A new collisional ring galaxy at z = 0.111: Auriga's Wheel

Abstract

We report the serendipitous discovery of a collision ring galaxy, identified as 2MASX J06470249+4554022, which we have dubbed "Auriga's Wheel," found in a SUPRIME-CAM frame as part of a larger Milky Way survey. This peculiar class of galaxies is the result of a near head-on collision typically between a late-type and an early-type galaxy. Subsequent Gemini Multi-object Spectrograph North long-slit spectroscopy has confirmed both the relative proximity of the components of this interacting pair and has shown that it has a redshift of 0.111. Analysis of the spectroscopy reveals that the late-type galaxy is a LINER class active galactic nucleus (AGN) while the early-type galaxy is also potentially an AGN candidate; this is very uncommon among known collision ring galaxies. Preliminary modeling of the ring finds an expansion velocity of ∼ 200kms-1 consistent with our observations, making the collision about 50 Myr old. The ring currently has a radius of about 10kpc and a bridge of stars and gas is also visible connecting the two galaxies. © 2011. The American Astronomical Society. All rights reserved.