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We investigate whether there are any cosmological evidences for a scalarfield with a mass and coupling to matter which change accordingly to theproperties of the astrophysical system it "lives in", without directly focusingon the underlying mechanism that drives the scalar field scale-dependentproperties. We assume a Yukawa type of coupling between the field and matterand also that the scalar field mass grows with density, in order to overcomeall gravity constraints within the solar system. We analyse three differentgravitational systems assumed as "cosmological indicators": supernovae type Ia,low surface brightness spiral galaxies and clusters of galaxies. Results showthat: a) a quite good fit to the rotation curves of low surface brightnessgalaxies only using visible stellar and gas mass components is obtained; b) ascalar field can fairly well reproduce the matter profile in clusters ofgalaxies, estimated by X-ray observations and without the need of anyadditional dark matter; c) there is an intrinsic difficulty in extractinginformation about the possibility of a scale-dependent massive scalar field (ormore generally about a varying gravitational constant) from supernovae type Ia.

Testing feasibility of scalar-tensor gravity by scale dependent mass and coupling to matter