Weak gravitational lensing in fourth order gravity

Stabile, A.; Stabile, An.

doi:10.1103/physrevd.85.044014

Cited by 24 publications

(24 citation statements)

References 62 publications

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“…On the other hand, considering that alternative gravities usually contain further degrees of freedom with respect to general relativity, a more accurate treatment has to be adopted for the lensing problem. As shown in Stabile & Stabile (2012), differences emerge as soon as as the Newtonian and the post-Newtonian formalisms are fully considered assuming also the perturbation theory of more gravitational degrees of freedom. In this perspective, differences between alternative gravity and dark matter pictures could emerge giving the signature for the final theory.…”

Section: Conclusion and Discussionmentioning

confidence: 99%

Unifying static analysis of gravitational structures with a scale-dependent scalar field gravity as an alternative to dark matter

Salzano

Mota

Capozziello

et al. 2014

A&A

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Aims. We investigated the gravitational effects of a scalar field within scalar-tensor gravity as an alternative to dark matter. Motivated by chameleon, symmetron, and f (R)-gravity models, we studied a phenomenological scenario where the scalar field has both a mass (i.e. interaction length) and a coupling constant to the ordinary matter that scale with the local properties of the considered astrophysical system. Methods. We analysed the feasibility of this scenario using the modified gravitational potential obtained in its context and applied it to the galactic and hot gas/stellar dynamics in galaxy clusters and elliptical/spiral galaxies respectively. This is intended to be a first step in assessing the viability of this new approach in the context of "alternative gravity" models. Results. The main results are 1. the velocity dispersion of elliptical galaxies can be fitted remarkably well by the suggested scalar field, with model significance similar to a classical Navarro-Frenk-White dark halo profile; 2. the analysis of the stellar dynamics and the gas equilibrium in elliptical galaxies has shown that the scalar field can couple with ordinary matter with different strengths (different coupling constants), producing and/or depending on the different clustering state of matter components; 3. elliptical and spiral galaxies, combined with clusters of galaxies, show evident correlations among theory parameters, which suggest both the general validity of our results on all scales and a way toward a possible unification of the theory for all types of the gravitational systems we considered. All these results demonstrate that the proposed scalar field scenario can work fairly well as an alternative to dark matter.

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Section: Conclusion and Discussionmentioning

confidence: 99%

Unifying static analysis of gravitational structures with a scale-dependent scalar field gravity as an alternative to dark matter

Salzano

Mota

Capozziello

et al. 2014

A&A

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“…With this situation in mind, it is urgent to find out some experimentum crucis or some test bed capable of discriminating among concurring gravitational theories (Capozziello S. Capozziello, A. Stabile et al 2010a, 2015bStabile and Scelza 2011;Stabile and Stabile 2012), that, in any case, should reproduce the wellfounded theoretical and experimental results of General Relativity. At astrophysical level, discriminations could come from anomalous stellar systems whose structures and parameters do not find room in the constraints and limits imposed by General Relativity.…”

Section: Introductionmentioning

confidence: 97%

Gravitational waves in fourth order gravity

Capozziello

Stabile

2015

Astrophys Space Sci

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In the post-Minkowskian limit approximation, we study gravitational wave solutions for general fourthorder theories of gravity. Specifically, we consider a Lagrangian with a generic function of curvature invariants f (R, R αβ R αβ , R αβγ δ R αβγ δ ). It is well known that when dealing with General Relativity such an approach provides massless spin-two waves as propagating degree of freedom of the gravitational field while this theory implies other additional propagating modes in the gravity spectra. We show that, in general, fourth order gravity, besides the standard massless graviton is characterized by two further massive modes with a finite-distance interaction. We find out the most general gravitational wave solutions in terms of Green functions in vacuum and in presence of matter sources. If an electromagnetic source is chosen, only the modes induced by R αβ R αβ are present, otherwise, for any f (R) gravity model, we have the complete analogy with tensor modes of General Relativity. Polarizations and helicity states are classified in the hypothesis of plane wave. B S. Capozziello capozziello@na.infn.it A. Stabile

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“…The weak-field limit has to be tested against realistic self-gravitating systems. Galactic rotation curves, stellar systems and gravitational lensing appear natural candidates as test-bed experiments [27][28][29][30][31][32] (see also [33][34][35]). In this perspective, corrections to GR were already considered by several authors [22,.…”

Section: Introductionmentioning

confidence: 99%

Photon frequency shift in curvature-based Extended Theories of Gravity

2021

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We study the frequency shift of photons generated by rotating gravitational sources in the framework of curvature-based Extended Theories of Gravity. The discussion is developed considering the weak-field approximation. Following a perturbative approach, we analyze the process of exchanging photons between Earth and a given satellite, and we find a general relation to constrain the free parameters of gravitational theories. Finally, we suggest the Moon as a possible laboratory to test theories of gravity by future experiments which can be, in principle, based also on other Solar System bodies.

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Weak gravitational lensing in fourth order gravity

Cited by 24 publications

References 62 publications

Unifying static analysis of gravitational structures with a scale-dependent scalar field gravity as an alternative to dark matter

Unifying static analysis of gravitational structures with a scale-dependent scalar field gravity as an alternative to dark matter

Gravitational waves in fourth order gravity

Photon frequency shift in curvature-based Extended Theories of Gravity

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