Gravitational_lensing_sky_observations

[es111]

In observational comsology how can we sure that the oberved objects (galaxies) are all distinct and not (for many ?) a different image of the same source via the gravitational lensing effect ? Thanks. ES111

[swansont]

In observational comsology how can we sure that the oberved objects (galaxies) are all distinct and not (for many ?) a different image of the same source via the gravitational lensing effect ? Thanks. ES111

 

 

They have to be an image of the same thing to be a candidate for lensing. Galaxies with different different shapes would not be. Different spectral signatures, too. Different recession speeds/redshifts.

[AbstractDreamer]

Not only that, with anisotropic expansion around gravity wells, superluminal galactic recession velocities, local (peculiar) spacetime curvature and gravitational lensing; it is possible that some images are of the same galaxy but viewed from the complete opposite direction (relative to observer and object)!?

Edited December 8, 2016 by AbstractDreamer