Detectability of Galactic Faraday Rotation in multiwavelength CMB observations: A cross-correlation analysis of CMB and radio maps

Matthew Kolopanis, Philip Mauskopf, Judd Bowman

Research output: Contribution to journalArticle


We introduce a new cross-correlation method to detect and verify the astrophysical origin of Faraday Rotation (FR) inmultiwavelength surveys. FR is well studied in radio astronomy from radio point sources but the λ2 suppression of FR makes detecting and accounting for this effect difficult at millimeter and sub-millimeter wavelengths. Therefore, statistical methods are used to attempt to detect FR in the cosmic microwave background (CMB). Most estimators of the FR power spectrum rely on single-frequency data. In contrast, we investigate the correlation of polarized CMB maps with FR measure maps from radio point sources. We show a factor of ~30 increase in sensitivity over single-frequency estimators and predict detections exceeding 10σ significance for a CMB-S4-like experiment. Improvements in observations of FR from current and future radio polarization surveyswill greatly increase the usefulness of thismethod.

Original languageEnglish (US)
Pages (from-to)4795-4804
Number of pages10
JournalMonthly Notices of the Royal Astronomical Society
Issue number4
Publication statusPublished - Jan 1 2016



  • Cosmic background radiation
  • Cosmology: miscellaneous
  • Methods: data analysis

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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