2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/9166The dynamics of a barred galaxy depends on the pattern speed of its bar. The only direct method for measuring the pattern speed of a bar is the Tremaine-Weinberg technique. This method relies on the analysis of the distribution and dynamics of the stellar component. It is best suited to gas-poor galaxies and therefore it has been restricted to early-type barred galaxies. On the other hand, a variety of indirect methods, which are based on the analysis of the distribution and dynamics of the gaseous component, has been used to measure the bar pattern speed in late-type barred galaxies. The complete sample of galaxies for which the bar pattern speed has been directly measured with the Tremaine-Weinberg method is given. Nearly all the measured bars are as rapidly rotating as they can be. By comparing this result with recent high-resolution N-body simulations of bars in cosmologically-motivated dark matter halos, it is possible to conclude that these bars are not located inside centrally-concentrated halos.5 pages. Proceedings of "Baryons in Dark Matter Halos". Novigrad, Croatia, 5-9 Oct 2004. Editors: R. Dettmar, U. Klein, P. Salucci. Published by SISSAAstrophysicstext