2025A&A...699A.137B

We study the G013.313+0.193 (G013.313) region, a complex environment characterised by molecular cloud interactions indicative of cloud-cloud collision (CCC). Observations of the NH₃ (1,1) and (2,2) inversion transitions were obtained using the Nanshan 26 m radio telescope, while HCO⁺ (J = 1-0), ¹²CO, ¹³CO, and C¹⁸O (J = 1-0) transitions from the 14 m Purple Mountain Observatory Delingha (PMODLH) 14 m telescope. Archival data are also included. We identified key observational signatures of CCC, including complementary spatial distributions, U-shaped structures, bridge features, and V-shaped velocity distributions. The position-velocity (P-V) diagrams reveal clear indications of gas interaction between two velocity components, suggesting an ongoing collision at an estimated angle of ∼ 45° to the line of sight. The estimated collision timescale is 0.35-1.03 Myr, aligned with the inferred ages of young stellar objects (YSOs) in the region, supporting the hypothesis of collision-induced star formation. Hub-filament systems (HFSs) are identified in the compressed gas region, where filaments converge towards a dense hub, suggesting the CCC as a potential driver of HFS and massive star formation. The high column density (∼2 × 10²³ cm^–2) suggests favourable conditions for the formation of massive stars. Although alternative kinematic drivers such as longitudinal collapse and shear motion are considered, CCC remains the most plausible explanation for the observed features. Our findings contribute to our understanding of the mechanisms of cloud dynamics and massive star formation in turbulent molecular environments.