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Galaxy Rotation Curve problem -

  1. Jan 31, 2010 #1
    Hi folks,

    I'm supposed to derive the func. form of the rotation curve for the outer parts of our galaxy, in the absence of dark matter.

    Im assuming that I treat this as a linear curve, since in reality, dark matter flattens out the curve, when it should continue following the linear(?)

    What I've done:

    1) v= rw v = Vel, r = distance from centre w = angular freq. (d(theta)/dt)
    2) v²/r = GM(r)/r²

    What do I do now? If I subs. 1 into 2, I get stuck with w and M(r).

    How am I supposed to treat M(r): (M(r) = [(4/3)*Pi*r³]*p)
    Do I just introduce p (density) into the eqn. and assume p is constant?
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
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