Cloud-Cloud Collisions Induce Filament-Mediated Super Star Cluster Formation in the Antennae Overlap Region: Evidence from ALMA and JWST

Tomonari Michiyama; Toshiki Saito; Kouichiro Nakanishi; Daisuke Iono; Kazuki Tokuda; Kisetsu Tsuge; Yuzuki Nagashima; Shinya Komugi

arXiv · 2602.01616

Cloud-Cloud Collisions Induce Filament-Mediated Super Star Cluster Formation in the Antennae Overlap Region: Evidence from ALMA and JWST

Tomonari Michiyama·Toshiki Saito·Kouichiro Nakanishi·Daisuke Iono·Kazuki Tokuda·Kisetsu Tsuge·Yuzuki Nagashima·Shinya Komugi

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Abstract

The formation of super star clusters (SSCs) in galaxies remains a fundamental yet unresolved problem. Among the proposed mechanisms, cloud-cloud collisions (CCCs) have been suggested as a potential trigger, although observational validation has been limited. Here we present high-resolution ($0.12^{\prime\prime}$, $\sim14\,\mathrm{pc}$) ALMA observations of CO ($J=1\!-\!0$) emission toward a super giant molecular cloud (SGMC) in the overlap region of the Antennae galaxies. The data resolve the SGMC into two distinct velocity components separated by $\sim50\,\mathrm{km\,s^{-1}}$. One component exhibits a ``U-shaped'' structure within a large filament likely shaped by ram pressure, while the other shows hub-filament morphology. Such a morphology is naturally interpreted as a CCC scenario. The 108\,GHz continuum emission detected at the apparent collision interface is dominated by free-free radiation, with an ionizing photon rate consistent with the stellar mass and age of the optically identified SSCs. Supplementary infrared imaging with JWST reveals emission spatially coincident with the inferred collision interface, further supporting the CCC scenario. These results provide compelling, multi-wavelength evidence that CCCs play a key role in triggering SSC formation in merging galaxies.

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Tomonari Michiyama, Toshiki Saito, Kouichiro Nakanishi, Daisuke Iono, Kazuki Tokuda, Kisetsu Tsuge, Yuzuki Nagashima, Shinya Komugi. 2026-02-02. Cloud-Cloud Collisions Induce Filament-Mediated Super Star Cluster Formation in the Antennae Overlap Region: Evidence from ALMA and JWST. https://arxiv.org/abs/2602.01616

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