But I think for this study it doesn't really matter. As long as all the galaxies are in the same coordinate system, they can calculate the relative distances between any two galaxies. And since they all came from the same sky survey, all the data was probably already in the same coordinate system.
https://en.wikipedia.org/wiki/Astronomical_coordinate_system...
But I think for this study it doesn't really matter. As long as all the galaxies are in the same coordinate system, they can calculate the relative distances between any two galaxies. And since they all came from the same sky survey, all the data was probably already in the same coordinate system.