That's awesome
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Very pronounced
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by drphilmarshall scientist, admin
No kidding! 😃 We tried modelling it a few years back and didn't get very far - it needs a fresh go I think! It appears in the middle of this paper: http://arxiv.org/abs/0904.1454 . I believe @gumbosea is taking a look at it too. Hopefully he'll have something to show us soon!
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So does the distance of the rings away from the cluster suggest the presence of dark matter? Just curious...
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by psaha scientist
The area inside the ring is proportional to (mass/distance). You can find a more precise formula in the wikipedia article on Einstein rings, but A = M/D in suitable units is about right.
For some lenses, the mass in stars (inferred from starlight) can account for the lensing mass. But for group lenses like this one, there isn't enough mass in the stars to do the lensing, it could only be dark matter.
By the way, I think @drphilmarshall is being too modest 😃 The models in his paper with de Xivry are pretty good. But @gumbosea has written a package that may do even better!
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Thanks for the info!
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by Thomas_J moderator
Nice find 😃
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