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Planck mass dark matter?

  1. Jun 2, 2015 #1
    I've been reading about black holes and dark matter and came across this theory: http://www.nature.com/nature/journal/v329/n6137/abs/329308a0.html where black holes don't completely evaporate, but evaporate until it hits an equilibrium where it's both unable to evaporate anymore (making it stable for the age of the universe) as well as not being able to absorb anything, making it completely non-interactive with light.

    I've read that primordial black holes have been dropped as a candidate for dark matter: http://www.nature.com/news/search-for-primordial-black-holes-called-off-1.14551 but this article mentions black holes the size of the moon.

    Wouldn't the majority of primordial black holes have been tiny?
     
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  3. Jun 3, 2015 #2

    marcus

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    Hi Runner, I'm only responding to one part of your post, you raised an interesting question about the range of masses of primordial BH too.
    And about current thinking as to what part they could play in DM. I hope we get some response!

    But this first article you cite is from 1987. It is going to be hard to find other articles that cited it, and discussed its claims.


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    Nature 329, 308 - 309 (24 September 1987); doi:10.1038/329308a0
    Can Planck-mass relics of evaporating black holes close the Universe?
    J. H. MACGIBBON

    I'll go look up the author and see if he has something more recent that might be on arXiv.org. arXiv goes back to early 1990s.
    Do you happen to have a link to something more recent?
     
  4. Jun 3, 2015 #3

    marcus

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    Here we go. the author is Jane H MacGibbon and here are her physics papers
    http://arxiv.org/find/grp_physics/1/au:+Macgibbon/0/1/0/all/0/1
    There are 25 papers going back to 1992, on arXiv.
    She does not seem to have pursued that 1987 idea. I wonder why she abandoned it?
    But there is a 2015 paper by her on primordial black holes! Let's see what she says nowadays.
    http://arxiv.org/abs/1503.01166
    Primordial Black Holes
    Jane H MacGibbon, Tilan N. Ukwatta, J.T. Linnemann, S.S. Marinelli, D. Stump, K. Tollefson
    (Submitted on 3 Mar 2015)
    Primordial Black Holes (PBHs) are of interest in many cosmological contexts. PBHs lighter than about 1012 kg are predicted to be directly detectable by their Hawking radiation. This radiation should produce both a diffuse extragalactic gamma-ray background from the cosmologically-averaged distribution of PBHs and gamma-ray burst signals from individual light black holes. The Fermi, Milagro, Veritas, HESS and HAWC observatories, in combination with new burst recognition methodologies, offer the greatest sensitivity for the detection of such black holes or placing limits on their existence.
    Comments: 2014 Fermi Symposium proceedings

    It looks like she has given up on the idea that there are quiet remnants. The gamma-ray burst signal is an end-of-life explosion when the BH gets hotter and hotter as it approaches zero mass and evaporates faster and faster. It is completely annihilated in a final burst or flare. This is the standard
    picture of Hawking evaporation. It leaves no remnant.

    I think we have to find some other authors who have ideas about BH evaporation ending up with a remnant that could (if numerous enough) contribute to DM. The idea is certainly out there. I remember Leonardo Modesto and Sabine Hossenfelder were playing around with it a few years ago. But they seem to have abandoned it too. Haven't heard anything about it from them in the past 2 or 3 years.

    Have to find some professional researcher who is actively engaged with this idea of DM and who ties up the loose ends (like why doesn't evaporation continue to zero in the accepted Hawking way? and how come there are so many PBH when we haven't detected any signs of PBH, what could have formed this huge amount of quiet PBH but only ones we can't detect and not some still radiating variants that we can?
    So much to explain! Hardly anybody seems to be currently taking the idea seriously that DM could be quiet remnant micro PBH.

    You could look up Modesto's papers and then see who has CITED THEM recently and check out what they have to say. Hopefully some other people will comment and can suggest other names and maybe provide links. (I kind of suspect that basically it is a dead idea though.)
     
  5. Jun 3, 2015 #4

    Chronos

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    PBH mass constraints have pretty much eliminated them as dark matter candidates. In addition to the paper cited by Marcus, there is also; http://arxiv.org/abs/1401.3025, Tidal capture of a primordial black hole by a neutron star: implications for constraints on dark matter and http://arxiv.org/abs/1209.6021, Constraints on primordial black holes as dark matter candidates from star formation. PBH's in the mass range of 10^9 through 10^17 gms is constrained by big bang nucleosynthesis as noted in http://arxiv.org/abs/0912.5297, New cosmological constraints on primordial black holes, which forbids abundance sufficient to account for the dark matter fraction of the universe. Since smaller PBH's would produce unaccecptably high contributions to the cosmic gamma ray background, eliminating PBH's in the range above 10^17 g basically closes the door on PBH's as a major contributor to the dark matter fraction of the universe.
     
    Last edited: Jun 3, 2015
  6. Jun 3, 2015 #5
    I have heard this question posited by others, and I am curious as to why PBH would be limited in size. If the pressure and temperature were optimal (as during the Hadron Epoch or before), would not PBH manifest themselves in every possible size, from micro- to super-massive? Why would PBH be limited in mass?
     
  7. Jun 3, 2015 #6

    Chronos

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    PBH mass is largely irrelevant, we can rule them out as DM candidates over a large range of masses. They would have astrophysical consequences that are not observed
     
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