Tuning the cosmic instrument: robust cosmology through combined probes

Abstract

Abstract As wide-field surveys yield increasingly precise data, multiprobe analyses offer significant advantages. In this work, we use our previously developed framework for jointly analyzing cosmic microwave background (CMB) and large-scale structure data. We analyze combinations of three CMB ( Planck PR3, Planck PR4, and ACT+WMAP) datasets, DESI Y1 Baryon Acoustic Oscillation (BAO) data, and a 9 × 2pt low- z dataset comprising KiDS-1000, BOSS DR12, and Planck CMB lensing/Integrated Sachs Wolfe (including all cross-correlations). We first assess internal consistency, finding a mild (< 2 σ ) tension between CMB and low- z datasets in the full parameter space and hints of systematics in Planck PR3 and KiDS-1000. We then derive constraints in ΛCDM and, motivated by recent DESI results, dynamical dark energy ( w 0 w a CDM) and free neutrino mass extensions. In ΛCDM, we derive a novel 9 × 2pt constraint of S 8 = 0.777 +0.17 -0.17 and find strong consistency among CMB datasets. In w 0 w a CDM, adding low- z to CMB+BAO tightens ( w 0 , w a ) constraints by 50% (in figure-of-merit terms) in our baseline combination of Planck PR4 + low- z + BAO. The posterior accommodates a cosmological constant ( w 0 = -1, w a = 0) within 1 σ , in contrast to the ∼ 2 σ preference for evolving dark energy from CMB+BAO alone. For neutrino masses, our baseline dataset yields a systematics-robust constraint of M ν < 0.12eV in ν ΛCDM. Allowing dynamical dark energy and free neutrino mass ( νw 0 w a CDM) broadens and shifts the neutrino mass posterior higher, yielding a 1.8 σ constraint ( M ν = 0.16 +0.09 -0.09 eV) in our baseline. Our analysis demonstrates the power of multiprobe analyses for assessing tensions, identifying systematics and providing robust constraints.

Topics & Concepts