We present compelling observational evidence supporting G178.28-00.61 as an early-stage candidate for Cloud-Cloud Collision (CCC), with indications of the formation of an S-shaped filament, evenly-separated dense cores, and young star clusters. The observations of CO molecular line emission demonstrate the existence of two interacting molecular clouds with systemic velocities of 0.8 km/s and -1.2 km/s, respectively. The convergence zone of these two clouds reveals an S-shaped filament in the JCMT 850 micron continuum image, suggesting cloud interaction. In line with expectations from CCC simulations, broad bridging features are discernible in the position-velocity diagrams. An elevated concentration of identified Class I and II young stellar objects along the filament at the intersection area further supports the hypothesis of a collision-induced origin. This observation could be explained by a recent MHD model of CCC (Kong et al. 2024), which predicts a similar morphology, scale, density, and unbound status, as well as the orientation of the polarization.
@article{arxiv.2507.18547,
title = {An S-shaped filament formed due to Cloud-Cloud Collision in molecular cloud G178.28-00.61},
author = {Tianwei Zhang and Tie Liu and Yuefang Wu and Linjing Feng and Sihan Jiao and Derek Ward-Thompson and Alessio Traficante and Helen J Fraser and James Di Francesco and Doug Johnstone and Paul F. Goldsmith and Yasuo Doi and Xunchuan Liu and Chang Won Lee and Fengwei Xu and Ram K. Yadav and Glenn J White and Leonardo Bronfman and Yi-Jehng Kuan and Kee-Tae Kim and Donghui Quan},
journal= {arXiv preprint arXiv:2507.18547},
year = {2025}
}