UGC 7069: The largest ring galaxy

TL;DR

This study characterizes UGC 7069 as the largest known ring galaxy, combining multiwavelength observations and simulations to explore its structure, starburst activity, and formation through galaxy collisions.

Contribution

It provides the first comprehensive multiwavelength analysis and N-body simulations explaining the formation of this exceptionally large and warped ring galaxy.

Findings

UGC 7069 has a diameter of ~115 kpc, making it the largest known ring galaxy.

The galaxy exhibits a double-peaked nucleus and signs of starburst activity.

Simulations suggest galaxy collisions with large inclination angles produce such large, warped rings.

Abstract

We find that UGC 7069 is the largest ring galaxy known to date. In this Letter, we present a multiwavelength study of this galaxy (combining radio, 2MASS, optical and ultraviolet data). The ring of UGC 7069, whose diameter measures ~115 kpc, is also warped at its edges. The nucleus appears double-peaked and hosts a possible LINER. The ultraviolet data indicate a strong blue colour and suggest that UGC 7069 is a starburst galaxy. We also present N-body simulation results, which indicate that galaxy collisions can produce such huge rings. Large inclination angles between the target and the intruder galaxy may account for the formation of warped rings. Multiwavelength observations are highly essential to constrain our simulation results, which will address the formation and evolution of such a rare galaxy.