A Understanding distances in Cosmology

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The discussion focuses on understanding various distance definitions in cosmology, specifically comoving distance, proper distance, and conformal time. The proper distance is expressed through integrals involving the Hubble parameter, with specific formulas provided for different redshifts. Conformal time is defined as the distance light travels from a distant galaxy to the observer, also represented by an integral of the Hubble parameter. There is uncertainty regarding the relationship between lookback time and conformal time. The conversation emphasizes the importance of accurate definitions for clarity in cosmological studies.
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I am trying to understand this graph but I am confused about the distance definitions. So there's an object located at a comoving distance ##r##.

The proper distance of the object at ##z'## can be written as
$$d(z{'}) = \frac{1}{1+z{'}}\int_0^{z{'}} \frac{dz{'}}{H(z{'})}$$

In this case,

$$d_1(z) = \frac{1}{1+z}\int_0^z \frac{dz}{H(z)}$$

and

$$d_0(z) = \int_0^z \frac{dz}{H(z)}$$

And we can also define the conformal time where it represents the distance taken by photon from the distant galaxy to us and can be written as

$$\eta(z) = \int_0^z \frac{dz}{H(z)}$$

There is also lookback time/distance but I am not sure it's same as the conformal time or not...

Are these definition that I have made are correct ?
 
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