Context :

Aims : We present a multi-wavelength analysis of the infrared dust bubble S 24 , and the extended IR sources G341.220-0.213 and G341.217-0.237 located in its environs , with the aim of investigating the characteristics of the molecular gas and the interstellar dust linked to them , and analyzing the evolutionary state of the young stellar objects identified there and its relation to S 24 and the IR sources .

Methods : Using the APEX telescope , we mapped the molecular emission in the CO ( 2-1 ) , ^ { 13 } CO ( 2-1 ) , C ^ { 18 } O ( 2-1 ) , and ^ { 13 } CO ( 3-2 ) lines in a region of about 5 \arcmin \times 5 \arcmin in size around the bubble .
The cold dust distribution was analyzed using submillimeter continuum images from ATLASGAL and Herschel .
Complementary IR and radio data at different wavelengths were used to complete the study of the interstellar medium in the region .

Results : The molecular gas distribution shows that gas linked to the S 24 bubble , G341.220-0.213 , and G341.217-0.237 has velocities between –48.0 km s ^ { -1 } and –40.0 km s ^ { -1 } , compatible with a kinematical distance of 3.7 kpc generally adopted for the region .
The gas distribution reveals a shell-like molecular structure of \sim 0.8 pc in radius bordering the S 24 bubble .
A cold dust counterpart of the shell is detected in the LABOCA and Herschel-SPIRE images .
The presence of weak extended emission at 24 \mu m from warm dust and radio continuum emission projected inside the bubble indicates the existence of exciting sources and that the bubble is a compact H ii region .
Part of the molecular gas bordering the S 24 H ii region coincides with the extended infrared dust cloud SDC341.194-0.221 .
A molecular and cold dust clump is present at the interface between the S 24 H ii region and G341.217-0.237 , shaping the eastern border of the IR bubble .
As regards G341.220-0.213 , the presence of an arc-like molecular structure encircling the northern and eastern sections of this IR source indicates that G341.220-0.213 is interacting with the molecular gas .
The analysis of the available IR point source catalogs reveals the existence of young stellar object ( YSO ) candidates linked to the IR extended sources , thus confirming their nature as active star-forming regions .
Gas and dust masses were estimated for the different features .
The total gas mass in the region and the H _ { 2 } ambient density amount to 10300 M _ { \odot } and 5900 cm ^ { -3 } , indicating that G341.220-0.213 , G341.217-0.237 , and the S 24 H ii region are evolving in a high density medium .
A triggering star formation scenario for the H ii region is investigated .

Conclusions :