Sunday, January 7, 2018

astrophysics - Distance from redshift


I am looking for a exact derivation of a relation between redshift z and distance d.


What I know is the definition z=λobservedλunshifted1=1+vc1vc1

and that the Hubble constant H as a function of z is: H2=H20(Ωm(1+z)3+ΩΛ)


How can I use this to derive the distance?




Answer



Depending on the shape of the universe the luminosity distance is given by :


dL(z)={(1+z)cH0|Ωk|sin[|Ωk|z0dzH(z)/H0]for k=1(1+z)cH0z0dzH(z)/H0for k=0(1+z)cH0|Ωk|sinh[|Ωk|z0dzH(z)/H0]for k=1


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