# Difference between revisions of "MapBasedR"

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We compute the B-mode power spectrum for each simulation and fit a primordial + lensing <math>C_\ell</math> template with amplitudes for both components (the first one being <math>r</math>). For this we only use multipoles <math>\ell>30</math>. | We compute the B-mode power spectrum for each simulation and fit a primordial + lensing <math>C_\ell</math> template with amplitudes for both components (the first one being <math>r</math>). For this we only use multipoles <math>\ell>30</math>. | ||

See result below for the no-delensing and 0.25-delensing cases. | See result below for the no-delensing and 0.25-delensing cases. | ||

− | [[File:clplot.png]] | + | |

+ | [[File:clplot.png|600px]] |

## Revision as of 17:30, 18 May 2016

## Summary

We checked the case in Victor's forecasts using our map-based code on PySM simulations. Bullet-point results (details below):

- Assuming no delensing:
- Assuming a 0.25 delensing factor:

## Simulations

We used PySM to generate full-sky simulations including:

- Power-law synchrotron (spatially-varying spectral index).
- Single-component thermal dust (spatially-varying temperature and spectral index).
- , partially de-lensed CMB.
- Noise levels compatible with Victor's case.

The simulations are cut using a map defined by selecting the cleanest 4000 sq-deg of the sky in polarization.

## Foreground removal

We run a map-based bayesian foreground-removal code on the simulations. The code samples the fully-resolved amplitudes of the three different components as well as spectral parameters ( and ). The latter are assumed constant on larger pixels, with HEALPix resolution (corresponding to ~4 deg). Fig. below shows the B-mode map at 145 MHz (left) and the mean CMB-only B-mode map output by the code (right).

## Estimating r

We compute the B-mode power spectrum for each simulation and fit a primordial + lensing template with amplitudes for both components (the first one being ). For this we only use multipoles . See result below for the no-delensing and 0.25-delensing cases.