A hybrid approach to CMB lensing reconstruction on all-sky intensity maps

Understand

Based on realistic simulations, we propose an hybrid method to reconstruct the lensing potential power spectrum, directly on PLANCK-like CMB frequency maps.

• It implies using a large galactic mask and dealing with a strong inhomogeneous noise.
• For l < 100, we show that a full-sky inpainting method, already described in a previous work, still allows a minimal variance reconstruction, with a bias that must be accounted for by a Monte-Carlo method, but that does not couple to the deflection field.
• For l>100 we develop a method based on tiling the cut-sky with local 10x10 degrees overlapping tangent planes (referred to in the following as &#34;patches&#34;).