Examining the validity of the minimal varying speed of light model through cosmological observations: relaxing the null curvature constraint

Understand

We revisit a consistency test for the speed of light variability, using the latest cosmological observations.

• This exercise can serve as a new diagnostics for the standard cosmological model and distinguish between the minimal varying speed of light in the Friedmann-Lema\^{i}tre-Robertson-Walker universe.
• We deploy Gaussian processes to reconstruct cosmic distances and ages in the redshift range $0<z<2$ utilizing the Pantheon compilation of type-Ia supernova luminosity distances (SN), cosmic chronometers from differential galaxy ages (CC), and measurements of both radial and transverse modes of baryon acoustic oscillations ($r$-BAO and $a$-BAO) respectively.
• Such a test has the advantage of being independent of any non-zero cosmic curvature assumption - which can be degenerated with some variable speed of light models - as well as any dark energy model.