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

Abstract

In this work, we perform a statistical investigation towards 50 high-mass clumps using the data from the Bolocam Galactic Plane Survey (BGPS) and the Millimetre Astronomy Legacy Team 90-GHz survey (MALT90). Eleven dense molecular lines (N${}_2$H${}^{+}$(1-0), HNC(1-0), HCO${}^{+}$(1-0), HCN(1-0), HN${}^{13}$C(1-0), H${}^{13}$CO${}^{+}$(1-0), C${}_2$H(1-0), HC${}_3$N(10-9), SiO(2-1), ${}^{13}$CS(2-1) and HNCO$(4_{4,0}-3_{0,3}))$ are detected. N${}_2$H${}^{+}$ and HNC are shown to be good tracers for clumps in virous evolutionary stages since they are detected in all the fields. And 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 [N${}_2$H${}^{+}$]/[HCO${}^{+}$] and Log([HC${}_3$N]/[HCO${}^{+}$]) decline with Log([HCO${}^{+}$]) as two linear functions, respectively. This suggests the transformation of N${}_2$H${}^{+}$ and HC${}_3$N to HCO${}^{+}$ as the clumps evolve. We also find that C${}_2$H is the most abundant molecule with an order of $10^{-8}$. Besides, three new infall candidates G010.214-00.324, G011.121-00.128, and G012.215-00.118(a) are discovered to have large-scaled infall motions and infall rates in the magnitude of $10^{-3}$ M${}_{\odot }$ yr${}^{-1}$.

40 pages, 14 figures, 6 tables

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Cited by in corpus (5)

• The Hi-GAL compact source catalogue -- II. The 360° catalogue of clump physical properties
• Origin of the PN molecule in star-forming regions: the enlarged sample
• Establishing the evolutionary timescales of the massive star formation process through chemistry
• X-ray light curve in GRB 170714A: evidence for quark star?
• HNCO: A Molecule Traces Low-velocity Shock