# Two-body relaxation in modified Newtonian dynamics

@article{Ciotti2004TwobodyRI, title={Two-body relaxation in modified Newtonian dynamics}, author={Luca Ciotti and James Binney}, journal={Monthly Notices of the Royal Astronomical Society}, year={2004}, volume={351}, pages={285-291} }

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

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#### References

SHOWING 1-10 OF 12 REFERENCES

Does the missing mass problem signal the breakdown of Newtonian gravity

- Physics
- 1984

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 to… Expand

Modified Newtonian dynamics as an alternative to dark matter

- Physics
- 2002

▪ 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 is… Expand

A modification of the newtonian dynamics as a possible alternative to the hidden mass hypothesis

- Physics
- 1983

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 the… Expand

Dynamical friction. I. General considerations: the coefficient of dynamical friction

- Physics
- 1943

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 friction… Expand

MOND—theoretical aspects

- Physics
- 2002

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 small… Expand

Dark matter in dwarf spheroidals – II. Observations and modelling of Draco

- Physics
- 2002

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 of… Expand

DWARF GALAXIES OF THE LOCAL GROUP

- Physics
- 1998

▪ 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 dwarfs… Expand

The X-Ray Intracluster Medium

- Physics
- 1996

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 the… Expand

Dynamical evolution of globular clusters.

- Physics
- 1987

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.