scholarly journals Modified Newtonian Dynamics Mass-to-Light Ratios for Galaxy Groups

2002 ◽  
Vol 577 (2) ◽  
pp. L75-L77 ◽  
Author(s):  
Mordehai Milgrom
Keyword(s):  
Galaxy Groups ◽  
Modified Newtonian Dynamics ◽  
Newtonian Dynamics

scholarly journals A historical perspective on modified Newtonian dynamics

2015 ◽  
Vol 93 (2) ◽  
pp. 126-138 ◽  
Author(s):  
R.H. Sanders
Keyword(s):  
Recent Progress ◽  
Cold Dark Matter ◽  
Theoretical Underpinning ◽  
Galaxy Groups ◽  
Modified Newtonian Dynamics ◽  
Newtonian Dynamics ◽  
Nonrelativistic Theory ◽  
Empirical Level ◽  
Multifield Theories ◽  
Theories Of Gravity

I review the history and development of modified Newtonian dynamics (MOND) beginning with the phenomenological basis as it existed in the early 1980s. I consider Milgrom’s papers of 1983 introducing the idea and its consequences for galaxies and galaxy groups, as well as the initial reactions, both negative and positive. The early criticisms were primarily on matters of principle, such as the absence of conservation laws and perceived cosmological problems; an important step in addressing these issues was the development of the Lagrangian-based nonrelativistic theory of Bekenstein and Milgrom. This theory led to the development of a tentative relativistic theory that formed the basis for later multifield theories of gravity. On an empirical level the predictive success of the idea with respect to the phenomenology of galaxies presents considerable challenges for cold dark matter. For MOND the essential challenge remains the absence of a generally accepted theoretical underpinning of the idea and, thus, cosmological predictions. I briefly review recent progress in this direction. Finally I discuss the role and sociology of unconventional ideas in astronomy in the presence of a strongly entrenched standard paradigm.

scholarly journals Newtonian Fractional-dimension Gravity and Rotationally Supported Galaxies

2021 ◽  
Author(s):  
Gabriele U Varieschi
Keyword(s):  
Fractional Dimension ◽  
Newtonian Gravity ◽  
Axially Symmetric ◽  
Local Dimension ◽  
Radial Acceleration ◽  
Modified Newtonian Dynamics ◽  
Newtonian Dynamics ◽  
The Subject ◽  
Symmetric Structures ◽  
Natural Scale

Abstract We continue our analysis of Newtonian Fractional-Dimension Gravity, an extension of the standard laws of Newtonian gravity to lower dimensional spaces including those with fractional (i.e., non-integer) dimension. We apply our model to three rotationally supported galaxies: NGC 7814 (Bulge-Dominated Spiral), NGC 6503 (Disk-Dominated Spiral), and NGC 3741 (Gas-Dominated Dwarf). As was done in the general cases of spherically-symmetric and axially-symmetric structures, which were studied in previous work on the subject, we examine a possible connection between our model and Modified Newtonian Dynamics, a leading alternative gravity model which explains the observed properties of these galaxies without requiring the Dark Matter hypothesis. In our model, the MOND acceleration constant a0 ≃ 1.2 × 10−10m s−2 can be related to a natural scale length l0, namely $a_{0} \approx GM/l_{0}^{2}$ for a galaxy of mass M. Also, the empirical Radial Acceleration Relation, connecting the observed radial acceleration gobs with the baryonic one gbar, can be explained in terms of a variable local dimension D. As an example of this methodology, we provide detailed rotation curve fits for the three galaxies mentioned above.

scholarly journals Loss of Mass and Stability of Galaxies in Modified Newtonian Dynamics

2007 ◽  
Vol 665 (2) ◽  
pp. L101-L104 ◽  
Author(s):  
Xufen Wu ◽  
HongSheng Zhao ◽  
Benoit Famaey ◽  
G. Gentile ◽  
O. Tiret ◽  
...  
Keyword(s):  
Modified Newtonian Dynamics ◽  
Newtonian Dynamics ◽  
Loss Of Mass

scholarly journals Phase Transition in Modified Newtonian Dynamics (MONDian) Self-Gravitating Systems

Entropy ◽  
2021 ◽  
Vol 23 (9) ◽  
pp. 1158
Author(s):  
Mohammad Hossein Zhoolideh Zhoolideh Haghighi ◽  
Sohrab Rahvar ◽  
Mohammad Reza Rahimi Rahimi Tabar
Keyword(s):  
Phase Transition ◽  
Binary Systems ◽  
Dimensional Space ◽  
Gravitational Interaction ◽  
Three Dimensional ◽  
Physical Parameters ◽  
Canonical Systems ◽  
Modified Newtonian Dynamics ◽  
Newtonian Dynamics ◽  
Gravitating Systems

We study the statistical mechanics of binary systems under the gravitational interaction of the Modified Newtonian Dynamics (MOND) in three-dimensional space. Considering the binary systems in the microcanonical and canonical ensembles, we show that in the microcanonical systems, unlike the Newtonian gravity, there is a sharp phase transition, with a high-temperature homogeneous phase and a low-temperature clumped binary one. Defining an order parameter in the canonical systems, we find a smoother phase transition and identify the corresponding critical temperature in terms of the physical parameters of the binary system.

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