We study multiwavelength and multiscale data to investigate the kinematics of molecular gas associated with the star-forming complexes G045.49+00.04 (G45E) and G045.14+00.14 (G45W) in the Aquila constellation. An analysis of the FUGIN 13CO(1–0) line data unveils the presence of a giant molecular filament (GMF G45.3+0.1; length ∼75 pc, mass ∼1.1 × 106 M ⊙) having a coherent velocity structure at [53, 63] km s−1. The GMF G45.3+0.1 hosts G45E and G45W complexes at its opposite ends. We find large-scale velocity oscillations along GMF G45.3+0.1, which also reveals the linear velocity gradients of −0.064 and +0.032 km s−1 pc−1 at its edges. The photometric analysis of point-like sources shows the clustering of young stellar object (YSO) candidate sources at the filament’s edges where the presence of dense gas and H ii regions are also spatially observed. The Herschel continuum maps along with the CHIMPS 13CO(3–2) line data unravel the presence of parsec scale hub-filament systems (HFSs) in both sites, G45E and G45W. Our study suggests that the global collapse of GMF G45.3+0.1 is end dominated, with the addition to the signature of global nonisotropic collapse at the edges. Overall, GMF G45.3+0.1 is the first observational sample of filament where the edge-collapse and the hub-filament configurations are simultaneously investigated. These observations open the new possibility of massive star formation, including the formation of HFSs.

To understand the formation process of massive stars, we present a multiscale and multiwavelength study of the W31 complex hosting two extended H ii 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 μm dust clumps (at d = 3.55 kpc) are found toward the H ii 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 μm continuum map shows the presence of a hub-filament system (HFS) toward both W31-N and W31-S. The central hubs harbor H ii regions and they are depicted with extended structures (with T d ∼ 25–32 K) in the Herschel temperature map. In the direction of W31-S, an analysis of the NANTEN2 12CO(J = 1−0) and SEDIGISM 13CO(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 ∼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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