SimBIG: Cosmological Constraints using Simulation-Based Inference of Galaxy Clustering with Marked Power Spectra
arxiv(2024)
摘要
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.
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