Does Andromeda contain dark matter?

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Discussion Overview

The discussion centers on the presence of dark matter in the Andromeda galaxy, particularly in light of a recently discovered halo of baryonic matter. Participants explore whether this halo is sufficient to explain the galaxy's rotation without invoking dark matter.

Discussion Character

  • Debate/contested
  • Exploratory
  • Technical explanation

Main Points Raised

  • Some participants question the necessity of dark matter in Andromeda, suggesting that the newly discovered halo of baryonic matter could account for the galaxy's rotation.
  • Others assert that there is not enough baryonic matter in the halo to explain the observed rotation curve of Andromeda.
  • A participant proposes that the missing mass could simply be undiscovered matter rather than dark matter, advocating for further observational efforts to identify additional halos.
  • There is a mention of Andromeda's dark matter content being comparable to that of the Milky Way, though this is contingent on the trustworthiness of cosmological models.

Areas of Agreement / Disagreement

Participants express differing views on the role of dark matter in Andromeda, with no consensus reached on whether the newly discovered halo can fully account for the galaxy's rotation. The discussion remains unresolved regarding the necessity of postulating dark matter.

Contextual Notes

Some claims depend on the definitions of baryonic matter and dark matter, and the discussion acknowledges the limitations of current observational capabilities in identifying all relevant mass components.

quantum123
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Does Andromeda contain dark matter? Is the newly discovered halo able to account for the rotation of the galaxy?
 
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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.
 
quantum123 said:
Does Andromeda contain dark matter? Is the newly discovered halo able to account for the rotation of the galaxy?

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.
 
Andromeda merely has about as much DM as our own galaxy . . . assuming cosmologists can be trusted.
 
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...
 
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?
Thanks.
 
No, there is not enough baryonic matter in the extended halo of the Andromeda galaxy to account for it's rotation curve.
 
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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