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Does Andromeda contain dark matter?

  1. Jan 8, 2007 #1
    Does Andromeda contain dark matter? Is the newly discovered halo able to account for the rotation of the galaxy?
  2. jcsd
  3. Jan 8, 2007 #2


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    Staff: Mentor

    quantum123, I deleted your duplicate post in the General Astronomy forum. Do not double-post. If you want your thread moved, PM a Mentor and we'll look into it.
  4. Jan 12, 2007 #3
    Not sure what you mean by "newly discovered halo", but Andromeda was the galaxy for which the first detailed flat rotation curve data was published.
  5. Jan 13, 2007 #4


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    Andromeda merely has about as much DM as our own galaxy . . . assuming cosmologists can be trusted.
  6. Jan 17, 2007 #5
    This means our galaxy has much bigger halo....? (as we have smaller baryonic matter radius)
    Same DM indicates that....we are having a bigger halo....
  7. Jan 19, 2007 #6
    What I mean is : Recently we discovered a lot of baryonic matter in the form of a halo around Andromeda galaxy which we did not otherwise know exist, and so needed to deduce the existence of dark matter to account for the gravitational and rotational effects of the entire galaxy. So with this discovery, do we still need to postulate the existence of dark matter for the Andromeda? Is the halo mass enough to account for the galaxy's motion?
  8. Jan 22, 2007 #7
    No, there is not enough baryonic matter in the extended halo of the Andromeda galaxy to account for it's rotation curve.
  9. Jan 23, 2007 #8
    Not enough baryonic matter in the objects like halo etc so far observed and discovered due to more detailed and accurate telescopic work. How about those not yet observed? The argument here is that the missing mass may just be yet to be discovered mass, and not dark matter. Instead of postulating some strange matter, why not just say some matter not discovered and observed yet, such as this latest halo? Why not just look harder with the telescope and you may just find another halo somewhere that can account for the flat rotation curve?
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