Bar formation in simulated disc galaxies

We study the formation and evolution of barred galaxies using the EAGLE set of cosmological hydrodynamical simulations of galaxy formation. At redshift z = 0, we construct a sample of 269 central disc galaxies selected to have a narrow range of stellar mass 10.6 < log(M Gal /M ⊙ ) < 11 and classified according to the strength of the barred stellar component. These simulated galaxies shows a wide range of bar strength, pattern speed and bar length. We find that our simulated galaxies are similar to observed ones having comparable sizes and slightly lower pattern speed. We find that the bar strength anti-correlates with the galaxy star formation rate, characteristic formation time of the stellar population, half mass stellar radius, gaseous mass and degree of rotational support. We also test the Efstathiou et al. (1982) instability criterion and find a good correlation with the bar strength. We improve this criterion by measuring how are the circular velocity profiles of disc galaxies. Galaxies that will form a bar show declining circular velocity curves due to the dominant contribution of baryons in the inner regions. Conversely, galaxies that won’t form a bar show rising circular velocity profile.