Dust in a compact, cold, high-velocity cloud: A new approach to removing
  foreground emission
  Because isolated high-velocity clouds (HVCs) are found at great distances
from the Galactic radiation field and because they have subsolar metallicities,
there have been no detections of dust in these structures. A key problem in
this search is the removal of foreground dust emission. Using the
Effelsberg-Bonn HI Survey and the Planck far-infrared data, we investigate a
bright, cold, and clumpy HVC. This cloud apparently undergoes an interaction
with the ambient medium and thus has great potential to form dust. To remove
the local foreground dust emission we used a regularised, generalised linear
model and we show the advantages of this approach with respect to other
methods. To estimate the dust emissivity of the HVC, we set up a simple
Bayesian model with mildly informative priors to perform the line fit instead
of an ordinary linear least-squares approach. We find that the foreground can
be modelled accurately and robustly with our approach and is limited mostly by
the cosmic infrared background. Despite this improvement, we did not detect any
significant dust emission from this promising HVC. The 3-sigma upper limit to
the dust emissivity is an order of magnitude below the typical values for the
Galactic interstellar medium.
