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Did Black Holes appear in the first billion years?

  1. Jan 23, 2016 #1

    wolram

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    The tittle says it all really, how did Black Holes appear so early in the universe, why not stars?
    arXiv:1601.05473 [pdf, ps, other]
    The Early Growth of the First Black Holes
    Jarrett L. Johnson (LANL), Francesco Haardt (Universita dell'Insubria)
    Comments: 13 pages, 9 figures, invited review submitted to PASA
    Subjects: Astrophysics of Galaxies (astro-ph.GA); Cosmology and Nongalactic Astrophysics (astro-ph.CO)

    With detections of quasars powered by increasingly massive black holes (BHs) at increasingly early times in cosmic history over the past decade, there has been correspondingly rapid progress made on the theory of early BH formation and growth. Here we review the emerging picture of how the first massive BHs formed from the primordial gas and then grew to supermassive scales. We discuss the initial conditions for the formation of the progenitors of these seed BHs, the factors dictating the initial masses with which they form, and their initial stages of growth via accretion, which may occur at super-Eddington rates. Finally, we briefly discuss how these results connect to large-scale simulations of the growth of supermassive BHs over the course of the first billion years following the Big Bang.
     
  2. jcsd
  3. Jan 23, 2016 #2
    What this implies to me is that the initial accretions of matter following the very nearly uniform emergence of stable atoms must have been accretions of a very large scale.
    So extremely large in scale that direct collapse to black hole would be inevitable without any intermediate stages.
    In the Universe as it is today, such extremely large scale accretions would be very unlikely because now the Universe is filled with galaxies and clusters of galaxies whose collective gravitational effects would prevent such a very large accretion in one location from occurring.
    In the early universe those external gravity fields were not present, so there was nothing preventing extremely large scale accretion.
     
    Last edited: Jan 23, 2016
  4. Jan 23, 2016 #3

    wolram

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    Thank you for the reply Rootone, as i understand the universe was expanding rapidly in that era so how was accretion possible?
     
  5. Jan 24, 2016 #4

    wolram

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    Was this a stupid question?
     
  6. Jan 24, 2016 #5
    No it's not a stupid question, sorry to take a while getting back.
    My reply was just a reasoned guess based on intuition only.
    No external gravity fields = nothing to perturb really massive accretions from accumulating.

    While it seems true that the Universe has always been expanding, the inflation part (hypothetical but generally thought to be likely), lasted for a very short time.
    After that, while still expanding, the expansion had slowed to a rate that would allow gravity locally to be stronger than the overall expansion.
    After all that is the situation we have appear to have now. - expansion overall, but locally containing gravitationally bound systems which are not expanding.
     
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