A new polarization amplitude bias reduction method

Matias Ambrosio Vidal Navarro, J. P. Leahy, C. Dickinson

    Research output: Contribution to journalArticlepeer-review

    128 Downloads (Pure)

    Abstract

    Polarization amplitude estimation is affected by a positive noise bias, particularly important in regions with low signal-to-noise ratio (SNR). We present a new approach to correct for this bias in the case there is additional information about the polarization angle. We develop the 'known-angle estimator' that works in the special case when there is an independent and high SNR (≳ 2σ) measurement of the polarization angle. It is derived for the general case where the uncertainties in the Q, U Stokes parameters are not symmetric. This estimator completely corrects for the polarization bias if the polarization angle is perfectly known. In the realistic case, where the angle template has uncertainties, a small residual bias remains, but that is shown to be much smaller that the one left by other classical estimators. We also test our method with more realistic data, using the noise properties of the three lower frequency maps of Wilkinson Microwave Anisotropy Probe. In this case, the known-angle estimator also produces better results than methods that do not include the angle information. This estimator is therefore useful in the case where the polarization angle is expected to be constant over different data sets with different SNR.

    Original languageEnglish
    Pages (from-to)698-709
    Number of pages12
    JournalMonthly Notices of the Royal Astronomical Society
    Volume461
    Issue number1
    Early online date7 Jun 2016
    DOIs
    Publication statusPublished - 1 Sept 2016

    Keywords

    • Methods: data analysis
    • Methods: statistical
    • Polarization
    • Radiation mechanisms: non-thermal
    • Techniques: polarimetric

    Fingerprint

    Dive into the research topics of 'A new polarization amplitude bias reduction method'. Together they form a unique fingerprint.

    Cite this