Star forming regions linked to RCW78 and the discovery of a new IR
  bubble
  With the aim of investigating the presence of molecular and dust clumps
linked to two star forming regions identified in the expanding molecular
envelope of the stellar wind bubble RCW78, we analyzed the distribution of the
molecular gas and cold dust. To accomplish this study we performed dust
continuum observations at 870 \mu m and 13CO(2-1) line observations with the
APEX telescope, using LABOCA and SHeFI-1 instruments, respectively, and
analyzed Herschel images at 70, 160, 250, 350, and 500 \mu m. These
observations allowed us to identify cold dust clumps linked to region B (named
the Southern clump) and region C (clumps 1 and 2) and an elongated Filament.
Molecular gas was clearly detected linked to the Southern clump and the
Filament. The velocity of the molecular gas is compatible with the location of
the dense gas in the expanding envelope of RCW78. We estimate dust temperatures
and total masses for the dust condensations from the emissions at different
wavelengths in the far-IR and from the molecular line using LTE and the virial
theorem. Masses obtained through different methods agree within a factor of
2-6. CC-diagrams and SED analysis of young stellar objects confirmed the
presence of intermediate and low mass YSOs in the dust regions, indicating that
moderate star formation is present. In particular, a cluster of IR sources was
identified inside the Southern clump. The IRAC image at 8 \mu m revealed the
existence of an infrared dust bubble of 16 arcsec in radius probably linked to
the O-type star HD117797 located at 4 kpc. The distribution of the near and mid
infrared emission indicate that warm dust is associated with the bubble.
