Constraints on the variation of fine structure constant from joint SPT-SZ and XMM-Newton observations

Abstract

We search for a variation of the electromagnetic fine structure constant (α ≡ e2/ℏ c) using a sample of 58 SZ selected clusters in the redshift range (0.2<z<1.5) detected by the South Pole Telescope, along with X-ray measurements using the XMM-Newton observatory. We use the ratio of the integrated SZ Compto-ionization to its X-ray counterpart as our observable for this search. We first obtain a model-independent constraint on α of about 0.7%, using the fact that the aforementioned ratio is constant as function of redshift. We then look for logarithmic dependence of α as a function of redshift: Δ α/α = −γ ln (1+z), as this is predicted by runaway dilaton models. We find that γ = −0.046 ± 0.1, which indicates that there is no logarithmic variation of α as a function redshift. We also search for a dipole variation of the fine structure constant using the same cluster sample. We do not find any evidence for such a spatial variation.

Probing the Time Variation of a Fine Structure Constant Using Galaxy Clusters and the Quintessence Model

“…In this way, the intrinsic uncertainty σ int for the SPT sample depends on the dispersion of angular diameter distance D A and thus is affected by the uncertainties of the cosmological parameters (i.e., H 0 and Ω m ) indirectly. Our analyses show no significant evidence for the fine structure constant α varying with redshift, consistent with previous galaxy cluster-based results (Galli 2013;Colaço et al 2019;Bora & Desai 2021a. The constant C was found to approach unity sufficiently, indicating that the isothermal temperature profile is universal for describing galaxy clusters.…”

“…should be a constant independent of redshift. This ratio has been used to explore the variation of α (Galli 2013;Holanda et al 2016b;Colaço et al 2019;Bora & Desai 2021a, which is also our main focus in this paper.…”

“…, and indirectly constrain Δα/α by constraining γ. Most of this kind of work employed the observations of the Sunyaev-Zel'dovich effect (SZ effect, hereafter) combined with observations of the X-ray surface brightness of galaxy clusters, for which the former can be characterized by the integrated Comptonization parameter Y D A SZ 2 and the latter by the Y X parameter (Holanda et al 2017(Holanda et al , 2016a(Holanda et al , 2016bColaço et al 2019;Bora & Desai 2021a. Alternatively, Colaço et al (2021aColaço et al ( , 2021b used combined measurements of strong gravitational lensing systems and Type Ia supernovae to constrain γ.…”

“…An analytical form of P(r) is needed to calculate the integrations in Equations (27-28), for which we adopt the universal pressure profile suggested byArnaud et al (2010). FollowingBora & Desai (2021a), we set R b = 10R 500 . Since the SPT observation gave Y SZ values in terms of an aperture of ¢ 0…”

Gravitational lens time-delay as a probe of a possible time variation of the fine-structure constant

“…Several other tests capable of probing such temporal variation of α with galaxy cluster observations have been emerging since then (see e.g. [42][43][44] and references therein).…”