Star-forming site RAFGL 5085: Is a perfect candidate of hub-filament system?

To investigate the star-formation process, we present a multi-wavelength study of a massive star-forming site RAFGL 5085, which has been associated with the molecular outflow, Hii region and near-infrared cluster. The continuum images at 12, 250, 350 and 500 μm show a central region (having M<inf>clump</inf>∼ 225 M<inf>⊙</inf>) surrounded by five parsec-scale filaments, revealing a hub-filament system (HFS). In the Herschel column density (N(H <inf>2</inf>)) map, filaments are identified with higher aspect ratios (length/diameter) and lower N(H <inf>2</inf>) values (∼ 0.1–2.4 × 10 ²¹ cm^{- 2}), while the central hub is found with a lower aspect ratio and higher N(H <inf>2</inf>) values (∼ 3.5–7.0 × 10 ²¹ cm^{- 2}). The central hub displays a temperature range of [19, 22.5] K in the Herschel temperature map, and is observed with signatures of star formation (including radio continuum emission). The JCMT ¹³CO(J = 3–2) line data confirm the presence of HFS and its hub is traced with supersonic and non-thermal motions having higher Mach number and lower thermal to non-thermal pressure ratio. In the ¹³CO position–velocity diagrams, velocity gradients along the filaments towards the HFS appear to be observed, suggesting the gas flow in the RAFGL 5085 HFS and the applicability of the clump-fed scenario.