Recovering a redshift-extended VSL signal from galaxy surveys

Abstract

We investigate a new method to recover (if any) a possible varying speed of light (VSL) signal from cosmological data. It comes as an upgrade of [1,2], where it was argued that such signal could be detected at a single redshift location only. Here, we show how it is possible to extract information on a VSL signal on an extended redshift range. We use mock cosmological data from future galaxy surveys (BOSS, DESI, \emph{WFirst-2.4} and SKA): the sound horizon at decoupling imprinted in the clustering of galaxies (BAO) as an angular diameter distance, and the expansion rate derived from those galaxies recognized as cosmic chronometers. We find that, given the forecast sensitivities of such surveys, a $\sim 1\%$ VSL signal can be detected at $3\sigma$ confidence level in the redshift interval $z\in [0.,1.55]$. Smaller signals $(\sim 0.1\%)$ will be hardly detected (even if some lower possibility for a $1\sigma$ detection is still possible). Finally, we discuss the degeneration between a VSL signal and a non-null spatial curvature; we show that, given present bounds on curvature, any signal, if detected, can be attributed to a VSL signal with a very high confidence. On the other hand, our method turns out to be useful even in the classical scenario of a constant speed of light: in this case, the signal we reconstruct can be totally ascribed to spatial curvature and, thus, we might have a method to detect a $0.01$-order curvature in the same redhift range with a very high confidence.

12 pages, 4 figures

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Cited by in corpus (13)

• The minimally extended Varying Speed of Light (meVSL)
• A search for the variation of speed of light using galaxy cluster gas mass fraction measurements
• Consistency testing for invariance of the speed of light at different redshifts: the newest results from strong lensing and type Ia supernovae observations
• Constraining minimally extended varying speed of light by cosmological chronometers
• Testing a varying-$\Lambda$ model for dark energy within Co-varying Physical Couplings framework
• Measuring the speed of light with updated Hubble diagram of high-redshift standard candles
• 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
• Observational constraints on varying fundamental constants in a minimal CPC model
• Shadows of black holes at cosmological distances in the co-varying physical couplings framework
• Examining the validity of the minimal varying speed of light model through cosmological observations: relaxing the null curvature constraint
• A mechanism to generate varying speed of light via Higgs-dilaton coupling: Theory and cosmological applications
• New analysis of SNeIa Pantheon Catalog: Variable speed of light as an alternative to dark energy
• Revisiting the Constancy of the Speed of Light: Galaxy Cluster Mass Bias Implications