Polarization fraction of Planck Galactic cold clumps and forecasts for the Simons Observatory

Understand

We measure the polarization fraction of a sample of $6282$ Galactic cold clumps at $353 \, \mathrm{GHz} $, consisting of $Planck$ Galactic cold clump (PGCC) catalogue category 1 objects (flux densities measured with signal-to-noise ratio $(\mathrm{S/N}) > 4$).

• We find the mean-squared polarization fraction at $353 \, \mathrm{GHz} $ to be $ \langle \Pi ^ 2 \rangle = [ 4.79 \pm 0.44 ] \times 10 ^ {-4} $ equating to an $ 11 \, \sigma $ detection of polarization.
• We test if the polarization fraction depends on the clumps' physical properties, including flux density, luminosity, Galactic latitude and physical distance.
• We see a trend towards increasing polarization fraction with increasing Galactic latitude, but find no evidence that polarization depends on the other tested properties.