  We present a panchromatic study of 11 (sub-)millimetre selected DSFGs with
spectroscopically confirmed redshift ($1.5< z_{\rm spec}<3$) in the GOODS-S
field, with the aim of constraining their astrophysical properties (e.g., age,
stellar mass, dust and gas content) and characterizing their role in the
context of galaxy evolution. The multi-wavelength coverage of GOODS-S, from
X-rays to radio band, allow us to model galaxy SED by using CIGALE with a novel
approach, based on a physical motivated modelling of stellar light attenuation
by dust. Median stellar mass ($\simeq6.5\times10^{10}$ M$_\odot$) and SFR
($\simeq241$ M$_\odot$ yr$^{-1}$) are consistent with galaxy main-sequence at
$z\sim2$. The galaxies are experiencing an intense and dusty burst of star
formation (median L$_{\rm IR}\simeq2\times10^{12}$ L$_\odot$), with a median
age of $750$ Myr. The high median content of interstellar dust (M$_{\rm
dust}\simeq5\times10^8$ M$_\odot$) suggests a rapid enrichment of the ISM (on
timescales $\sim10^8$ yr). We derived galaxy total and molecular gas content
from CO spectroscopy and/or Rayleigh-Jeans dust continuum ($10^{10}\lesssim$
M$_{\rm gas}/$M$_\odot\lesssim10^{11}$), depleted over a typical timescale
$\tau_{\rm depl}\sim200$ Myr. X-ray and radio luminosities suggest that most of
the galaxies hosts an accreting radio silent/quiet SMBH. This evidence, along
with their compact multi-wavelength sizes (median r$_{\rm ALMA}\sim$ r$_{\rm
VLA}=1.8$ kpc, r$_{\rm HST}=2.3$ kpc) measured from high-resolution imaging
($\theta_{\rm res}\lesssim$ 1 arcsec), indicates these objects as the high-z
star-forming counterparts of massive quiescent galaxies, as predicted e.g., by
the in-situ scenario. Four objects show some signatures of a
forthcoming/ongoing AGN feedback, that is thought to trigger the morphological
transition from star-forming disks to ETGs.
