scholarly journals Modified gravity models and the central cusp of dark matter haloes in galaxies

2014 ◽  
Vol 445 (4) ◽  
pp. 3823-3838 ◽  
Author(s):  
Davi C. Rodrigues ◽  
Paulo L. de Oliveira ◽  
Júlio C. Fabris ◽  
Gianfranco Gentile
Keyword(s):  
Dark Matter ◽  
Modified Gravity ◽  
Gravity Models ◽  
Central Cusp ◽  
Modified Gravity Models

scholarly journals Dwarf galaxies without dark matter: constraints on modified gravity

2020 ◽  
Vol 501 (1) ◽  
pp. 254-260
Author(s):  
Ali Rida Khalifeh ◽  
Raul Jimenez
Keyword(s):  
Dark Matter ◽  
Modified Gravity ◽  
Virial Theorem ◽  
Dwarf Galaxies ◽  
Strong Support ◽  
Gravity Models ◽  
Birkhoff Theorem ◽  
Astronomical Surveys ◽  
Stringent Test ◽  
Modified Gravity Models

ABSTRACT The discovery of 19 dwarf galaxies without dark matter (DM) provides, counterintuitively, strong support for the ΛCDM standard model of cosmology. Their presence is well accommodated in a scenario where the DM is in the form of cold dark particles. However, it is interesting to explore quantitatively what is needed from modified gravity models to accommodate the presence of these galaxies and what extra degree of freedom is needed in these models. To this end, we derive the dynamics at galaxy scales (Virial theorem) for a general class of modified gravity models. We distinguish between theories that satisfy the Jebsen–Birkhoff theorem, and those that do not. Our aim is to develop tests that can distinguish whether DM is part of the theory of gravity or a particle. The 19 dwarf galaxies discovered provide us with a stringent test for models of modified gravity. Our main finding is that there will always be an extra contribution to the Virial theorem coming from the modification of gravity, even if a certain galaxy shows very small, if not negligible, trace of DM, as has been reported recently. Thus, if these and more galaxies are confirmed as devoid (or negligible) of DM, while other similar galaxies have abundant DM, it seems interesting to find modifications of gravity to describe DM. Our result can be used by future astronomical surveys to put constraints on the parameters of modified gravity models at astrophysical scales where DM is described as such.

scholarly journals Clustering and redshift-space distortions in modified gravity models with massive neutrinos

2019 ◽  
Vol 488 (2) ◽  
pp. 1987-2000 ◽  
Author(s):  
Jorge Enrique García-Farieta ◽  
Federico Marulli ◽  
Alfonso Veropalumbo ◽  
Lauro Moscardini ◽  
Rigoberto A Casas-Miranda ◽  
...  
Keyword(s):  
Dark Matter ◽  
Modified Gravity ◽  
Large Scale ◽  
Cold Dark Matter ◽  
Gravity Models ◽  
Linear Growth Rate ◽  
Λcdm Model ◽  
Point Correlation ◽  
Massive Neutrinos ◽  
Modified Gravity Models

Abstract Modified gravity and massive neutrino cosmologies are two of the most interesting scenarios that have been recently explored to account for possible observational deviations from the concordance Λ cold dark matter (ΛCDM) model. In this context, we investigated the large-scale structure of the Universe by exploiting the dustgrain-pathfinder simulations that implement, simultaneously, the effects of f(R) gravity and massive neutrinos. To study the possibility of breaking the degeneracy between these two effects, we analysed the redshift-space distortions in the clustering of dark matter haloes at different redshifts. Specifically, we focused on the monopole and quadrupole of the two-point correlation function, both in real and redshift space. The deviations with respect to ΛCDM model have been quantified in terms of the linear growth rate parameter. We found that redshift-space distortions provide a powerful probe to discriminate between ΛCDM and modified gravity models, especially at high redshifts (z ≳ 1), even in the presence of massive neutrinos.

scholarly journals A generic test of modified gravity models which emulate dark matter

2007 ◽  
Vol 652 (5-6) ◽  
pp. 213-216 ◽  
Author(s):  
E.O. Kahya ◽  
R.P. Woodard
Keyword(s):  
Dark Matter ◽  
Modified Gravity ◽  
Gravity Models ◽  
Modified Gravity Models

scholarly journals Equivalence principle implications of modified gravity models

2009 ◽  
Vol 80 (10) ◽  
Author(s):  
Lam Hui ◽  
Alberto Nicolis ◽  
Christopher W. Stubbs
Keyword(s):  
Modified Gravity ◽  
Equivalence Principle ◽  
Gravity Models ◽  
Modified Gravity Models

Cosmological implications and thermodynamics of some reconstructed modified gravity models

2020 ◽  
Vol 27 ◽  
pp. 100409 ◽  
Author(s):  
Abdul Jawad ◽  
Shamaila Rani ◽  
M. Haris Hussain
Keyword(s):  
Modified Gravity ◽  
Gravity Models ◽  
Modified Gravity Models

scholarly journals Modified Gravity Models Admitting Second Order Equations of Motion

Entropy ◽  
2015 ◽  
Vol 17 (12) ◽  
pp. 6643-6662 ◽  
Author(s):  
Aimeric Colléaux ◽  
Sergio Zerbini
Keyword(s):  
Modified Gravity ◽  
Equations Of Motion ◽  
Second Order ◽  
Gravity Models ◽  
Second Order Equations ◽  
Modified Gravity Models
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