English

Dynamical Dark Energy Beyond Planck? Constraints from multiple CMB probes, DESI BAO and Type-Ia Supernovae

Cosmology and Nongalactic Astrophysics 2025-07-09 v2 High Energy Physics - Phenomenology

Abstract

The latest Baryon Acoustic Oscillation (BAO) measurements from the Dark Energy Spectroscopic Instrument (DESI) collaboration, when combined with Planck satellite Cosmic Microwave Background (CMB) data and Type Ia Supernovae, suggest a preference for Dynamical Dark Energy (DDE) at a significance level ranging from 2.8σ2.8\sigma to 4.2σ4.2\sigma. In this work, I test whether, and to what extent, this preference is supported by CMB experiments other than Planck. I analyze the latest Atacama Cosmology Telescope (ACT) and South Pole Telescope (SPT) temperature, polarization, and lensing spectra at small scales, eventually combining them with Planck or WMAP 9-year observations at large angular scales. My analysis shows that ACT and WMAP data, when combined with DESI BAO and Pantheon-plus Supernovae, yield independent constraints with a precision comparable to Planck. Notably, in this case, the cosmological constant value is recovered within two standard deviations. A preference for DDE reappears when Pantheon-plus is replaced with distance moduli measurements from the Dark Energy Survey Supernova program (DESy5). However, it remains less pronounced compared to the Planck-based results. When considering SPT data, no clear preference for DDE is found in combinations involving Pantheon-plus Supernovae, and the preference is significantly weaker in combinations involving DESy5. Overall, CMB experiments other than Planck generally weaken the evidence for DDE. I argue that the subsets of Planck data that strengthen the shift toward DDE are the temperature and E-mode polarization anisotropy measurements at large angular scales 30\ell \lesssim 30.

Keywords

Cite

@article{arxiv.2409.17074,
  title  = {Dynamical Dark Energy Beyond Planck? Constraints from multiple CMB probes, DESI BAO and Type-Ia Supernovae},
  author = {William Giarè},
  journal= {arXiv preprint arXiv:2409.17074},
  year   = {2025}
}

Comments

22 pages, 9 figures, 8 tables. V2: All results have been updated using the latest DESI-DR2 BAO measurements and ACT-DR6 CMB data. The main conclusions of the study are confirmed. Appendix B has been added to include additional tests clarifying the role of the optical depth at reionization and the matter density parameters in the results. Version accepted for publication in PRD