Scale-Dependent and Anisotropic Cosmic Birefringence: 8.5σ Isotropic and 4–5σ Directional
by Condit, Amy / 22 Blue CMB Birefringence & Standing-Wave Rotation Field·Updated 1mo ago
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Description
8.5σ isotropic and 4–5σ directional polarization rotation signals were measured in Planck 2018 SMICA and NILC component-separated polarization maps across the multipole range ℓ = 500–1500. The analysis, conducted by Amy Condit of the 22 Blue CMB Birefringence & Standing-Wave Rotation Field, uses linearized EB estimators and a quantitative q-mask to measure rotation angles as a function of angular scale. The dataset, last updated on 2026-06-17, includes figures illustrating isotropic and directional birefringence measurements and statistical validation.
Use Cases
Validate cosmological models predicting scale-dependent cosmic birefringence based on the measured rotation amplitude decreasing from 0.232° to 0.030° with increasing multipole.
Investigate anisotropic signatures in the CMB based on the detected North–South dipole with a rotation difference of approximately 2.3°.
Compare component separation methods using the consistent directional structure found in both SMICA and NILC maps.
Perform statistical validation of CMB anomalies using the provided Monte Carlo simulations and bootstrap variance calibration.
Strengths
High statistical significance for the isotropic signal (8.5σ) and directional components (4–5σ).
Analysis uses two independent component-separated maps (SMICA and NILC) showing consistent results.
Uncertainties are calibrated using 50 ΛCDM + noise realizations and bootstrap methods, yielding calibrated uncertainties of approximately σ(Δα) ≈ 0.4°.
Limitations
Column-level documentation is absent; field semantics must be inferred after download.
Row count is unknown, which may limit suitability assessment.
The dataset's coverage is limited to the Planck 2018 data and the specific multipole range ℓ = 500–1500.
Provenance
Source
Planck 2018 SMICA and NILC component-separated polarization maps.
Collection Method
Analysis using linearized EB estimators and a quantitative q-mask (fsky ≈ 0.467).
Freshness
Last updated 2026-06-17 19:45:28; freshness should be verified.
License information is unknown; users should verify terms of use for the underlying Planck data.