The role of Galactic HII regions in the formation of filaments.
  High-resolution submilimeter imaging of RCW 120 with ArT\'eMiS
  Massive stars and their associated ionized (HII) regions could play a key
role in the formation and evolution of filaments that host star formation.
However, the properties of filaments that interact with H regions are still
poorly known. To investigate the impact of HII regions on the formation of
filaments, we imaged the Galactic HII region RCW 120 and its surroundings where
active star formation takes place and where the role of ionization feedback on
the star formation process has already been studied. We used the ArT\'eMiS
camera on the APEX telescope and combined the ArT\'eMiS data at 350 and 450
microns with Herschel-SPIRE/HOBYS. We studied the dense gas distribution around
RCW 120 with a resolution of 8 arcsec (0.05 pc at a distance of 1.34 kpc). Our
study allows us to trace the median radial intensity profile of the dense shell
of RCW 120. This profile is asymmetric, indicating a clear compression from the
HII region on the inner part of the shell. The profile is observed to be
similarly asymmetric on both lateral sides of the shell, indicating a
homogeneous compression over the surface. On the contrary, the profile analysis
of a radial filament associated with the shell, but located outside of it,
reveals a symmetric profile, suggesting that the compression from the ionized
region is limited to the dense shell. The mean intensity profile of the
internal part of the shell is well fitted by a Plummer like profile with a
deconvolved Gaussian FWHM of 0.09 pc, as observed for filaments in low-mass
star-forming regions. This study suggests that compression exerted by HII
regions may play a key role in the formation of filaments and may further act
on their hosted star formation. ArT\'eMiS data also suggest that RCW 120 might
be a 3D ring, rather than a spherical structure
