Bar Properties as a Function of Hubble Type

Abstract

AbstractPrevious optical surface photometry of barred spiral galaxies revealed that there are two distinct types of bars: large bars tend to have a nearly constant surface brightness (”flat“ bar), while smaller bars tend to have a decreasing surface brightness with a scale length similar to the disk (”exponential“ bar). Statistically, flat bars tend to occur in early Hubble types and exponential bars in later types. Studies of resonances in spirals indicate that flat bars end inside corotation, while exponential bars end between the inner Lindblad and 4:1 resonances. Near-infrared (JHK) surface photometry of bars is presented in order to compare the stellar distributions and bar potentials in flat and exponential barred galaxies. The presence of isophotal twists in some galaxies provides additional information on resonances. The grand design and fiocculent optical structures in the two types of barred galaxies will be compared and contrasted with their near-infrared light distributions.