An influence of the matter distribution on the positional accuracy of reference sources

TL;DR

This paper investigates how the non-stationary gravitational field of the Galaxy affects the apparent positions of extragalactic sources, considering both visible and hidden matter, and models the resulting light deflection as a stochastic process.

Contribution

It introduces a stochastic model for light deflection caused by galactic matter, including baryonic and hidden components, and analyzes the autocorrelation of positional variations over time.

Findings

Relative changes in deflection angle are about 15% over one year.

Relative changes increase to about 35% over ten years.

The stochastic process model captures the variability in source positions due to galactic matter.

Abstract

We consider an influence of a non-stationary gravitational field of the Galaxy on the visible positions of extragalactic sources. A contribution of the baryonic component of the galactic matter as well as of the hidden matter (including a population of brown dwarfs) were took into account. The observed variations of the deflection angle of light rays in a gravitational field of randomly moving point-like masses can be considered as a stochastic process. Using such an approach we constructed an autocorrelation function of studied stochastic process and found that its relative changes are about 15% for one year and about 35% for ten years.