ShapeFit: extracting the power spectrum shape information in galaxy surveys beyond BAO and RSD

In the standard (classic) approach, galaxy clustering measurements from spectroscopic surveys are compressed into baryon acoustic oscillations and redshift space distortions measurements, which in turn can be compared to cosmological models. Recent works have shown that avoiding this intermediate step fitting directly full power spectrum signal (full modelling) leads much tighter constraints on parameters. Here we show where extra information is coming extend classic approach with one additional effective parameter, such it captures, effectively, same amount of as modelling but a model-independent way. We validate new method (ShapeFit) mock catalogs, compare its performance finding both deliver equivalent results. The ShapeFit extension promotes analyses at level ones terms content, advantages i) being more model independent; ii) offering an understanding origin information; iii) allowing robust control impact observational systematics.