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The Physical Basis of the Tully-Fisher Relation
Simple scaling relations and dynamical arguments
- a pure exponential disk of central disk surface brightness I(0), and scale length rd, then
- mass internal to radius R is
- if the rotation curve flattens in the outer regions of the disk, then the total mass is:
- combining (a) and (b):
- Ld µ (Mtot/Ld) -2 Vmax 4 / I(0)
- If the dark matter halo is present so that the disk mass is Md = GMtot, then:
- Ld µ (Md/Ld) -2 G Vmax 4 / I(0)
-
Notes: