An Extension of the IAU Framework for Reference Systems

TL;DR

This paper discusses extending the IAU reference system framework to incorporate recent advances in observational and computational technologies, focusing on space-time transformations, PPN parameters, and cosmological reference frames.

Contribution

It proposes new directions for theoretical development of the IAU reference system framework to better align with modern observational and computational progress.

Findings

Enhanced understanding of space-time transformations.

Analysis of PPN parameters and gauge invariance.

Application of reference frames to cosmology.

Abstract

IAU 2000 resolutions on the reference frames set up a solid theoretical foundation for implementing general relativity in astronomical data processing algorithms and for unambiguous interpretation of measured relativistic effects. We discuss possible directions for further theoretical development of the IAU resolutions aimed to take into account the decadal progress in observational techniques and computer-based technologies. We address the following subjects: 1) space-time transformations and the structure of the metric tensor; -2) PPN parameters and gauge invariance of equations of motion; -3) astronomical reference frames for cosmological applications.