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arXiv · 2206.06066

Unraveling the observational signatures of cloud-cloud collision and hub-filament systems in W31

A. K. Maity·L. K. Dewangan·H. Sano·K. Tachihara·Y. Fukui·N. K. Bhadari
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Abstract

To understand the formation process of massive stars, we present a multi-scale and multi-wavelength study of the W31 complex hosting two extended HII regions (i.e., G10.30-0.15 (hereafter, W31-N) and G10.15-0.34 (hereafter, W31-S)) powered by a cluster of O-type stars. Several Class I protostars and a total of 49 ATLASGAL 870 $μ$m dust clumps (at d = 3.55 kpc) are found toward the HII regions where some of the clumps are associated with the molecular outflow activity. These results confirm the existence of a single physical system hosting the early phases of star formation. The Herschel 250 $μ$m continuum map shows the presence of hub-filament system (HFS) toward both W31-N and W31-S. The central hubs harbour HII regions and they are depicted with extended structures (with T$_{\text{d}}$ $\sim$ 25-32 K) in the Herschel temperature map. In the direction of W31-S, an analysis of the NANTEN2 $^{12}$CO(J = 1-0) and SEDIGISM $^{13}$CO(J = 2-1) line data supports the presence of two cloud components around 8 and 16 km s$^{-1}$, and their connection in velocity space. A spatial complementary distribution between the two cloud components is also investigated toward W31-S, where the signposts of star formation, including massive O-type stars, are concentrated. These findings favor the applicability of cloud-cloud collision (CCC) around $\sim$2 Myr ago in W31-S. Overall, our observational findings support the theoretical scenario of CCC in W31, which explains the formation of massive stars and the existence of HFSs.

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A. K. Maity, L. K. Dewangan, H. Sano, K. Tachihara, Y. Fukui, N. K. Bhadari. 2022-06-13. Unraveling the observational signatures of cloud-cloud collision and hub-filament systems in W31. https://doi.org/10.3847/1538-4357%2Fac7872

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