Exactly solved model of a one dimensional self gravitating system

Fuente: arXiv
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Main Author: Nityananda, Rajaram
Format: Preprint
Published: 2026
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author Nityananda, Rajaram
author_facet Nityananda, Rajaram
contents A model one-dimensional self consistent steady state collisionless self-gravitating system in which all the particles have the same energy is presented. This has the remarkable property that the position and velocity of the particles orbiting in their own self consistent potential are given exactly, in terms of time, by the truncations of sine and cosine functions to the first two terms in their respective Taylor series. The potential and density also have simple analytic expressions in terms of time as parameter. It is not being claimed that this system has any direct astronomical application. However, it does motivate a conjecture about the behaviour of the density, potential, and orbits near caustics in simulations of cold collisionless dark matter. It is a rather surprising result which might interest practitioners of stellar dynamics and serve as an elementary example in teaching the subject.
format Preprint
id arxiv_https___arxiv_org_abs_2601_02423
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Exactly solved model of a one dimensional self gravitating system
Nityananda, Rajaram
Astrophysics of Galaxies
Exactly Solvable and Integrable Systems
A model one-dimensional self consistent steady state collisionless self-gravitating system in which all the particles have the same energy is presented. This has the remarkable property that the position and velocity of the particles orbiting in their own self consistent potential are given exactly, in terms of time, by the truncations of sine and cosine functions to the first two terms in their respective Taylor series. The potential and density also have simple analytic expressions in terms of time as parameter. It is not being claimed that this system has any direct astronomical application. However, it does motivate a conjecture about the behaviour of the density, potential, and orbits near caustics in simulations of cold collisionless dark matter. It is a rather surprising result which might interest practitioners of stellar dynamics and serve as an elementary example in teaching the subject.
title Exactly solved model of a one dimensional self gravitating system
topic Astrophysics of Galaxies
Exactly Solvable and Integrable Systems
url https://arxiv.org/abs/2601.02423