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arXiv · 2507.18547

An S-shaped filament formed due to Cloud-Cloud Collision in molecular cloud G178.28-00.61

Tianwei Zhang·Tie Liu·Yuefang Wu·Linjing Feng·Sihan Jiao·Derek Ward-Thompson·Alessio Traficante·Helen J Fraser·James Di Francesco·Doug Johnstone·Paul F. Goldsmith·Yasuo Doi·Xunchuan Liu·Chang Won Lee·Fengwei Xu·Ram K. Yadav·Glenn J White·Leonardo Bronfman·Yi-Jehng Kuan·Kee-Tae Kim·Donghui Quan
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Abstract

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.

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Tianwei Zhang, Tie Liu, Yuefang Wu, Linjing Feng, Sihan Jiao, Derek Ward-Thompson, Alessio Traficante, Helen J Fraser, James Di Francesco, Doug Johnstone, Paul F. Goldsmith, Yasuo Doi, Xunchuan Liu, Chang Won Lee, Fengwei Xu, Ram K. Yadav, Glenn J White, Leonardo Bronfman, Yi-Jehng Kuan, Kee-Tae Kim, Donghui Quan. 2025-07-24. An S-shaped filament formed due to Cloud-Cloud Collision in molecular cloud G178.28-00.61. https://doi.org/10.3847/1538-4365%2Fadf203

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