Another Relativistic Generalization Of MOND Takes On Cosmology

Recently a relativistic generalization of MOND successfully addressed the cosmic background radiation signature. This one addresses dark energy phenomena. 

MOG, a similar modified gravity theory generalized relativistically takes on galactic cluster phenomena (one of MOND's weak points).

[Submitted on 4 Aug 2020]

Relativistic extensions of MOND using metric theories of gravity with curvature-matter couplings and their applications to the accelerated expansion of the Universe without dark components

E. Barrientos, T. Bernal, S. Mendoza

We discuss the advantages of using metric theories of gravity with curvature-matter couplings in order to construct a relativistic generalisation of the simplest version of Modified Newtonian Dynamics (MOND), where Tully-Fisher scalings are valid for a wide variety of astrophysical objects. We show that these proposals are valid at the weakest perturbation order for trajectories of massive and massless particles (photons). These constructions can be divided into local and non-local metric theories of gravity with curvature-matter couplings. Using the simplest two local constructions in a FLRW universe for dust, we show that there is no need for the introduction of dark matter and dark energy components into the Friedmann equation in order to account for type Ia supernovae observations of an accelerated universe at the present epoch.

Comments:	13 pages, 2 figures, 3 tables
Subjects:	General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Cite as:	arXiv:2008.01800 [gr-qc]
	(or arXiv:2008.01800v1 [gr-qc] for this version)

[Submitted on 4 Aug 2020]

Applying Modified Gravity (MOG) to the Lensing and Einstein Ring in Abell 3827

J. W. Moffat, V. T. Toth

The lensing and Einstein ring at the core of the galaxy cluster Abell 3827 are reproduced in the modified gravity theory MOG. The estimated effective lensing mass ML=(1+α)Mb=5.2×1012M⊙ within R=18.3~kpc for a baryon mass Mb=1.0×1012M⊙ within the same radius produces the observed Einstein ring angular radius θE=10″. A detailed derivation of the total lensing mass is based on modeling of the cluster configuration of galaxies, intra cluster light and X-ray emission. The MOG can fit the lensing and Einstein ring in Abell 3827 without dark matter as well as General Relativity with dark matter.

Comments:	4 pages, 1 figure. arXiv admin note: substantial text overlap with arXiv:2006.12550
Subjects:	General Relativity and Quantum Cosmology (gr-qc)
Cite as:	arXiv:2008.02137 [gr-qc]
	(or arXiv:2008.02137v1 [gr-qc] for this version)