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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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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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