The physical environment around IRAS 17599-2148: infrared dark cloud and
  bipolar nebula
  We present a multi-scale and multi-wavelength study to investigate the star
formation process around IRAS 17599$-$2148 that is part of an elongated
filamentary structure (EFS) (extension $\sim$21 pc) seen in the {\it Herschel}
maps. Using the {\it Herschel} data analysis, at least six massive clumps
(M$_{clump}$ $\sim$777 -- 7024 M$_{\odot}$) are found in the EFS with a range
of temperature and column density of $\sim$16--39~K and
$\sim$0.6--11~$\times$~10$^{22}$ cm$^{-2}$ (A$_{V}$ $\sim$7--117 mag),
respectively. The EFS hosts cold gas regions (i.e. infrared dark cloud) without
any radio detection and a bipolar nebula (BN) linked with the H\,{\sc ii}
region IRAS 17599$-$2148, tracing two distinct environments inferred through
the temperature distribution and ionized emission. Based on virial analysis and
higher values of self-gravitating pressure, the clumps are found unstable
against gravitational collapse. We find 474 young stellar objects (YSOs) in the
selected region and $\sim$72\% of these YSOs are found in the clusters
distributed mainly toward the clumps in the EFS. These YSOs might have
spontaneously formed due to processes not related to the expanding H\,{\sc ii}
region. At the edges of BN, four additional clumps are also associated with
YSOs clusters, which appear to be influenced by the expanding H\,{\sc ii}
region. The most massive clump in the EFS contains two compact radio sources
traced in the GMRT 1.28 GHz map and a massive protostar candidate, IRS~1 prior
to an ultracompact H\,{\sc ii} phase. Using the VLT/NACO near-infrared images,
IRS~1 is resolved with a jet-like feature within a 4200~AU scale.
