83 quasars right up against the Event Horizon

[Gfellow]

A few years ago I became intrigued by articles reporting the discovery of stars very close to the purported Big Bang; 400 million years seems an awful short time for a star to evolve. Then more recently the discovery of 2nd generation - hydrogen, carbon stars - in the same proximity, supposedly in the same timeframe.
Now this article "Astronomers Have Detected 83 Black Holes in The Early Universe, Challenging Cosmology" (Well, not necessarily black holes, but definitely Quasars,) a mere 500 million years old.

"...This takes time, and requires copious amounts of matter. So how the heck did all these quasars pop up so early in the Universe's history?
"It is remarkable that such massive dense objects were able to form so soon after the Big Bang," said astrophysicist Michael Strauss of Princeton University.
"Understanding how black holes can form in the early Universe, and just how common they are, is a challenge for our cosmological models."..."

Could someone please give me a reasonable explanation as to how stars and quasars could evolve in such a short timespan?

 

[mathman]

My guess: the density of matter in the universe was high enough for gravity to make things happen.

 

[Drakkith]

400 million years seems an awful short time for a star to evolve.

Why's that?

 

[Gfellow]

Why's that?

Looked it up, yes indeed; proto-stars can form in a mere 50 million years according to present theory. I don't know what time span is necessary for second generation stars to form. How about Quasars?

 

[rootone]

A quasar is a would-be galaxy in which a central smbh has dominated gravity to the extent that almost all of the matter has either become consumed by the black hole, or is part of an enormous accretion disk. Stars can't form in such circumstances.

 

[ohwilleke]

The issue you identify is known as the Impossible Early Galaxy Problem and is an important unsolved question in lambda CDM cosmology. The abstract to the linked material states:

The current hierarchical merging paradigm and ΛCDM predict that the z∼4−8 universe should be a time in which the most massive galaxies are transitioning from their initial halo assembly to the later baryonic evolution seen in star-forming galaxies and quasars. However, no evidence of this transition has been found in many high redshift galaxy surveys including CFHTLS, CANDELS and SPLASH, the first studies to probe the high-mass end at these redshifts. Indeed, if halo mass to stellar mass ratios estimated at lower-redshift continue to z∼6−8, CANDELS and SPLASH report several orders of magnitude more M∼1012−13M⊙ halos than are possible to have formed by those redshifts, implying these massive galaxies formed impossibly early. We consider various systematics in the stellar synthesis models used to estimate physical parameters and possible galaxy formation scenarios in an effort to reconcile observation with theory. Although known uncertainties can greatly reduce the disparity between recent observations and cold dark matter merger simulations, even taking the most conservative view of the observations, there remains considerable tension with current theory.

Marie Martig summarized a recent paper that she wrote for the journal Nature Astronomy on one aspect of this problem (expanding on her 2009 PhD thesis) in a January 2018 article directed at the general public.

 

[phyzguy]

Looked it up, yes indeed; proto-stars can form in a mere 50 million years according to present theory. I don't know what time span is necessary for second generation stars to form. How about Quasars?

That 50 million year is in today's universe. In the early universe, as mathman said, the universe was much denser. At z=10, for example, the universe was about 1000 times denser than it is today. So massive stars probably formed through gravitational collapse much faster than they do today. Massive stars (100 solar masses or greater) only live a few million years before they explode in a supernova and their cores collapse to black holes. So black holes could have formed in as little as 10 million years. Also, in the dense early universe, maybe the first stars were much more massive than the ones we see today, and their death may have resulted in much more massive black holes. Once black holes are formed, they can grow by accreting the dense interstellar medium around them.

Another possibility is in the dense early universe, that large black holes could have formed through massive gas clouds that directly collapsed to form black holes.

We don't really know how these massive black holes formed in the first few hundred million years. But, as ohwilleke said, it is a problem that is being actively worked on, and there seem to be several possibilities. At this point, I don't think anyone can say, "it couldn't have happened that fast."