Easing cosmic tensions with an open and hotter universe

Abstract

Despite the great observational success of the standard cosmological model some discrepancies in the inferred parameter constraints have manifested among a number of cosmological data sets. These include a tension between the expansion rate of our Cosmos as inferred from the cosmic microwave background (CMB) and as found from local measurements, the preference for an enhanced amplitude of CMB lensing, a somewhat low quadrupole moment of the CMB fluctuations as well as a preference for a lower amplitude of matter fluctuations in large-scale structure surveys than inferred from the CMB. We analyse these observational tensions under the addition of spatial curvature and a free CMB background temperature that may deviate from its locally measured value. With inclusion of these parameters, we observe a trend in the parameter constraints from CMB and baryon acoustic oscillation data towards an open and hotter universe with larger current expansion rate, standard CMB lensing amplitudes, lower amplitude of matter fluctuations, and marginally lower CMB quadrupole moment, consistently reducing the individual tensions among the cosmological data sets. Combining this data with local distance measurements, we find a preference for an open and hotter universe beyond the 99.7% confidence level. Finally, we briefly discuss a local void as a possible source for a deviation of the locally measured CMB temperature from its background value and as mimic of negative spatial curvature for CMB photons. This interpretation implies a $\sim$20% underdensity in our local neighbourhood of $\sim$10-100 Mpc in diameter, which is well within cosmic variance.

5 pages, 2 figures. Updated discussion on local void interpretation

References in corpus (7)

• Large Magellanic Cloud Cepheid Standards Provide a 1% Foundation for the Determination of the Hubble Constant and Stronger Evidence for Physics Beyond LambdaCDM
• KiDS-1000 Cosmology: Cosmic shear constraints and comparison between two point statistics
• Planck evidence for a closed Universe and a possible crisis for cosmology
• The Local Perspective on the Hubble Tension: Local Structure Does Not Impact Measurement of the Hubble Constant
• Sample variance in the local measurements of the Hubble constant
• H0 tension or T0 tension?
• Is there evidence for a hotter Universe?

Cited by in corpus (14)

• In the Realm of the Hubble tension $-$ a Review of Solutions
• Challenges for $\Lambda$CDM: An update
• Cosmology Intertwined II: The Hubble Constant Tension
• Cosmology Intertwined: A Review of the Particle Physics, Astrophysics, and Cosmology Associated with the Cosmological Tensions and Anomalies
• A void in the Hubble tension? The end of the line for the Hubble bubble
• Dark Energy as a Critical Phenomenon: a Resolution for Hubble Tension
• Planck ISW-lensing likelihood and the CMB temperature
• A critical discussion on the $H_0$ tension
• Cosmology in Minkowski space
• Possible Resolution of the Hubble Tension with Weyl Invariant Gravity
• The Hubble tension in the non-flat Super-$\Lambda \mathrm{CDM}$ model
• The effect of screening mechanisms on black hole binary inspiral waveforms
• The role of $T_0$ in CMB anisotropy measurements
• Cosmology with the SZ spectrum: measuring the Universe's temperature with galaxy clusters