Constraints on a possible variation of the fine structure constant from galaxy cluster data

TL;DR

This paper introduces a new method using galaxy cluster data to constrain potential variations in the fine structure constant, linking it to distance-duality violations, and provides initial bounds at low to intermediate redshifts.

Contribution

It presents a novel approach combining X-ray and Sunyaev-Zeldovich measurements to probe alpha variation through galaxy cluster gas mass fractions.

Findings

Constraints on alpha variation from 29 galaxy clusters.

Method links alpha variation to distance-duality violations.

Future surveys can improve these constraints.

Abstract

We propose a new method to probe a possible time evolution of the fine structure constant $\alpha$ from X-ray and Sunyaev-Zeldovich measurements of the gas mass fraction ($f_{gas}$) in galaxy clusters. Taking into account a direct relation between variations of $\alpha$ and violations of the distance-duality relation, we discuss constraints on $\alpha$ for a class of dilaton runaway models. Although not yet competitive with bounds from high-$z$ quasar absorption systems, our constraints, considering a sample of 29 measurements of $f_{gas}$, in the redshift interval $0.14 < z < 0.89$, provide an independent estimate of $\alpha$ variation at low and intermediate redshifts. Furthermore, current and planned surveys will provide a larger amount of data and thus allow to improve the limits on $\alpha$ variation obtained in the present analysis.