Iterative curved sky s06b nofg lensing templates

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Julien Carron, April 10 2020

This pages describes the 100 iterative (maximum a posteriori, 'MAP') lensing map built from the s06b simulations without foreground, and the associated lensing templates.

The CMB likelihood model used to build the maps include:

  • Curved-sky geometry
  • An inhomogeneous noise model built from the hit map /project/projectdirs/cmbs4/expt_xx/06b/rhits/n2048.fits together with the empirically estimated central noise value
  • Exact deprojection of all B-modes from 2 to 200, to ensure these modes are not used to build the lensing template
  • Used are E-modes from 2 to 3000 and B-modes from 200 to 3000
  • The same mean-field is used for each iteration

The approximation to the mean-field leaves a residual sometimes visible near the edges of the patch. This is however restricted to low lensing multipoles, and does not affect the B-template quality.

A typical cross-correlation to the input lensing looks like this (calculated in the central region of the patch), where the L-modes relevant to the B-power are centred on L~500. The correlation there goes from ~85% to ~96%

        Cs MAP rho.pdf

The B-templates are built remapping the estimated unlensed E-mode

Across the central region, I estimate the residual B-power after template substraction to be about 0.1 (for something close to 0.3 for the QE, the starting point)

        Cs resAL.png