Molecular gas associated with IRAS 10361-5830
  We analyze the distribution of the molecular gas and the dust in the
molecular clump linked to IRAS 10361-5830, located in the environs of the
bubble-shaped HII region Gum 31 in the Carina region, with the aim of
determining the main parameters of the associated material and investigating
the evolutionary state of the young stellar objects identified there.
  Using the APEX telescope, we mapped the molecular emission in the J=3-2
transition of three CO isotopologues, 12CO, 13CO and C18O, over a 1.5' x 1.5'
region around the IRAS position. We also observed the high density tracers CS
and HCO+ toward the source. The cold dust distribution was analyzed using
submillimeter continuum data at 870 \mu\ obtained with the APEX telescope.
Complementary IR and radio data at different wavelengths were used to complete
the study of the ISM.
  The molecular gas distribution reveals a cavity and a shell-like structure of
~ 0.32 pc in radius centered at the position of the IRAS source, with some
young stellar objects (YSOs) projected onto the cavity. The total molecular
mass in the shell and the mean H$_2$ volume density are ~ 40 solar masses and
~(1-2) x 10$^3$ cm$^{-3}$, respectively. The cold dust counterpart of the
molecular shell has been detected in the far-IR at 870 \mu\ and in Herschel
data at 350 \mu. Weak extended emission at 24 \mu\ from warm dust is projected
onto the cavity, as well as weak radio continuum emission.
  A comparison of the distribution of cold and warm dust, and molecular and
ionized gas allows us to conclude that a compact HII region has developed in
the molecular clump, indicating that this is an area of recent massive star
formation. Probable exciting sources capable of creating the compact HII region
are investigated. The 2MASS source 10380461-5846233 (MSX G286.3773-00.2563)
seems to be responsible for the formation of the HII region.
