ALMA-IMF

We characterize kinematic processes in the G012.80 protocluster. We primarily focused on the N 2 H + (1−0) emission to trace the dense and cold gas. Additionally, we used complementary lines such as DCN(3-2), H41 α , C 18 O(2−1), and SiO(5−4), as well as continuum maps. We performed a N 2 H + hyperfine spectral line fitting to analyze multiple velocity components and extract spectral parameters. We estimated velocity gradients, column densities, and line-mass profiles for the two main filaments in G012, which we named R1 and R2. The line-mass profiles follow λ ( ω ) = 5660M ⊙ pc −1 ( ω /pc) 0.30 for R1 and λ ( ω ) = 6943 M ⊙ pc −1 ( ω /pc) 0.20 for R2. This is much larger than profiles of typical low-mass filaments. R1 and R2 show disparate position-velocity (PV) features. R1 exhibits a transverse velocity gradient of 10.4 km s −1 pc −1 and a few dense cores. This velocity gradient is interpreted with a simple rotation toy model when combined with the line-mass profile, and it corresponds to a rotational timescale of ~0.1 Myr. In contrast, R2 exhibits compact velocity structures (ΔV < 2 km s −1 ), likely due to collapse, as evidenced by the comparatively large number of massive cores and protostellar outflows. R2 is forming prestellar and protostellar cores at a rate of ~ 55.3 M ⊙ Myr −1 , with an efficiency similar to the Orion integral shaped filament (ISF). The R1 filament, in contrast, lacks protostellar cores and only contains a few prestellar cores, resulting in an estimated star formation rate of ~4.2M ⊙ Myr −1 , which is lower by more than an order of magnitude than that of R2. Combining gas kinematics, core incidence, and the line-mass profiles, we suggest that R1 is younger and still rotates, while R2 has evolved to collapse with a higher star formation rate. G012 thus hosts filaments at different evolutionary stages.