Year: 2004
Type: article
Abstract: The Euclidean algorithm in algebra is applied to a class of gravitational lenses for which the lens equation consists of any set of coupled polynomial equations in the image position. In general, this algorithm allows us to reduce an apparently coupled system to a single polynomial in one variable (say x in Cartesian coordinates) without the other component (say y), which is expressed as a function of the first component. This reduction enables us to investigate the lensing properties in an algebraic manner: For instance, we can obtain an analytic expression of the caustics by computing the discriminant of the polynomial equation. To illustrate this Euclidean algorithm, we re-examine a binary gravitational lens and show that the lens equation is reduced to a single real fifth-order equation, in agreement with previous works. We apply this algorithm also to the linearlized Kerr lens and find that the lens equation is reduced to a single, real fifth-order one.
Source: Progress of Theoretical Physics
DOI: 10.1143/ptp.112.241
Authors: Hideki Asada, Taketoshi Kasai, Masumi Kasai
Institutions: Hirosaki University, Institut d'Astrophysique de Paris
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2109531320