11 research outputs found
WALLABY Pilot Survey: the Potential Polar Ring Galaxies NGC~4632 and NGC~6156
We report on the discovery of two potential polar ring galaxies (PRGs) in the
WALLABY Pilot Data Release 1 (PDR1). These untargetted detections,
cross-matched to NGC 4632 and NGC 6156, are some of the first galaxies where
the Hi observations show two distinct components. We used the iDaVIE virtual
reality software to separate the anomalous gas from the galactic gas and find
that the anomalous gas comprises ~ 50% 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 degrees 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 disk inclinations, ring orientations, and
angular resolutions in mock datacubes, 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%. If this rate
holds true, the WALLABY survey will detect hundreds of new polar ring galaxies.Comment: Accepted to MNRAS -- Corrected Table