Tuesday

Bars are found in around 30-70% disc dominated galaxies, they are thought to play an important role in secular evolution through enabling radial transfer of material. It is observed that redder, more massive disc galaxies are more likely to host strong bars. This hints at a role for bars, not only in growing central bulges, but also in moving disc galaxies out of the blue cloud. What is less clear is whether the link is casual: does the appearance of a bar help cease star formation in disc galaxies, or is it merely a side effect of other processes that cause this transition? I have been using HI observations to investigate some of the unusual and rare gas-rich and strongly barred systems found with Galaxy Zoo.