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

Clancy, J., Puglisi, G., Clark, S. E., Coppi, G., Fabbian, G. ORCID:, Hervías-Caimapo, C., Hill, J. C., Nati, F. and Reichardt, C. L. 2023. Polarization fraction of Planck Galactic cold clumps and forecasts for the Simons Observatory. Monthly Notices of the Royal Astronomical Society 524 (3) , 3712–3723. 10.1093/mnras/stad2099

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We measure the mean-squared polarization fraction of a sample of 6282 Galactic cold clumps at 353 GHz, consisting of Planck Galactic cold clump (PGCC) catalogue category 1 objects [flux densities measured with signal-to-noise ratio (S/N) > 4]. At 353 GHz, we find the mean-squared polarization fraction, which we define as the mean-squared polarization divided by the mean-squared intensity, to be (4.79 ± 0.44) × 10−4 equation to an 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. The Simons Observatory, with angular resolution of order 1 arcmin and noise levels between 22 and K−arcmin at high frequencies, will substantially enhance our ability to determine the magnetic field structure in Galactic cold clumps. At significance, we predict the Simons Observatory will detect at least ∼12 000 cold clumps in intensity and ∼430 cold clumps in polarization. This number of polarization detections would represent a two orders of magnitude increase over the current Planck results. We also release software that can be used to mask these Galactic cold clumps in other analyses.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Physics and Astronomy
Publisher: Oxford University Press
ISSN: 0035-8711
Date of First Compliant Deposit: 30 January 2024
Date of Acceptance: 6 July 2023
Last Modified: 31 Jan 2024 15:15

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