Inference of matter power spectrum at z=0 using DESI DR1 Full-Shape data

TL;DR

This paper reconstructs the present-day matter power spectrum at redshift zero using DESI DR1 galaxy clustering data and CMB observations, applying EFT modelling to test cosmological models.

Contribution

It extends previous analyses by incorporating higher-quality data and applying EFT to robustly test the consistency of ΛCDM and w0waCDM models with galaxy clustering and CMB data.

Findings

Both ΛCDM and w0waCDM models fit the data consistently.

EFT modelling improves robustness over traditional methods.

No significant discrepancies found between datasets.

Abstract

Measurements of galaxy distributions at large cosmic distances capture clustering from the past. In this study, we use a cosmological model to translate these observations into the present-day galaxy distribution. Specifically, we reconstruct the 3D matter power spectrum at redshift $ z = 0 $ using Dark Energy Spectroscopic Instrument (DESI) Year 1 (DR1) galaxy clustering data and Cosmic Microwave Background (CMB) observations, assuming the $ \Lambda \text{CDM} $ model, and compare it to the result assuming the $ w_0w_a \text{CDM} $ model. Building on previous state-of-the-art methods, we apply Effective Field Theory (EFT) modelling of the galaxy power spectrum to account for small-scale effects in the 2-point statistics of galaxy data. The EFT approach offers a more robust methodology than traditional methods for modelling the galaxy power spectrum from galaxy clustering data, which can be used to test the consistency of the assumed cosmological model. By incorporating both CMB and galaxy clustering data across a range of redshifts, we can identify discrepancies between the datasets, which would indicate potential inaccuracies in the assumed expansion history. While previous studies have shown consistency with $ \Lambda \text{CDM} $, this work extends the analysis with higher-quality data to further test the expansion histories of both $ \Lambda \text{CDM} $ and $ w_0w_a \text{CDM} $. Our findings show that both $ \Lambda \text{CDM} $ and $ w_0w_a \text{CDM} $ provide consistent fits to the matter power spectrum recovered from DESI DR1 data.