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Dark Matter Distribution Around Galaxies

  1. Sep 16, 2010 #1
    I saw an interesting video that showed the dark matter halo that exists around the milky way galaxy, the scientist described it as having a squashed beached ball sort of shape, which got me thinking. Is there any reason why galactic black holes might have something to do with dark matter creation? The squashed beachball of dark matter sort of looks like what I would expect say field lines coming out of a pulsar to look like or something.

    I guess what I'm getting at is, a rotating neutron star produces a magnetic field around it in something like a squashed beachball shape, is it plausible that the concentration of dark matter in squashed beachball shaped halos around galaxies have something to do with galactic black holes? Perhaps besides shooting out gamma rays they also shoot out strange particles that are only affected by gravity (dark matter)? I wish I knew more about the subject matter, but to me, the shape of the dark matter halo around the milky way really makes it look analogous to the shape of say magnetic field lines around a stellar body.

    http://www.astronomy.ohio-state.edu/~ryden/ast162_5/pulsar.gif looks similar to
  2. jcsd
  3. Sep 17, 2010 #2


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    Highly unlikely. The black holes at the centers of galaxies typically make up only a fraction of a percent to a couple percent of the total galaxy's mass, while the dark matter is typically around five to ten times as massive as all of the normal matter in the galaxy (including both stars and dust).

    Furthermore, we see evidence of dark matter in the cosmic microwave background (CMB), which was emitted before any astrophysical black holes would have formed. Nobody has ever proposed, to my knowledge, a viable mechanism by which black holes could produce dark matter. Some have proposed that black holes could be dark matter, but that's ruled out by a number of different observations, including the CMB evidence.

    Anyway, an elliptical shape is what we tend to expect from a bunch of non-interacting matter that falls into a potential well.
  4. Sep 17, 2010 #3
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