A statistical study towards high-mass BGPS clumps
with the MALT90 survey
Xiao-Lan Liu;Jin-Long Xu;Chang-Chun Ning;Chuan-Peng Zhang;Xiao-Tao Liu
【期刊名称】《天文和天体物理学研究》 【年(卷),期】2018(018)001
【摘要】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),HN13C(1-0),H13CO+(1-0),C2H(1-0),HC3N(10-9),SiO(2-1),13CS(2-1)and HNCO(44,0-30,3))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 N2H+ and HC3N transform to HCO+ as 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,G0 10.214-00.324,G0 11.121-00.128 and G0 12.215-00.118(a),are discovered to have large-scale infall motions and infall rates with an order of magnitude 10-3 M⊙ yr-1.
A statistical study towards high-mass BGPS clumps with the MALT90 survey
