Two-body relaxation in modified Newtonian dynamics

  title={Two-body relaxation in modified Newtonian dynamics},
  author={Luca Ciotti and James Binney},
  journal={Monthly Notices of the Royal Astronomical Society},
  • L. Ciotti, J. Binney
  • Published 1 March 2004
  • Physics
  • Monthly Notices of the Royal Astronomical Society
A naive extension to modified Newtonian dynamics (MOND) of the standard computation of the two-body relaxation time t 2b implies that t 2b is comparable to the crossing time regardless of the number N of stars in the system. This computation is questionable in view of the non-linearity of MOND's field equation. A non-standard approach to the calculation of t 2b is developed that can be extended to MOND whenever discreteness noise generates force fluctuations that are small compared to the mean… Expand
Dynamical friction in Modified Newtonian Dynamics
We have tested a previous analytical estimate of the dynamical friction time-scale in modified Newtonian dynamics (MOND) with fully non-linear N-body simulations. The simulations confirm that theExpand
Quasi-linear formulation of MOND
A new formulation of modified Newtonian dynamics (MOND) as a modified-potential theory of gravity is propounded. In effect, the theory dictates that the MOND potential φ produced by a massExpand
Radial-orbit instability in modified Newtonian dynamics
The stability of radially anisotropic spherical stellar systems in modified Newtonian dynamics (MOND) is explored by means of numerical simulations performed with the N-body code n-mody. We find thatExpand
Evolution of spiral galaxies in modified gravity II. Gas dynamics
The stability of spiral galaxies is compared in modified Newtonian Dynamics (MOND) and Newtonian dynamics with dark matter. We extend our previous simulations that involved pure stellar discs withoutExpand
Dissipationless Collapses in Modified Newtonian Dynamics
Dissipationless collapses in modified Newtonian dynamics (MOND) are studied by using a new particle-mesh N-body code based on our numerical MOND potential solver. We found that low surface densityExpand
Separable triaxial potential–density pairs in modified Newtonian dynamics
We study mass models that correspond to modified Newtonian dynamics (MOND) (triaxial) potentials for which the Hamilton–Jacobi equation separates in ellipsoidal coordinates. The problem is firstExpand
Gaseous drag on a gravitational perturber in Modified Newtonian Dynamics and the structure of the wake
We calculate the structure of a wake generated by, and the dynamical friction force on, a gravitational perturber travelling through a gaseous medium of uniform density and constant backgroundExpand
Galactic orbital motions in the dark matter, modified Newtonian dynamics and modified gravity scenarios
We simultaneously integrate in a numerical way the equations of motion of both the Magellanic Clouds (MCs) in the MOdified Newtonian Dynamics (MOND), MOdified Gravity (MOG) and cold dark matter (CDM)Expand
Roche Lobe Sizes in Deep-MOND Gravity
MOdified Newtonian Dynamics (MOND) is evolving from an empirical to a decent theory respect- ing fundamental physics after Bekenstein (2004) showed that lensing and Hubble expansion can be modeledExpand
Vertical dynamics of disc galaxies in modified Newtonian dynamics
We investigate the possibility of discriminating between modified Newtonian dynamics (MOND) and Newtonian gravity with dark matter, by studying the vertical dynamics of disc galaxies. We considerExpand


Does the missing mass problem signal the breakdown of Newtonian gravity
We consider a nonrelativistic potential theory for gravity which differs from the Newtonian theory. The theory is built on the basic assumptions of the modified dynamics, which were shown earlier toExpand
Modified Newtonian dynamics as an alternative to dark matter
▪ Abstract Modified Newtonian dynamics (MOND) is an empirically motivated modification of Newtonian gravity or inertia suggested by Milgrom as an alternative to cosmic dark matter. The basic idea isExpand
A modification of the newtonian dynamics as a possible alternative to the hidden mass hypothesis
The author considers the possibility that there is not, in fact, much hidden mass in galaxies and galaxy systems. If a certain modified version of the Newtonian dynamics is used to describe theExpand
Dynamical friction. I. General considerations: the coefficient of dynamical friction
In this paper it is shown that a star must experience dynamical friction, i.e., it must suffer from a systematic tendency to be decelerated in the direction of its motion. 'This dynamical frictionExpand
MOND—theoretical aspects
Abstract I discuss open theoretical questions pertaining to the modified dynamics (MOND)—a proposed alternative to dark matter, which posits a breakdown of Newtonian dynamics in the limit of smallExpand
Dark matter in dwarf spheroidals – II. Observations and modelling of Draco
We present stellar radial velocity data for the Draco dwarf spheroidal (dSph) galaxy obtained using the AF2/WYFFOS instrument combination on the William Herschel Telescope. Our data set consists ofExpand
▪ Abstract The Local Group dwarf galaxies offer a unique window to the detailed properties of the most common type of galaxy in the Universe. In this review, I update the census of Local Group dwarfsExpand
The X-Ray Intracluster Medium
Clusters of galaxies are the largest aggregates of matter that have decoupled from the universal expansion and have approximately evolved to a proper dynamical equilibrium configuration. While in theExpand
Dynamical evolution of globular clusters.
Abstract A brief review of pre- and post-collapse evolution of globular clusters is given. Particular attention is paid to gravothermal oscillations of cores of globular clusters.
Dynamical Evolution of Globular Clusters