Are there any observations that more distant galaxies appear to rotate more slowly than closer galaxies?
What methods are used to measure the rotational speed of galaxies? (both orbital speed profiles and/or bulk average rotation speed)
What is the current limit for how far away a galaxy can be to make such measurements?
I greatly appreciate any answer or links to info on this topic. I am not an astronomer by profession or education, just deeply fascinated with cosmology.