Model Breaking Records
That quasar in the news because of its distance/young age presents puzzles for cosmologists, and here is a nice summary from skyandtelescope.com, of the models and why they don't seem to fit. Although the quasar's distance is record setting, the blogger Shweta Krishnan reminds us, also, that the:
Quasar ....is not, however, the most distant object known in the deep sky. A gamma-ray burst has been identified at a redshift of 8.2, and a galaxy at a redshift of 8.6....The following are her words also--
....
The Conundrum within the Quasar
While the discovery offers unprecedented opportunities, it also presents a quandary in the form of the monstrous black hole that powers the quasar.
There are two dominant models of black-hole formation. A star the mass of 10-100 suns can go supernova to spawn these structures. A second theory suggests that accreting clumps of gases can directly undergo core collapse to generate supermassive black holes.
But both these models fail to explain how such an early black hole reached the mass of two billion suns. One possible explanation is a rapidly growing black hole that developed from the explosion of a star the size of half a million suns. But current theories cannot account for a star that size in the early universe. The same is true for large collapsing gas cores.
"This gives astronomers a headache," says Mortlock. "It's difficult to understand how a black hole a billion times more massive than the Sun can have grown so early in the history of the universe. It's like rolling a snowball down the hill and suddenly you find that it's 20 feet across!"
...
Black Hole theorist Priyamvada Natarajan (University of Yale), who spearheaded the model on self-regulating black holes, said that the discovery was exciting for the same reasons that it was challenging. She emphasized the need to find more giant black holes in order to come up with better models in the future. “The finding of a population is key to theoretical understanding (because) we can always come up with explanations for single rare objects, but to explain a population you need a robust mechanism.”
That quasar in the news because of its distance/young age presents puzzles for cosmologists, and here is a nice summary from skyandtelescope.com, of the models and why they don't seem to fit. Although the quasar's distance is record setting, the blogger Shweta Krishnan reminds us, also, that the:
Quasar ....is not, however, the most distant object known in the deep sky. A gamma-ray burst has been identified at a redshift of 8.2, and a galaxy at a redshift of 8.6....The following are her words also--
....
The Conundrum within the Quasar
While the discovery offers unprecedented opportunities, it also presents a quandary in the form of the monstrous black hole that powers the quasar.
There are two dominant models of black-hole formation. A star the mass of 10-100 suns can go supernova to spawn these structures. A second theory suggests that accreting clumps of gases can directly undergo core collapse to generate supermassive black holes.
But both these models fail to explain how such an early black hole reached the mass of two billion suns. One possible explanation is a rapidly growing black hole that developed from the explosion of a star the size of half a million suns. But current theories cannot account for a star that size in the early universe. The same is true for large collapsing gas cores.
"This gives astronomers a headache," says Mortlock. "It's difficult to understand how a black hole a billion times more massive than the Sun can have grown so early in the history of the universe. It's like rolling a snowball down the hill and suddenly you find that it's 20 feet across!"
...
Black Hole theorist Priyamvada Natarajan (University of Yale), who spearheaded the model on self-regulating black holes, said that the discovery was exciting for the same reasons that it was challenging. She emphasized the need to find more giant black holes in order to come up with better models in the future. “The finding of a population is key to theoretical understanding (because) we can always come up with explanations for single rare objects, but to explain a population you need a robust mechanism.”
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