Data Challenge Maps for lensing reconstruction

October 12 2021, Clem Pryke

In Data challenge maps I I introduced some simulated maps to be used for reanalysis to help determine PICO performance. These have been used successfully by Mathieu and others.

In this post I re-render exactly the same maps at nside=2048 for use in lensing reconstruction. I carefully use the exact same input alms - including noise up to ell=1024. I have made only bands from 52GHz and up since the large beams at lower frequencies mean there will be minimal information for use in lensing reconstruction.

The plots below show the spectra taken from the old nside=512 maps at left, and the new nside=2048 maps at right. I think these look sensible - noise and llcdm extend out to 2*nside as before. The PySM foreground model contains high ell fill in out to 3*512 so foreground goes to zero above ell=1536. Also note that there is no lensing scale down in the new nside=2048 maps - A_L=1.

The next step is to form some sort of ILC of these maps to reduce foreground and noise.