Measurement of fast bars in a sample of early-type barred galaxies

We present surface photometry and stellar kinematics of a sample of 5 SB0 galaxies: ESO 139-G009, IC 874, NGC 1308, NGC 1440 and NGC 3412. We measured their bar pattern speed using the Tremaine-Weinberg method, and derived the ratio, R, of the corotation radius to the length of the bar semi-major axis. For all the galaxies, R is consistent with being in the range from 1.0 and 1.4, i.e. that they host fast bars. This represents the largest sample of galaxies for which R has been measured this way. Taking into account the measured distribution of R and our measurement uncertainties, we argue that this is probably the true distribution of R. If this is the case, then the Tremaine-Weinberg method finds a distribution of R which is in agreement with that obtained by hydrodynamical simulations. We compared this result with recent high-resolution N-body simulations of bars in cosmologically-motivated dark matter halos,and conclude that these bars are not located inside centrally concentrated dark matter halos.