How real-time cosmology can distinguish between different anisotropic models

TL;DR

This paper explores how future high-resolution astrometric surveys could differentiate between isotropic and anisotropic cosmological models by analyzing quasar displacements over time, highlighting the need for advanced resolution to detect specific anisotropic signatures.

Contribution

It demonstrates that next-generation surveys with improved resolution can distinguish between isotropic and certain anisotropic models, and potentially rule out large local void models.

Findings

GAIA's current resolution is insufficient for this purpose within ten years.

A survey with 0.1 micro-arcsecond resolution could detect rotating anisotropic models.

Detection of such anisotropies would exclude large local void models.

Abstract

We present a new analysis on how to distinguish between isotropic and anisotropic cosmological models based on tracking the angular displacements of a large number of distant quasars over an extended period of time, and then performing a multipole-vector decomposition of the resulting displacement maps. We find that while the GAIA mission operating at its nominal specifications does not have sufficient angular resolution to resolve anisotropic universes from isotropic ones using this method within a reasonable timespan of ten years, a next-generation GAIA-like survey with a resolution ten times better should be equal to the task. Distinguishing between different anisotropic models is however more demanding. Keeping the observational timespan to ten years, we find that the angular resolution of the survey will need to be of order 0.1 micro-arcsecond in order for certain rotating anisotropic models to produce a detectable signature that is also unique to models of this class. However, should such a detection become possible, it would immediately allow us to rule out large local void models.