J1342+0928 Supports the Timeline in the R_h=ct Cosmology
  The discovery of quasar J1342+0928 (z=7.54) reinforces the time compression
problem associated with the premature formation of structure in LCDM. Adopting
the Planck parameters, we see this quasar barely 690 Myr after the big bang, no
more than several hundred Myr after the transition from Pop III to Pop II star
formation. Yet conventional astrophysics would tell us that a 10 solar-mass
seed, created by a Pop II/III supernova, should have taken at least 820 Myr to
grow via Eddington-limited accretion. This failure by LCDM constitutes one of
its most serious challenges, requiring exotic `fixes', such as anomalously high
accretion rates, or the creation of enormously massive (~10^5 solar-mass)
seeds, neither of which is ever seen in the local Universe, or anywhere else
for that matter. Indeed, to emphasize this point, J1342+0928 is seen to be
accreting at about the Eddington rate, negating any attempt at explaining its
unusually high mass due to such exotic means. In this paper, we aim to
demonstrate that the discovery of this quasar instead strongly confirms the
cosmological timeline predicted by the R_h=ct universe. We assume conventional
Eddington-limited accretion and the time versus redshift relation in this model
to calculate when a seed needed to start growing as a function of its mass in
order to reach the observed mass of J1342+0928 at z=7.54. Contrary to the
tension created in the standard model by the appearance of this massive quasar
so early in its history, we find that in the R_h=ct cosmology, a 10 solar-mass
seed at z~15 (the start of the Epoch of Reionization at t~878 Myr) would have
easily grown into an 8 x 10^8 solar-mass black hole at z=7.54 (t~1.65 Gyr) via
conventional Eddington-limited accretion.
