How robust are the parameter constraints extending the ΛCDM model?
arxiv(2024)
摘要
We present model-marginalized limits on the six standard ΛCDM
cosmological parameters (Ω_ c h^2, Ω_ b h^2,
θ_ MC, τ_ reio, n_s and A_s), as well as on selected
derived quantities (H_0, Ω_ m, σ_8, S_8 and r_
drag), obtained by considering three independent Cosmic Microwave Background
(CMB) experiments: the Planck satellite, the Atacama Cosmology Telescope, and
South Pole Telescope. We also consider low redshift observations in the form of
Baryon Acoustic Oscillation (BAO) data from the SDSS-IV eBOSS survey and
Supernovae (SN) distance moduli measurements from the Pantheon-Plus catalog.
The marginalized errors are stable against the different fiducial cosmologies
explored in this study. The largest impact on the parameter accuracy is
produced by varying the effective number of relativistic degrees of freedom
(N_ eff) or the lensing amplitude (A_ lens). Nevertheless the
marginalized errors on some derived parameters such as H_0 or Ω_
m can be up to two orders of magnitude larger than in the canonical
ΛCDM scenario when considering only CMB data. In these cases, low
redshift measurements are crucial for restoring the stability of the
marginalized cosmological errors computed here. Overall, our results underscore
remarkable stability in the mean values and precision of the main cosmological
parameters, making irrelevant the choice of different possible cosmological
scenarios once both high and low redshift probes are fully accounted for. The
very same results should be understood as a tool to test exotic cosmological
scenarios, as the marginalized values should be used in numerical analyses due
to their robustness and slightly larger errors, providing a more realistic and
conservative approach.
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