Quasars as indicators of distance?

[DJ-Smiles]

I have been doing some thinking about quasars and have been wondering. Are we able to sue the redshift of a quasar to find out the distance of a galaxy?

If we know the redshift at a galaxy can't we just use Vrecession= (c*(λ-λo))/(λo), then substitute this value into Vrecession=Hubble's constant *Distance and rearrange to find the distance?

Am I correct in this assumption or am I way off, any feedback would be greatly appreciated, thanks.

DJ

 

[NascentOxygen]

I have been doing some thinking about quasars and have been wondering. Are we able to sue the redshift of a quasar to find out the distance of a galaxy?

If we know the redshift at a galaxy can't we just use Vrecession= (c*(λ-λo))/(λo), then substitute this value into Vrecession=Hubble's constant *Distance and rearrange to find the distance?

It's a long time since I studied anything astronomic, so I can't say much here. What you say would produce a number, but won't distance calculations based on red shift be flummoxed by the quasar's own velocity?

From wikipedia we read:

It should be noted that quasars that have a recessional velocity greater than the speed of light (c) are very common. Any quasar with z>1 is going away from us in excess of c. Early attempts to explain superlumic quasars resulted in convoluted explanations with a limit of z=2.326, or in the extreme z<2.4. z=1 means a redshift indicating travel away from us at the speed of light. The majority of quasars lie between z=2 and z=5 .

 

[DJ-Smiles]

Hmm yeah that is a good point.

 

[phinds]

Are we able to sue the redshift of a quasar to find out the distance of a galaxy?

I think it would be difficult to find a lawyer who would take the case.

 

[NascentOxygen]

A method based on lensing for estimating the distance to a quasar, see method X here: http://www.astro.ucla.edu/~wright/distance.htm