millimetre Astronomy Legacy Team 90-GHz survey（MALT90）.Eleven dense molecular lines（N2H^＋（1–0）,HNC（1–0）,HCO^＋（1–0）,HCN（1–0）,HN^（13）C（1–0）,H^（13）CO^＋（1–0）,C2H（1–0）,HC3N（10–9）,SiO（2–1）,^（13）CS（2–1）and HNCO（4（4,0）-3（0,3）））are detected.N2H^＋ and HNC are shown to be good tracers for clumps in various evolutionary stages since they are detected in all the fields.The detection rates of N-bearing molecules decrease as the clumps evolve,but those of O-bearing species increase with evolution.Furthermore,the abundance ratios[N2H^＋]/[HCO^＋]and log（[HC3N]/[HCO^＋]）decline with log（[HCO^＋]）as two linear functions,respectively.This suggests that N^＋2H^＋ and HC3N transform to HCOas the clumps evolve.We also find that C2H is the most abundant molecule with an order of magnitude 10^（-8）.In addition,three new infall candidates,G010.214–00.324,G011.121–00.128 and G012.215–00.118（a）,are discovered to have large-scale infall motions and infall rates with an order of magnitude 10^（-3）M⊙yr^（-1）.