Context : Massive stars and their associated ionized ( H ii ) 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 ii regions are still poorly known .

Aims : To investigate the impact of H ii regions on the formation of filaments , we imaged the Galactic H ii 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 .

Methods : We used the large-format bolometer camera ArTéMiS on the APEX telescope and combined the high-resolution ArTéMiS data at 350 \mu m and 450 \mu m with Herschel -SPIRE/HOBYS data at 350 and 500 \mu m to ensure good sensitivity to a broad range of spatial scales .
This allowed us to study the dense gas distribution around RCW 120 with a resolution of 8 \arcsec or 0.05 pc at a distance of 1.34 kpc .

Results : 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 H ii 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 full width at half maximum ( FWHM ) of 0.09 pc , as observed for filaments in low-mass star-forming regions .

Conclusions : Using ArTéMiS data combined with Herschel -SPIRE data , we found evidence for compression from the inner part of the RCW 120 ionized region on the surrounding dense shell .
This compression is accompanied with a significant ( factor 5 ) increase of the local column density .
This study suggests that compression exerted by H ii regions may play a key role in the formation of filaments and may further act on their hosted star formation .
ArTéMiS data also suggest that RCW 120 might be a 3D ring , rather than a spherical structure .