2013ApJ...764...72M

One cannot understand the early appearance of 10⁹ M_☉supermassive 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 ΛCDM, 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 M_☉ seeds produced after the onset of re-ionization (at z ≲ 15) could have easily grown to M ≳ 10⁹ M_☉ by z ≳ 6, merely by accreting at the standard Eddington rate.