Testing the variation of fundamental constants by astrophysical methods: overview and prospects

TL;DR

This paper reviews astrophysical methods for testing the invariance of fundamental constants like alpha and mu, discussing current constraints, limitations, and future prospects with advanced telescopes and calibration techniques.

Contribution

It provides an overview of recent constraints on fundamental constants from astrophysical observations and discusses future improvements with next-generation instruments and calibration methods.

Findings

Current optical measurements have reached instrument sensitivity limits.

Radio observations require better molecular line standards and object selection.

Progress in optical and radio methods is quantified for future testing.

Abstract

By measuring the fundamental constants in astrophysical objects one can test basic physical principles as space-time invariance of physical laws along with probing the applicability limits of the standard model of particle physics. The latest constraints on the fine structure constant alpha and the electron-to-proton mass ratio mu obtained from observations at high redshifts and in the Milky Way disk are reviewed. In optical range, the most accurate measurements have already reached the sensitivity limit of available instruments, and further improvements will be possible only with next generation of telescopes and receivers. New methods of the wavelength calibration should be realized to control systematic errors at the sub-pixel level. In radio sector, the main tasks are the search for galactic and extragalactic objects suitable for precise molecular spectroscopy as well as high resolution laboratory measurements of molecular lines to provide accurate frequency standards. The expected progress in the optical and radio astrophysical observations is quantified.