Determination of orbital parameters of interacting galaxies using a genetic algorithm

Description of the method and application to artificial data

NORDITA, Blegdamsvej 17, 2100 Copenhagen, Denmark

Received: 31 October 1997
Accepted: 24 April 1998

Abstract

A method for determining the orbital parameters of interacting pairs of galaxies is presented and evaluated using artificial data. The method consists of a genetic algorithm which can search efficiently through the very large space of possible orbits. It is found that orbital parameters close to the actual orbital parameters of the pair can in general be found, even in the presence of fairly high levels of noise in the data. Both position and velocity data can be employed, but if no velocity data are available, the orbital parameters can be determined using position data only. The inner regions of the galaxies, which are difficult to model, can be neglected, and the orbital parameters can be determined using the remaining information.