Pillai, T. G. S.T. G. S.PillaiUrquhart, J. S.J. S.UrquhartLeurini, SilviaSilviaLeuriniZhang, Q.Q.ZhangTRAFICANTE, AlessioAlessioTRAFICANTEColombo, D.D.ColomboWang, K.K.WangGomez, L.L.GomezWyrowski, F.F.Wyrowski2025-01-102025-01-1020230035-8711http://hdl.handle.net/20.500.12386/35610The evolutionary sequence for high-mass star formation starts with massive starless clumps that go on to form protostellar, young stellar objects and then compact H II regions. While there are many examples of the three later stages, the very early stages have proved to be elusive. We follow-up a sample of 110 mid-infrared dark clumps selected from the ATLASGAL catalogue with the IRAM telescope in an effort to identify a robust sample of massive starless clumps. We have used the HCO<SUP>+</SUP> and HNC (1-0) transitions to identify clumps associated with infall motion and the SiO (2-1) transition to identity outflow candidates. We have found blue asymmetric line profile in 65 per cent of the sample, and have measured the infall velocities and mass infall rates (0.6-36 × 10<SUP>-3</SUP> M<SUB>⊙</SUB> yr<SUP>-1</SUP>) for 33 of these clumps. We find a trend for the mass infall rate decreasing with an increase of bolometric luminosity to clump mass, i.e. star formation within the clumps evolves. Using the SiO 2-1 line, we have identified good outflow candidates. Combining the infall and outflow tracers reveals that 67 per cent of quiescent clumps are already undergoing gravitational collapse or are associated with star formation; these clumps provide us with our best opportunity to determine the initial conditions and study the earliest stages of massive star formation. Finally, we provide an overview of a systematic high-resolution ALMA study of quiescent clumps selected that allows us to develop a detailed understanding of earliest stages and their subsequent evolution.STAMPAenArticle10.1093/mnras/stad10732-s2.0-85159776302https://academic.oup.com/mnras/article/522/3/3357/7118047http://arxiv.org/abs/2305.04256v12023MNRAS.522.3357PFIS/05 - ASTRONOMIA E ASTROFISICA