2011/06/27 by Samuel J. George, J. M. Stil, Jeroen M. Stil +2 · 2 citations
Environmental Science · Mathematics · Physics and Astronomy · #Computational physics #Faraday cage #Faraday effect #Gaussian #Intensity (physics) #Mathematics #Monte Carlo method #Optics #Physics #Polarization (electrochemistry) #Quantum mechanics #Scattering #Scientific Research and Discoveries #Soil Geostatistics and Mapping #Statistical and numerical algorithms #Statistics #Stokes parameters #astro-ph.CO #astro-ph.IM
paper · pdf · doi:10.1071/as11027
8 pages, 8 figures, accepted for publication in Publications of the Astronomical Society of Australia
arxiv created 2011/06/27 · openalex publication_date 2011/10/05 · arxiv updated 2015/05/28 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Abstract Detection thresholds in polarized intensity and polarization bias correction are investigated for surveys where the polarization information is obtained from rotation measure (RM) synthesis. Considering unresolved sources with a single RM, a detection threshold of 8 σ QU applied to the Faraday spectrum will retrieve the RM with a false detection rate less than 10 −4 , but polarized intensity is more strongly biased than Ricean statistics suggest. For a detection threshold of 5 σ QU , the false detection rate increases to ∼4%, depending also on λ 2 coverage and the extent of the Faraday spectrum. Non-Gaussian noise in Stokes Q and U due to imperfect imaging and calibration can be represented by a distribution that is the sum of a Gaussian and an exponential. The non-Gaussian wings of the noise distribution increase the false detection rate in polarized intensity by orders of magnitude. Monte Carlo simulations assuming non-Gaussian noise in Q and U give false detection rates at 8 σ QU similar to Ricean false detection rates at 4.9 σ QU .