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A recent arXiv article measures the variation of gravitational potential in a local region around the solar system, and from that it tries to infer the mass density. Are there any valid counterarguments to their conclusion, i.e: that there is no dark matter near our vicinity?

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Not my field, so I won't write a full-on answer, but I believe that the dark matter distribution is allowed to be lumpy on the stellar neighborhood scale. –  dmckee Apr 19 '12 at 22:18

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The article presents some seemingly very interesting results that definitely don't seem to mesh with the standard model of things. There hasn't been time for any big responses to come out, but there are a few things that stood out to me from their article. Note, I haven't checked any of their calculations personally---I want to hear what the real experts say about it first.

  • The dark matter 'halo' is much more extensive than the distribution of stars in the galaxy. Because of this, the effect of the dark matter (as close as the sun is to the galactic center) is expected to be quite small. Its hard to believe they were able to get sensitive enough results using proper-motions to achieve the confidence interval they report.

  • The entire argument hinges on the disk of the milky-way galaxy being in hydrostatic equilibrium, with a well-known distribution of baryonic matter. There was a paper out a while ago challenging the entire concept of hydrostatic equilibrium in the disk---I'm not sure what popular opinion is on that article (but it seemed a little far-fetched). The baryonic (i.e. normal) matter distribution is also only known so well, even in the solar neighborhood---again making it seem very difficult to obtain such a high confidence result.

Its a really interesting paper; and off the top of my head... its really hard to think of any way to reconcile their results (if they're true) with the standard model of dark-matter halos. This is definitely something worth paying attention too.

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