The HP2 Survey - IV. The Pipe nebula: Effective dust temperatures in
  dense cores
  Multi-wavelength observations in the sub-mm regime provide information on the
distribution of both the dust column density and the effective dust temperature
in molecular clouds. In this study, we created high-resolution and
high-dynamic-range maps of the Pipe nebula region and explored the value of
dust-temperature measurements in particular towards the dense cores embedded in
the cloud. The maps are based on data from the Herschel and Planck satellites,
and calibrated with a near-infrared extinction map based on 2MASS observations.
We have considered a sample of previously defined cores and found that the
majority of core regions contain at least one local temperature minimum.
Moreover, we observed an anti-correlation between column density and
temperature. The slope of this anti-correlation is dependent on the region
boundaries and can be used as a metric to distinguish dense from diffuse areas
in the cloud if systematic effects are addressed appropriately. Employing
dust-temperature data thus allows us to draw conclusions on the
thermodynamically dominant processes in this sample of cores: external heating
by the interstellar radiation field and shielding by the surrounding medium. In
addition, we have taken a first step towards a physically motivated core
definition by recognising that the column-density-temperature anti-correlation
is sensitive to the core boundaries. Dust-temperature maps therefore clearly
contain valuable information about the physical state of the observed medium.
