Dynamical dark energy beyond Planck? Constraints from multiple CMB probes, DESI BAO, and type-Ia supernovae

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 <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mn>2.8</a:mn><a:mi>σ</a:mi></a:mrow></a:math> to <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mn>4.2</c:mn><c:mi>σ</c:mi></c:math>. 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 Wilkinson microwave anisotropy probe (WMAP) 9-yr observations at large angular scales. My analysis shows that ACT and WMAP data, when combined with DESI BAO and <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mrow><e:mi>Pantheon</e:mi><e:mo>+</e:mo></e:mrow></e:math> supernovae, yield independent constraints with a precision comparable to Planck. Notably, in this case, the cosmological constant value is recovered within 2 standard deviations. A preference for DDE reappears when <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"><g:mrow><g:mi>Pantheon</g:mi><g:mo>+</g:mo></g:mrow></g:math> 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 <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"><i:mrow><i:mi>Pantheon</i:mi><i:mo>+</i:mo></i:mrow></i:math> 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 <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"><k:mo>ℓ</k:mo><k:mo>≲</k:mo><k:mn>30</k:mn></k:math>.