Lifting weak lensing degeneracies with a field-based likelihood

Understand

We present a field-based approach to the analysis of cosmic shear data to infer jointly cosmological parameters and the dark matter distribution.

• This forward modelling approach samples the cosmological parameters and the initial matter fluctuations, using a physical gravity model to link the primordial fluctuations to the non-linear matter distribution.
• Cosmological parameters are sampled and updated consistently through the forward model, varying (1) the initial matter power spectrum, (2) the geometry through the distance-redshift relationship, and (3) the growth of structure and light-cone effects.
• Our approach extracts more information from the data than methods based on two-point statistics.