2025/10/07 by Reeves, Alexander, Ferraro, Simone, Nicola, Andrina +1 · 1 citation
#Astrophysics of Galaxies (astro-ph.GA) #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc)
paper · doi:10.48550/arxiv.2510.06114
We perform a multiprobe analysis combining cosmic microwave background (CMB) data from Planck and the Atacama Cosmology Telescope (ACT), ACT CMB lensing, and large-scale structure (LSS) measurements from the Dark Energy Spectroscopic Instrument (DESI), including DESI Legacy Imaging Survey (LS) galaxies and baryon acoustic oscillations (BAOs). We present the first 5×2pt analysis of ACT DR6 lensing, DESI LS, and Planck ISW. Within ΛCDM, this yields S8 = σ8(Ωm/0.3)0.5 = 0.819 ± 0.016, in good agreement with primary CMB inferences and provides a sound-horizon-free Hubble constant constraint of H0 = 70.0 ± 4.4 km s-1 Mpc-1. Then, combining with CMB primary and BAO, we reconfirm a CMB-BAO discrepancy in the Ωm-(Dv)/(rd) plane, which is heightened when combining BAO with the 5×2pt data vector. We explore two dark-energy extensions that may reconcile this: an early-time modification, early dark energy (EDE), and late-time dynamical dark energy (DDE) parameterized by w0wa. For CMB primary+BAO+5×2pt, we find a 3.3σ preference for DDE over ΛCDM, while EDE is modestly favoured at 2.3σ. The models address different shortcomings of ΛCDM: DDE relaxes the neutrino mass bound (Mν<0.17eV vs. <0.050eV under ΛCDM), making it compatible with neutrino oscillation measurements, while EDE raises the Hubble constant to H0=70.5±1.2 \mathrmkm s-1 Mpc-1, easing the discrepancy with SH0ES. However, neither model resolves both issues simultaneously. Our analysis indicates that both DDE and EDE remain viable extensions of ΛCDM within current uncertainties and demonstrates the capacity of combined probes to place increasingly stringent constraints on cosmological parameters.
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