Initial phases of high-mass star formation: A multiwavelength study
  towards the extended green object G12.42+0.50
  We present a multiwavelength study of the extended green object, G12.42+0.50
in this paper. The associated ionized, dust, and molecular components of this
source are studied in detail employing various observations at near-, mid- and
far-infrared, submillimeter and radio wavelengths. Radio continuum emission
mapped at 610 and 1390 MHz, using the Giant Meterwave Radio Telescope, India,
advocates for a scenario of coexistence of an UC H II region and an ionized
thermal jet possibly powered by the massive young stellar object, IRAS
18079-1756 with an estimated spectral type of B1 - B0.5. Shock-excited lines of
H2 and [FeII], as seen in the near-infrared spectra obtained with UKIRT-UIST,
lend support to this picture. Cold dust emission shows a massive clump of mass
1375 M{\sun} enveloping G12.42+0.50. Study of the molecular gas kinematics
using the MALT90 and JCMT archival data unravels the presence of both infall
activity and large-scale outflow suggesting an early stage of massive star
formation in G12.42+0.50. A network of filamentary features are also revealed
merging with the massive clump mimicking a hub-filament layout. Velocity
structure along these indicate bulk inflow motion.
