Orbits of Colliding Galaxies
Abstract
A simple, semianalytic method is developed for obtaining the orbits of galaxies undergoing fast collisions in which the galaxies are represented by Plummer models. The results are found to agree fairly well with those of Nbody simulations. A simple formula for obtaining the angle of deflection is deduced. The maximum angle of deflection is 180° forV _{p}/V _{esc}(p)=1.00, about 36° forV _{p}/V _{esc}(p)=1.50, and about 18° forV _{p}/V _{esc}(p)=2.00, whereV _{p} is the velocity at closest approachp, andV _{esc}(p) is the parabolic velocity of escape atp. The angle of deflection of a pair of colliding elliptical galaxies without halos is about twice that for a pair of galaxies with halos for the same relative velocity at infinite separation.
 Publication:

Celestial Mechanics and Dynamical Astronomy
 Pub Date:
 January 1994
 DOI:
 10.1007/BF00692118
 Bibcode:
 1994CeMDA..58...65N
 Keywords:

 Astronomical Models;
 Elliptical Galaxies;
 Interacting Galaxies;
 Many Body Problem;
 Orbit Calculation;
 Stellar Systems;
 Angles (Geometry);
 Deflection;
 Simulation;
 Astrophysics;
 stellar systems: dynamics;
 galaxies: interaction;
 galaxies: orbits