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WIMPs
There have been many discussions here about WIMPs and searches for
them. Today's CfA Colloquium given by Dan Hooper of Fermilab offered a good overview of the subject. It's available at https://youtu.be/pPs_tvDYAl4 One note to viewers: the talk was interrupted by a fire alarm about half an hour in. It looks as though that has been edited out of the final video, so it should not be a problem. If there's a sudden jump, though, you'll know why. -- Help keep our newsgroup healthy; please don't feed the trolls. Steve Willner Phone 617-495-7123 Cambridge, MA 02138 USA |
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WIMPs
On Friday, 20 October 2017 06:50:35 UTC+2, Steve Willner wrote:
There have been many discussions here about WIMPs and searches for them. Today's CfA Colloquium given by Dan Hooper of Fermilab offered a good overview of the subject. It's available at https://youtu.be/pPs_tvDYAl4 Doing a search with "annihilating dark matter" I found this: https://fermi.gsfc.nasa.gov/science/...14A_Hooper.pdf "Dark matter annihilating in the galactic center" I also found this: https://arxiv.org/abs/1403.4495 "Dark matter Annihilation in the Universe" Which describes this annihilation process (shortly after the Big Bang?) The Hooper 2017 talk also discusses millisecond pulsars A search with "millisecond pulsars dark matter" I found this: https://futurism.com/dark-matter-hop...lactic-center/ Which reads: "New analysis by U.S. and European teams indicates that the excess of gamma rays emanating from the center of the galaxy probably comes from pulsars, not dark matter." Also this: https://journals.aps.org/prl/abstrac...ett.116.051102 "Strong Support for the Millisecond Pulsar Origin of the Galactic Center GeV Excess" This still raises the question: Which is the best explanation that the observed galaxy rotation curves (in general) do not match the calculated curves based on visible (baryonic) matter? Nicolaas Vroom |
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WIMPs
In article ,
Nicolaas Vroom writes: Which is the best explanation that the observed galaxy rotation curves (in general) do not match the calculated curves based on visible (baryonic) matter? Depends on whom you ask. MOND enthusiasts will say MOND, dark-matter enthusiasts will say dark matter. I think that the MOND people are right when they say that conventional dark matter requires a very unnatural distribution in order to explain the observations. For example, there is a very tight correlation between luminosity and velocity dispersion, but the luminosity comes only from stars while the velocity dispersion is influenced by dark-matter halos orders of magnitude larger in size. On the other hand, we shouldn't be surprised that we don't know all the contents of the universe, and while phenomenologically it works well, it is difficult to fit MOND in with the rest of physics. Also, even MOND enthusiasts admit that dark matter works well on cosmological scales. I think that dark-matter enthusiasts should investigate MOND phenomenology more. Recently, unconventional dark matter, which behaves like standard dark matter in a cosmological context and MOND-like on galaxy scales looks like a promising development. Look for papers by Justin Khoury. |
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