Suppressed or Enhanced Central Star Formation Rates in Late-type Barred Galaxies

Abstract

Bars in disk-dominated galaxies are able to drive gas inflow inside the corotation radius, thus enhancing the central star formation rate (SFR). Previous work, however, has found that disk-dominated galaxies with centrally suppressed SFRs frequently host a bar. Here we investigate possible causes for the suppression of central SFRs in such cases. We compare the physical properties of a sample of disk-dominated barred galaxies with high central SFRs (HC galaxies) with those of a sample of disk-dominated barred galaxies with low central SFRs (LC galaxies). We find that the two samples have, on average, similar H i content and bars of similar strength. But we also find that the HCs have bluer colors than the LCs, and that outside the bar region, they host stronger spiral arms than the LCs, where closed rings are more often seen. We discuss and evaluate the possible causes for the suppression of the central SFR in the LC galaxies as opposed to its enhancement in the HC galaxies.