Searching for Non-Circular Flows Linked to Bars in MaNGA Galaxies with the Radon Transform

Bars are a common linear structure of stars found at the center of about half of all spiral galaxies. They can cross large fractions of the galaxy disc, and affect not only the spiral arms, but also the motion of stars and gases within the host galaxy. Bar-driven gas inflows have been credited with feeding nuclear starbursts and/or providing fuel for active galactic nuclei. Previous studies (Stark et al. 2018) have examined the possible correlations between the existence of bars in galaxies and distortions in their velocity field using a sample of galaxies with velocity maps from the SDSS-IV MaNGA survey. We continue to investigate this correlation with a galaxy sample with both MaNGA data and Galaxy Zoo morphologies. Our sample consists of galaxies that are face-on and spiral, so would have visible bars if present. We employ the radon transform calculation tools that were developed in Stark et al. (2018) to produce the galaxies’ re-scaled Absolute Bounded Radon transform map, from which we derive their Radon profiles and uncertainty. This information describes how symmetric velocity fields are and allows us to detect noncircular motions, such as those caused by bars. We make use of a crowd-sourcing project in Zooniverse to classify the shape of stellar and gas profiles into a variety of common categories. These data are allowing us to quantify the relation between bar strength as measured in images and the impact the bar flows have on the asymmetry of observed velocity fields. Our successful classifications of 416 subjects have yielded statistics showing that more than half of the gas velocity fields have a specific type of distortion, which is likely associated with bar flows, while the stellar velocity fields, though distortion is still largely present, are more evenly distributed amongst the categories.