| Abstract : | Massive stars, though rare, play an important role in determining the gas dynamics, and impact the star foramtion efficiencies in a region. It has been observed that massive stars form in clusters, requiring a large amount of material with appropriate densities to form. The conditions in the massive, central hubs of hub-filament systems are favourable for the formation of such massive star bearing clusters. We look at RCW 117, an HII region located 2.3 kpc away towards Scorpius, almost 10 away from the Galactic midplane. The Herschel maps indicate a hub filamentary structure, with multiple filaments connected to a central hub. The column density maps generated using the Herschel images suggest multiple condensations along the filaments. We find that the maximum column density and dust temperature towards the hub is ~10^{23} cm^{-2} and ~41 K, respectively. We try to identify trends in parameters relating to filaments, such as widths, lengths, linear density, etc and also their fragmentation. The ionised gas distribution is mapped using low frequency radio observations using the Giant Meterwave Radio Telescope (GMRT) at 610 and 1280 MHz and analysed to obtain the spectral index and the characteristics of the ionising source. The Lyman continuum photon rate is ~9.8 x 10^{48} s^{-1}, which corresponds to single zero age main sequence star of type O6. The kinematics of the region are studied using molecular line data, which help in understanding the gas motions in the region, which is one of the important parameters determining the filamentary structure. Calculation of velocity dispersion towards the filaments reveals the dominance of non-thermal gas motions, and has a mean value ~2 km/s. Finally, we attempt to identify and classify young stellar objects in the region from near and mid-infrared catalogues, using colour-colour and colour-magnitude diagrams. |
