Galaxy cluster constraints on the coupling to photons of low-mass scalars

TL;DR

This paper investigates how light scalar fields coupled to photons affect galaxy cluster observations, deriving new astrophysical bounds on such couplings that complement existing laboratory and cosmological constraints.

Contribution

It introduces new bounds on photon-scalar couplings from galaxy cluster turbulence effects, considering both conformal and disformal interactions, expanding the understanding of scalar field impacts on astrophysical phenomena.

Findings

New bounds on photon-to-scalar couplings from galaxy cluster data

Constraints on conformal and disformal scalar interactions

Complementary limits to laboratory experiments

Abstract

We consider a broad class of interactions between radiation and a light scalar field, including both conformal and disformal couplings. Such a scalar field potentially acts on cosmological scales as dark energy and could also appear in modified gravity theories. We study the consequences of these couplings on the mixing between the scalar field and photons in galaxy clusters in the presence of a magnetic field. In particular we focus on the resulting turbulence-induced irregularities in the X-ray and UV bands. We find new bounds on the photon-to-scalar couplings, both conformal and disformal, which complement laboratory experiments and other astrophysical constraints.