Near-infrared observations of isophotal twists in barred spiral galaxies

We present observations in JHK passbands for 12 barred galaxies and in BI passbands for 9 galaxies in order to study isophotal twists in early- and late-type barred spirals. We also summarize previous observations and examine high-resolution atlas images to compile data on twists as a function of Hubble type. Twists have been detected only in early-type spirals. This result is consistent with the hypothesis that only early-type bars have inner Lindblad resonances and that twists are associated with ILRs. The transition occurs around type SBbc and parallels the transition from bars with relatively flat intensity profiles to bars with exponential profiles in later types. © 1996 American Astronomical Society.