Probing variation of the fine-structure constant in runaway dilaton models using Strong Gravitational Lensing and Type Ia Supernovae

In order to probe a possible time variation of the fine-structure constant (alpha), we propose a new method based on Strong Gravitational Lensing and Type Ia Supernovae observations. By considering a class of runaway dilatonmodels, where Delta a/alpha = -gamma ln (1 + z), we obtain constraints on Delta alpha/alpha at the level. gamma similar to 10(-2) (gamma captures the physical properties of the model). Since the data set covers the redshift range 0.075 <= z <= 2.2649, the constraints derived here provide independent bounds on a possible time variation of alpha at low, intermediate and high redshifts.

Automated summary

A new method based on Strong Gravitational Lensing and Type Ia Supernovae observations is proposed to investigate a possible time variation of the fine-structure constant (alpha). Constraints on Delta alpha/alpha are obtained by considering a class of runaway dilaton models, providing independent bounds on a possible time variation of alpha at low, intermediate, and high redshifts within the redshift range covered by the data set.