DARK MATTER HALOS OF BARRED DISK GALAXIES

Abstract

We use a large volume-limited sample of disk galaxies drawn from the Sloan Digital Sky Survey Data Release 7 to study the dependence of the bar fraction on the stellar-to-halo mass ratio, making use of a group catalog, and we identify central and satellite galaxies in our sample. For the central galaxies in the sample we estimate the stellar-to-halo mass ratio (M∗/Mh) and find that the fraction of barred galaxies is a strong function of this ratio, especially for the case of strong bars. Bars are more common in galaxies with high M∗/Mh values, as expected from early theoretical works that showed that systems with massive dark matter halos are more stable against bar instabilities. We find that the change of the bar fraction with Mh and M∗ is stronger if we consider a relation with the form fbar = fbar(M∗α/Mh) with α = 1.5, and that the bar fraction is largely independent of other physical properties such as color and spin parameter when M∗3/2/Mh is fixed. With our sample of galaxies segregated into centrals and satellites, we also compare the fraction of barred galaxies in each group, finding a slightly higher bar fraction for satellites when compared with centrals at fixed stellar mass, but at fixed color this difference becomes very weak. This result, in agreement with previous studies, confirms that the bar fraction does not directly depend on the group/cluster environment, but the dependence exists through its dependence on internal morphology.