'Polar Ring' Galaxies Found

Published in the Monthly Notices of the Royal Astronomical Society

WALLABY pilot survey: the potential polar ring galaxies NGC 4632 and NGC 6156

Paper Abstract:

We report on the discovery of two potential polar ring galaxies (PRGs) in the WALLABY Pilot Data Release 1 (PDR1). These untargeted detections, cross-matched to NGC 4632 and NGC 6156, are some of the first galaxies where the H i observations show two distinct components. We used the iDaVIE virtual reality software to separate the anomalous gas from the galactic gas and found that the anomalous gas comprises ∼50 per cent of the total H i content of both systems. We have generated plausible 3D kinematic models for each galaxy, assuming that the rings are circular and inclined at 90° to the galaxy bodies. These models show that the data are consistent with PRGs but do not definitively prove that the galaxies are PRGs. By projecting these models at different combinations of main disc inclinations, ring orientations, and angular resolutions in mock data cubes, we have further investigated the detectability of similar PRGs in WALLABY. Assuming that these galaxies are indeed PRGs, the detectability fraction, combined with the size distribution of WALLABY PDR1 galaxies, implies an incidence rate of ∼1–3 per cent. If this rate holds true, the WALLABY survey will detect hundreds of new polar ring galaxies.

Dr. Deg works with Prof. Kristine Spekkens in the physics department at Queen's University.

Polar ring galaxies are some of the most spectacular looking galaxies that we can see. Beyond just being beautiful, they provide important clues about the formation and growth of galaxies over time.  - Dr. Deg (source The Conversation)

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