scholarly journals Observational scalings testing modified gravity

2022 ◽  
Vol 21 (12) ◽  
pp. 309
Author(s):  
Armine Amekhyan ◽  
Seda Sargsyan ◽  
Arman Stepanian
Keyword(s):  
Cosmological Constant ◽  
Modified Gravity ◽  
Spiral Galaxies ◽  
Scaling Relations ◽  
Nearby Galaxy ◽  
Radiated Power ◽  
Cosmological Observations ◽  
Upper Limits ◽  
The Common ◽  
Fisher Relation

Abstract We consider different observational effects to test a modified gravity approach involving the cosmological constant in the common description of dark matter and dark energy.We obtain upper limits for the cosmological constant by studying the scaling relations for 12 nearby galaxy clusters, the radiated power from gravitational waves and the Tully-Fisher relation for super spiral galaxies. Our estimations reveal that, for all these cases, the upper limits for Λ are consistent with its actual value predicted by cosmological observations.

scholarly journals Rotation curves and scaling relations of extremely massive spiral galaxies

2021 ◽  
Author(s):  
Enrico M Di Teodoro ◽  
Lorenzo Posti ◽  
Patrick M Ogle ◽  
S Michael Fall ◽  
Thomas Jarrett
Keyword(s):  
Spiral Galaxies ◽  
High Mass ◽  
Scaling Relations ◽  
Rotation Curves ◽  
Kinematic Models ◽  
Optical Discs ◽  
Fisher Relation ◽  
Stellar Masses ◽  
Baryonic Mass ◽  
Optical Radius

Abstract We study the kinematics and scaling relations of a sample of 43 giant spiral galaxies that have stellar masses exceeding 1011 M⊙ and optical discs up to 80 kpc in radius. We use a hybrid 3D-1D approach to fit 3D kinematic models to long-slit observations of the Hα-$\rm{[N\, \small {II}]}$ emission lines and we obtain robust rotation curves of these massive systems. We find that all galaxies in our sample seem to reach a flat part of the rotation curve within the outermost optical radius. We use the derived kinematics to study the high-mass end of the two most important scaling relations for spiral galaxies: the stellar/baryonic mass Tully-Fisher relation and the Fall (mass-angular momentum) relation. All galaxies in our sample, with the possible exception of the two fastest rotators, lie comfortably on both these scaling relations determined at lower masses, without any evident break or bend at the high-mass regime. When we combine our high-mass sample with lower-mass data from the Spitzer Photometry & Accurate Rotation Curves catalog, we find a slope of α = 4.25 ± 0.19 for the stellar Tully-Fisher relation and a slope of γ = 0.64 ± 0.11 for the Fall relation. Our results indicate that most, if not all, of these rare, giant spiral galaxies are scaled up versions of less massive discs and that spiral galaxies are a self-similar population of objects up to the very high-mass end.

Cosmological constant Λ in f(R,T) modified gravity

2016 ◽  
Vol 13 (05) ◽  
pp. 1650058 ◽  
Author(s):  
Gyan Prakash Singh ◽  
Binaya Kumar Bishi ◽  
Pradyumn Kumar Sahoo
Keyword(s):  
Cosmological Model ◽  
Cosmological Constant ◽  
Modified Gravity ◽  
Bianchi Type ◽  
Field Equations ◽  
Type Iii ◽  
Expansion Scalar ◽  
Modified Theory Of Gravity ◽  
Shear Scalar ◽  
Modified Theory

In this paper, we have studied the Bianchi type-III cosmological model in the presence of cosmological constant in the context of [Formula: see text] modified theory of gravity. Here, we have discussed two classes of [Formula: see text] gravity, i.e. [Formula: see text] and [Formula: see text]. In both classes, the modified field equations are solved by the relation expansion scalar [Formula: see text] that is proportional to shear scalar [Formula: see text] which gives [Formula: see text], where [Formula: see text] and [Formula: see text] are metric potentials. Also we have discussed some physical and kinematical properties of the models.

scholarly journals Black Hole Mass Scaling Relations for Spiral Galaxies. II. M BH–M *,tot and M BH–M *,disk

2018 ◽  
Vol 869 (2) ◽  
pp. 113 ◽  
Author(s):  
Benjamin L. Davis ◽  
Alister W. Graham ◽  
Ewan Cameron
Keyword(s):  
Black Hole ◽  
Spiral Galaxies ◽  
Scaling Relations ◽  
Black Hole Mass ◽  
Mass Scaling

scholarly journals Black Hole Mass Scaling Relations for Spiral Galaxies. I. M BH–M *,sph

2019 ◽  
Vol 873 (1) ◽  
pp. 85 ◽  
Author(s):  
Benjamin L. Davis ◽  
Alister W. Graham ◽  
Ewan Cameron
Keyword(s):  
Black Hole ◽  
Spiral Galaxies ◽  
Scaling Relations ◽  
Black Hole Mass ◽  
Mass Scaling

scholarly journals Testing modified gravity models with recent cosmological observations

2012 ◽  
Vol 55 (12) ◽  
pp. 2244-2258 ◽  
Author(s):  
WenShuai Zhang ◽  
Cheng Cheng ◽  
QingGuo Huang ◽  
Miao Li ◽  
Song Li ◽  
...  
Keyword(s):  
Modified Gravity ◽  
Gravity Models ◽  
Cosmological Observations ◽  
Modified Gravity Models

scholarly journals Dynamical Chern–Simons modified gravity, Gödel Universe and variable cosmological constant

2010 ◽  
Vol 693 (4) ◽  
pp. 494-497 ◽  
Author(s):  
C. Furtado ◽  
J.R. Nascimento ◽  
A.Yu. Petrov ◽  
A.F. Santos
Keyword(s):  
Cosmological Constant ◽  
Modified Gravity ◽  
Variable Cosmological Constant ◽  
Chern Simons ◽  
Gödel Universe

The mass-to-light ratios of low surface brightness spiral galaxies: Clues from the Tully-Fisher relation

1995 ◽  
Vol 438 ◽  
pp. 72 ◽  
Author(s):  
D. Sprayberry ◽  
G. M. Bernstein ◽  
C. D. Impey ◽  
G. D. Bothun
Keyword(s):  
Surface Brightness ◽  
Spiral Galaxies ◽  
Low Surface Brightness ◽  
Fisher Relation

scholarly journals Asymptotic kinematics of globular clusters: The emergence of a Tully–Fisher relation

2019 ◽  
Vol 491 (1) ◽  
pp. 272-280
Author(s):  
X Hernandez ◽  
A J Lara-D I
Keyword(s):  
Modified Gravity ◽  
Globular Clusters ◽  
Velocity Dispersion ◽  
Initial Conditions ◽  
Gaussian Component ◽  
Gravitational Acceleration ◽  
Large Radius ◽  
Homogeneous Sample ◽  
Fisher Relation ◽  
Stellar Masses

ABSTRACT Using a recent homogeneous sample of 40 high-quality velocity dispersion profiles for Galactic globular clusters, we study the regime of low gravitational acceleration relevant to the outskirts of these systems. We find that a simple empirical profile having a central Gaussian component and a constant large-radius asymptote, σ∞, accurately describes the variety of observed velocity dispersion profiles. We use published population synthesis models, carefully tailored to each individual cluster, to estimate mass-to-light ratios from which total stellar masses, M, are inferred. We obtain a clear scaling, reminiscent of the galactic Tully–Fisher relation of $\sigma _{\infty }[\, \mathrm{km \, s}^{-1}]= 0.084^{+0.075}_{-0.040} (\mathrm{{\it M}/M}_{\odot })^{0.3 \pm 0.051}$, which is interesting to compare to the deep modified Newtonian dynamics (MOND) limit of $\sigma _{\infty } [\mathrm{km \, s}^{-1}]=0.2(\mathrm{{\it M}/M}_{\odot })^{0.25}$. Under a Newtonian interpretation, our results constitute a further restriction on models where initial conditions are crafted to yield the outer flattening observed today. Within a modified gravity scheme, because the globular clusters studied are not isolated objects in the deep MOND regime, the results obtained point towards a modified gravity where the external field effect of MOND does not appear, or is significantly suppressed.

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