SimBIG: Cosmological Constraints using Simulation-Based Inference of Galaxy Clustering with Marked Power Spectra

We present the first ΛCDM cosmological analysis performed on a galaxy survey using marked power spectra. The marked power spectrum is the two-point function of a marked field, where galaxies are weighted by a function that depends on their local density. The presence of the mark leads these statistics to contain higher-order information of the original galaxy field, making them a good candidate to exploit the non-Gaussian information of a galaxy catalog. In this work we make use of , a forward modeling framework for galaxy clustering analyses, and perform simulation-based inference using normalizing flows to infer the posterior distribution of the ΛCDM cosmological parameters. We consider different mark configurations (ways to weight the galaxy field) and deploy them in the  pipeline to analyze the corresponding marked power spectra measured from a subset of the BOSS galaxy sample. We analyze the redshift-space mark power spectra decomposed in ℓ = 0, 2, 4 multipoles and include scales up to the non-linear regime. Among the various mark configurations considered, the ones that give the most stringent cosmological constraints produce posterior median and 68% confidence limits on the growth of structure parameters equal to Ω_m=0.273^+0.040_-0.030 and σ_8=0.777^+0.077_-0.071. Compared to a perturbation theory analysis using the power spectrum of the same dataset, the  marked power spectra constraints on σ_8 are up to 1.2× tighter, while no improvement is seen for the other cosmological parameters.