Abstract
In its weak field limit, Scalar-tensor-vector gravity theory introduces a Yukawa-correction to the gravitational potential. Such a correction depends on the two parameters, α which accounts for the modification of the gravitational constant, and μ⁎−1 which represents the scale length on which the scalar field propagates. These parameters were found to be universal when the modified gravitational potential was used to fit the galaxy rotation curves and the mass profiles of galaxy clusters, both without Dark Matter. We test the universality of these parameters using the temperature anisotropies due to the thermal Sunyaev–Zeldovich effect. In our model the intra-cluster gas is in hydrostatic equilibrium within the modified gravitational potential well and it is described by a polytropic equation of state. We predict the thermal Sunyaev–Zeldovich temperature anisotropies produced by Coma cluster, and we compare them with those obtained using the Planck 2013 Nominal maps. In our analysis, we find α and the scale length, respectively, to be consistent and to depart from their universal values. Our analysis points out that the assumption of the universality of the Yukawa-correction to the gravitational potential is ruled out at more than 3.5σ at galaxy clusters scale, while demonstrating that such a theory of gravity is capable to fit the cluster profile if the scale dependence of the gravitational potential is restored.
Highlights
Scalar-Tensor-Vector Gravity theory (STVG), known as MOdified Gravity (MOG), adds scalar, tensor and massive vector fields to the standard Hilbert-Einstein action [1, 2]
Since the physical state of the gas in a galaxy cluster is determined by its formation and evolution [56], our results could be interpreted as an indication that MOG could be able to explain the emergence of the large scale structure, as well as the concordance model, if the theoretical parameter of the gravitational potential are free to vary
We proposed an alternative test to probe the assumption of the universality of MOG weak field approximation [6, 18]
Summary
Scalar-Tensor-Vector Gravity theory (STVG), known as MOdified Gravity (MOG), adds scalar, tensor and massive vector fields to the standard Hilbert-Einstein action [1, 2]. Despite its successes at galactic scale, it is not clear if the assumption of the universality of those parameters holds at the scale of galaxy clusters. In general these parameters depend on the mass of the source of the gravitational potential and, they should depend on the scale length of the selfgravitating system as their analogue in f (R) gravity [4]. The universal parameters seem to be able to predict the dynamical mass of galaxy clusters [14, 15]
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