2018ApJ...869...30D

We present a multiwavelength observational study of IRAS 17008-4040 and IRAS 17009-4042 to probe the star formation (SF) mechanisms operational in both the sites. Each IRAS site is embedded within a massive ATLASGAL 870 µm clump (∼2430-2900 M_☉), and several parsec-scale filaments at 160 µm are radially directed toward these clumps (at T_d ∼ 25-32 K). The analysis of the Spitzer and VVV photometric data depicts a group of infrared-excess sources toward both the clumps, suggesting the ongoing SF activities. In each IRAS site, high-resolution GMRT radio maps at 0.61 and 1.28 GHz confirm the presence of H II regions, which are powered by B-type stars. In the site IRAS 17008-4040, a previously known O-star candidate without an H II region is identified as an infrared counterpart of the 6.7 GHz methanol maser emission (i.e., IRcmme). Based on the Very Large Telescope/NAOS-CONICA adaptive-optics L' image (resolution ∼0.''1), the source IRcmme is resolved into two objects (i.e., IRcmme1 and IRcmme2) within a scale of 900 au that are found to be associated with the Atacama Large Millimeter/submillimeter Array core G345.50M. IRcmme1 is characterized as the main accreting high mass protostellar object candidate before the onset of an ultracompact H II region. In the site IRAS 17009-4042, the 1.28 GHz map has resolved two radio sources that were previously reported as a single radio peak. Altogether, in each IRAS site, the junction of the filaments (i.e., massive clump) is investigated with the cluster of infrared-excess sources and the ongoing massive SF. This evidence is consistent with the "hub-filament" systems as proposed by Myers.