|
Given that the degree of lensing will be both a function of the mass and the expansion of space, how on Earth do you differentiate between the two? I would have thought that the mass of the dark matter would be estimated from the lensing but if this has an expansion component then the mass estimate is going to be somewhat unknown. Do we know enough about the visual galaxy components of Abell 1689 (e.g. relative motions) to estimate the mass of the dark matter?
Regards, Rob.
|