Understand
We present a study on using delensing to enhance cosmic birefringence measurements based on full-sky, map-based simulations.
- In our analysis, we neglect foreground contamination and instrumental systematics to isolate the intrinsic impact of delensing on both isotropic and anisotropic birefringence.
- For the isotropic case, assuming a constant rotation angle of $\beta = 0.35^\circ$, delensing reduces the lensing-induced variance in the EB power spectrum, yielding an improvement in sensitivity of approximately 10% at 6 $\mu$K-arcmin noise and 25-40% at lower noise levels.
- For the anisotropic case, using simulations at 1 $\mu$K-arcmin noise, we reconstruct the birefringence angle for a scale-invariant spectrum and mitigate lensing bias by delensing, achieving a 50% reduction in the leading $N_{(0)}$ bias and a 30% improvement in the constraints on the amplitude $A_{CB}$.