Analytical approaches to the study of the phase of the visibility function

TL;DR

This paper investigates how the phase of the visibility function in radio interferometry depends on the projection of the baseline and direction, especially for space-based bases up to six Earth diameters, revealing universal behaviors for small baselines.

Contribution

It provides an analytical description of the phase dependence on baseline projection and direction, extending understanding for space-based radio interferometry.

Findings

Phase dependence has a universal character for small baseline projections.

Results align with numerical magnetohydrodynamic models.

Analytical expressions for phase dependence are derived.

Abstract

In radio interferometric observations, the main source of information is the complex visibility function, which includes amplitude and phase. In this paper, the dependence of the phase of the visibility function on the base projection is investigated when used in radio interferometry with space bases up to six Earth diameters. The dependence of the phase of the visibility function on the projection of the base and direction is obtained. It is shown that for small values of the base projections, this dependence has a universal character and is consistent with the results of numerical magnetohydrodynamic models.