Closing the cosmological loop with the redshift drift

Understand

The redshift drift (also known as the Sandage Test) is a model-independent probe of fundamental cosmology, enabling us to watch the universe expand in real time, and thereby to confirm (or not) the recent acceleration of the universe without any model-dependent assumptions.

• On the other hand, by choosing a fiducial model one can also use it to constrain the model parameters, thereby providing a consistency test for results obtained with other probes.
• The drift can be measured by the Extremely Large Telescope and also by the full SKA.
• Recently two alternative measurement methods have been proposed: the cosmic accelerometer, and the differential redshift drift.