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Thread: calculating redshift

  1. #1 calculating redshift 
    Forum Freshman
    Join Date
    Dec 2008
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    can anyone list the calculations for working out the redshift?

    Distance = 200 Mpc

    Hubble constant = H0 = 73 km s1 Mpc-1?

    Speed of light c = 3.0 105 km s1


    Do I need to convert something first?


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  3. #2  
    Moderator Moderator Dishmaster's Avatar
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    You need the cosmological model as well. You can play around with the constants on this or that website. Assuming




    you need a redshift value of



    to be consistent with 200 Mpc. Note that this assumption is based on a flat universe with . Other geometries are also possible changing the distance vs. redshift relation considerably.

    A simple calculation can be done with the following assumptions:




    With being the distance. Then you get:



    You see that these simple assumptions give you the right magnitude of the redshift value, but not the correct value.


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