High-z Quasars in the R_h=ct Universe

TL;DR

This paper argues that high-redshift quasars with supermassive black holes are more plausibly explained by the R_h=ct universe model, which allows rapid growth of smaller seeds at lower redshifts, unlike the standard cosmological model.

Contribution

It demonstrates that the R_h=ct universe provides a more natural explanation for early supermassive black holes than the standard LCDM model.

Findings

High-z quasars can be explained by smaller seeds in R_h=ct universe.

Seeds formed after re-ionization can grow to supermassive sizes by z>6.

Standard model requires exotic assumptions to explain these quasars.

Abstract

One cannot understand the early appearance of 10^9 solar-mass black holes without invoking anomalously high accretion rates or the creation of exotically massive seeds, neither of which is seen in the local Universe. Recent observations have compounded this problem by demonstrating that most, if not all, of the high-z quasars appear to be accreting at the Eddington limit. In the context of LCDM, the only viable alternative now appears to be the assemblage of supermassive black holes via mergers, as long as the seeds started forming at redshifts >40, but ceased being created by z~20-30. In this paper, we show that, whereas the high-z quasars may be difficult to explain within the framework of the standard model, they can instead be interpreted much more sensibly in the context of the R_h=ct Universe. In this cosmology, 5-20 solar-mass seeds produced after the onset of re-ionization (at z<15) could have easily grown to M>10^9 solar masses by z> 6, merely by accreting at the standard Eddington rate.