Constraining a possible time-variation of the speed of light along with the fine-structure constant using strong gravitational lensing and Type Ia supernovae observations

• Published in: Journal of cosmology and astroparticle physics Vol. 2022; no. 8; pp. 62 - 78
• Main Authors: Colaço, L.R., Landau, S.J., Gonzalez, J.E., Spinelly, J., Santos, G.L.F.
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.08.2022
• Subjects: Bayesian reasoning; Dilatons; Galaxy distribution; Gravitational lenses; gravitational lensing; Light speed; Mass distribution; modified gravity; Red shift; Supernovae; supernovas
• ISSN: 1475-7516; 1475-7516
• DOI: 10.1088/1475-7516/2022/08/062

The possible time variation of the fundamental constants of nature has been an active subject of research since the large-number hypothesis was proposed by Dirac. In this paper, we propose a new method to investigate a possible time variation of the speed of light ( c ) along with the fine-structure constant ( α ) using Strong Gravitational Lensing (SGL) and Type Ia Supernovae (SNe Ia) observations. We assume a general approach to describe the mass distribution of lens-type galaxies, the one in favor of the power-law index model (PLAW). We also consider the runaway dilaton model to describe a possible time-variation of α . In order to explore the results deeply, we split the SGL sample into five sub-samples according to the lens stellar velocity dispersion and three sub-samples according to lens redshift. The results suggest that it is reasonable to treat the systems separately, but no strong indication of varying c was found.