Identify the appropriate reference frame for deceleration-parameter anisotropy

Identify the correct reference frame in which to analyze anisotropy in the deceleration parameter while preserving the observational information relevant to tilted cosmology.

Background

The thesis states that tilted cosmology predicts anisotropy in the locally measured deceleration parameter, but different possible frames—such as heliocentric, geocentric, galactic, and cosmological frames—lead to different treatments of observed redshifts and peculiar velocities. Resolving this issue is necessary for a reliable comparison between tilted-cosmology predictions and data.

References

However, a heated debate has arisen recently, as it remains unclear which frame of reference is appropriate for analyzing the data without losing important information.

— Cosmology without the cosmological principle: A study of the large-scale structure effects in the background universe  (2608.15983 - Pastén, 17 Aug 2026) in Chapter 11, Section “Future prospects,” subsection “The covariant formulation of gravity and its effects in Cosmology and LSS evolution,” item 4