| Topic: |
Science > Physics |
| User: |
"Old Man" |
| Date: |
21 Sep 2003 07:45:53 PM |
| Object: |
Correlation Between Dark Matter & Bright Matter ? |
For galaxies in the Ursa Major group, it is found that spiral galaxy
apparent luminosity, L, is related to peak stellar tangential velocity,
V_max (from spectral Doppler shift), by
L = L0 (V_max)^4 (Tully - Fisher relation)
Where L0 is a constant. On the left hand side of the equation, L
gives a measure of the visible matter in a galaxy, while, on the right
hand side, V_max yields a measure of the total matter, including
dark matter, in that galaxy wherein the majority (~ 75 %) of galactic
matter is found to be dark matter. In other words, the amount of
dark matter in a galaxy is tied to the amount of visible matter in
that galaxy. Maybe dark matter isn't so strange after all.
Reference:
"Galaxies in the Universe" (2000) LS Sparke & JS Gallagher
ISBN 0 521 59740 4
Its a great book! [Old Man]
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| User: "Sam Wormley" |
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| Title: Re: Correlation Between Dark Matter & Bright Matter ? |
22 Sep 2003 07:10:52 AM |
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Old Man wrote:
For galaxies in the Ursa Major group, it is found that spiral galaxy
apparent luminosity, L, is related to peak stellar tangential velocity,
V_max (from spectral Doppler shift), by
L = L0 (V_max)^4 (Tully - Fisher relation)
Where L0 is a constant. On the left hand side of the equation, L
gives a measure of the visible matter in a galaxy, while, on the right
hand side, V_max yields a measure of the total matter, including
dark matter, in that galaxy wherein the majority (~ 75 %) of galactic
matter is found to be dark matter. In other words, the amount of
dark matter in a galaxy is tied to the amount of visible matter in
that galaxy. Maybe dark matter isn't so strange after all.
Reference:
"Galaxies in the Universe" (2000) LS Sparke & JS Gallagher
ISBN 0 521 59740 4
Its a great book! [Old Man]
Thanks Old Man!
-Sam
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