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Convert from Magnitude Density to Mass

  1. Sep 15, 2015 #1
    I have data which gives me the magnitude density (mag arcsec-2) of M31 as a function of radius. How can I convert this data to the (enclosed) mass at a given radius (for Velocity Curve analysis)?
  2. jcsd
  3. Sep 15, 2015 #2
    I don't know if it's a coincidence or not, but the magnitude density profile looks an awfully lot like a mass density profile:

    M31 Magnatude Profile.png

    Is there some very basic relation I'm not seeing or is this just a coincidence?
    Last edited: Sep 15, 2015
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