Cosmological implications of the anisotropy of ten galaxy cluster scaling relations

Understand

The hypothesis that the late Universe is isotropic and homogeneous is adopted by most cosmological studies.

• The expansion rate $H_0$ is thought to be spatially constant, while bulk flows are often presumed to be negligible compared to the Hubble expansion, even at local scales.
• Their effects on the redshift-distance conversion are hence usually ignored.
• Any deviation from this consensus can strongly bias the results of such studies and thus the importance of testing these assumptions cannot be understated.