Supermassive black hole evolution

[Chronos]

This paper; http://arxiv.org/abs/1601.05473, The Early Growth of the First Black Holes discusses the evolution of supermassive massive black holes [SMBH] as inferred from observations of high z quasars: which has provoked questions about the putatitve age of the universe and the time it allows for formation of such objects. The hierarchical theory of SMBH formation has come under increasing fire for reasons including the apparent need for super eddington accretion rates and dissipative effects expected from primordial stars in the early universe. As a consequence, the direct collapse black hole [DCBH] hypothesis has gained increasing traction in the cosmology community. The paper offers further evidence consistent with this idea.

 

[marcus]

It's a key unsolved problem and it's worth noting that this is an invited review article.