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Thread: Luminosity distance

  1. #1 Luminosity distance 
    Forum Bachelors Degree PetTastic's Avatar
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    Elsewhere, I am having a few slightly heated discussions about how to calculate the Luminosity distance as a function of z, for an alternative cosmology.
    The Wikipedia page "Luminosity distance - Wikipedia, the free encyclopedia" gets a bit complicated very quickly for the BBT version.

    I was assuming that if I have a function distance(z) and function photonRate(z) (photon rate decreases with z)
    Then Luminosity distance is just: distance(z)/photonRate(z)



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    Could you give an argument as to why you think this equation is appropriate?


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    Forum Bachelors Degree PetTastic's Avatar
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    Quote Originally Posted by PhysBang View Post
    Could you give an argument as to why you think this equation is appropriate?
    Yes, but it does not work

    I got a mail pointing out my silly mistake within minutes of posting.
    If photonRate(z) return 0.25 it only makes the object look twice the distance not 4 times.

    Edit---
    Double oops, there is also photonEnergy(z)
    Basicaly I made a right mess of the post when trying to remove all the none standard cosmolgy crap into functions.
    DL = distance(z)/((photonRate(z)*photonEnergy(z))^0.5)
    The real question is does the angular size come into it?
    Last edited by PetTastic; October 6th, 2011 at 12:58 PM.
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