Trouble beyond H0 and the new cosmic triangles

The distance ladder using supernovae yields higher values of the Hubble constant H0 than those inferred from measurements of the cosmic microwave background (CMB) and galaxy surveys, a discrepancy that has come to be known as the "Hubble tension". This has motivated the exploration of exte...

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Bibliographic Details
Published in:Physical review. D 2021-05, Vol.103 (10), p.1
Main Authors: Bernal, José Luis, Verde, Licia, Jimenez, Raul, Kamionkowski, Marc, Valcin, David, Wandelt, Benjamin D
Format: Article
Language:English
Subjects:
Astronomical models
Big Bang theory
Constraint modelling
Cosmic microwave background
Cosmology
Decoupling
Density
Drag
Galaxies
Globular clusters
Horizon
Hubble constant
Radiation
Sound
Supernovae
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Summary:The distance ladder using supernovae yields higher values of the Hubble constant H0 than those inferred from measurements of the cosmic microwave background (CMB) and galaxy surveys, a discrepancy that has come to be known as the "Hubble tension". This has motivated the exploration of extensions to the standard cosmological model in which higher values of H0 can be obtained from CMB measurements and galaxy surveys. The trouble, however, goes beyond H0; such modifications affect other quantities, too. In particular, their effects on cosmic times are usually neglected. We explore here the implications that measurements of the age tU of the Universe, such as a recent inference from the age of the oldest globular clusters, can have for potential solutions to the H0 tension. The value of H0 inferred from the CMB and galaxy surveys is related to the sound horizon at CMB decoupling (or at radiation drag), but it is also related to the matter density and to tU. Given this observation, we show how model-independent measurements may support or disfavor proposed new-physics solutions to the Hubble tension. Finally, we argue that cosmological measurements today provide constraints that, within a given cosmological model, represent an overconstrained system, offering a powerful diagnostic tool of consistency. We propose the use of ternary plots to simultaneously visualize independent constraints on key quantities related to H0 like tU, the sound horizon at radiation drag, and the matter density parameter. We envision that this representation will help find a solution to the trouble of and beyond H0.
ISSN:2470-0010
2470-0029
DOI:10.1103/PhysRevD.103.103533