A Taxonomy for the Configurations of Quadruply Lensed Quasars

TL;DR

This paper introduces a simple, coarse classification scheme for quadruply lensed quasars based on their image configuration features, aiming to aid novice understanding and testing.

Contribution

It proposes a new, easy-to-use taxonomy with only six classes focusing on shape features, simplifying the complex classification of quadruply lensed quasars.

Findings

Scheme tested on 12 quasar systems

Focuses on shape and circularity features

Provides a foundation for further refinement

Abstract

A simple, novice-friendly scheme for classifying the image configurations of quadruply lensed quasars is proposed. With only six classes, it is intentionally coarse-grained. It focuses on the kitelikeness and circularity of these configurations, or the absence thereof. Other features are deliberately ignored, their importance to professional astronomers notwithstanding. Readers are invited to test drive the scheme on a sample of 12 quadruply lensed quasar systems. The theoretical underpinnings of the scheme are described in a technical appendix.