A Hi-GAL study of the high-mass star-forming region G29.96-0.02
  Context. G29.96-0.02 is a high-mass star-forming cloud observed at 70, 160,
250, 350, and 500 microns as part of the Herschel survey of the Galactic Plane
during the Science Demonstration Phase. Aims. We wish to conduct a far-infrared
study of the sources associated with this star-forming region by estimating
their physical properties and evolutionary stage, and investigating the clump
mass function, the star formation efficiency and rate in the cloud. Methods. We
have identified the Hi-GAL sources associated with the cloud, searched for
possible counterparts at centimeter and infrared wavelengths, fitted their
spectral energy distribution and estimated their physical parameters. Results.
A total of 198 sources have been detected in all 5 Hi-GAL bands, 117 of which
are associated with 24 microns emission and 87 of which are not associated with
24 microns emission. We called the former sources 24 microns-bright and the
latter ones 24 microns-dark. The [70-160] color of the 24 microns-dark sources
is smaller than that of the 24 microns-bright ones. The 24 microns-dark sources
have lower L_bol and L_bol/M_env than the 24 microns-bright ones for similar
M_env, which suggests that they are in an earlier evolutionary phase. The
G29-SFR cloud is associated with 10 NVSS sources and with extended centimeter
continuum emission well correlated with the 70 microns emission. Most of the
NVSS sources appear to be early B or late O-type stars. The most massive and
luminous Hi-GAL sources in the cloud are located close to the G29-UC region,
which suggests that there is a privileged area for massive star formation
towards the center of the G29-SFR cloud. Almost all the Hi-GAL sources have
masses well above the Jeans mass but only 5% have masses above the virial mass,
which indicates that most of the sources are stable against gravitational
collapse. The sources with M_env > M_virial and that ...
