The cosmic timeline implied by the highest redshift quasars

Abstract

The conventional picture of supermassive black-hole growth in the standard model had already been seriously challenged by the emergence of $\sim 10^9{M}_{\odot }$ quasars at $z\sim 7.5$, conflicting with the predicted formation of structure in the early $\hat{I}›$CDM Universe. But the most recent {\it JWST} discovery of a $\sim 10^8{M}_{\odot }$ source at $z\sim 10.1$ argues even more strongly against the possibility that these black holes were created in Pop II or III supernovae, followed by Eddington-limited accretion. Attempts at resolving this anomaly have largely focused on the formation of seeds via an exotic, direct collapse of primordial gas to an initial mass $\sim 10^5{M}_{\odot }$ -- a process that has never been seen anywhere in the cosmos. Our goal in this {\it Letter} is to demonstrate that the emergence of these black holes is instead fully consistent with standard astrophysics in the context of the alternative Friedmann-Lemaître-Robertson-Walker cosmology known as the $R_{\mathrm{h}}=ct$ universe. We show that, while the predicted evolution in the standard model is overly compressed, the creation, growth and appearance of such high-$z$ quasars fall comfortably within the evolutionary history in this cosmology, thereby adding considerable observational support to the existing body of evidence favoring it over the standard scenario.

6 pages, 2 figures. Accepted for publication in EPJ-C Letters