paper

Implications for the Hubble tension from the ages of the oldest astrophysical objects

arXiv:2105.10421 · doi:10.1016/j.jheap.2022.07.004

Abstract

We use the ages of old astrophysical objects (OAO) in the redshift range as stringent tests of the late-time cosmic expansion history. Since the age of the Universe at any redshift is inversely proportional to , requiring that the Universe be older than the oldest objects it contains at any redshift, provides an upper limit on . Using a combination of galaxies imaged from the CANDELS program and various high- quasars, we construct an age-redshift diagram of OAO up to . Assuming the CDM model at late times, we find the 95\% confidence level upper limit , in slight disagreement with a host of local measurements. Taken at face value, and assuming that the OAO ages are reliable, this suggests that ultimately a combination of pre- and post-recombination () new physics might be required to reconcile cosmic ages with early-time and local measurements. In the context of the Hubble tension, our results motivate the study of either combined global pre- and post-recombination modifications to CDM, or local new physics which only affects the local measurements.

16 pages, 2 figures. v2: additional references added, version accepted for publication in JHEAp

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