Bar pattern speed evolution over the las 7 Gyr Pérez, Isabel Aguerri, J. A. L. Méndez-Abreu, J. Galaxies High redshift Evolution Structure Kinematics and dynamics Context. The tumbling pattern of a bar is the main parameter characterising its dynamics. From numerical simulations, its evolution since bar formation is tightly linked to the dark halo in which the bar is formed through dynamical friction and angular momentum exchange. Observational measurements of the bar pattern speed with redshift can restrict models of galaxy formation and bar evolution. Aims. We aim to determine for the first time the bar pattern speed evolution with redshift based on morphological measurements. Methods. We have selected a sample of 44 low-inclination ringed galaxies from the SDSS and COSMOS surveys covering the redshift range 0 < z < 0.8 to investigate the evolution of the bar pattern speed. We derived morphological ratios between the deprojected outer ring radius (Rring) and the bar size (Rbar). This quantity is related to the parameter ℛ = RCR/Rbar used for classifiying bars in slow and fast rotators, and allows us to investigate possible differences with redshift. Results. We obtain a similar distribution of R at all redshifts. We do not find any systematic effect that could be forcing this result. Conclusions. The results obtained here are compatible with the main bulk of the bar population (~70%) being fast-rotators and with no evolution of the pattern speed with redshift. We argue that if bars are long-lasting structures, the results presented here imply that there has not been a substantial angular momentum exchange between the bar and halo, as predicted by numerical simulations. In consequence, this might imply that the discs of these high surface-brightness galaxies are maximal. 2013-10-15T09:16:15Z 2013-10-15T09:16:15Z 2012 preprint Pérez, I.; Aguerri, J.A.L.; Méndez-Abreu, J. Bar pattern speed evolution over the las 7 Gyr. Astronomy and Astrophysics, 540: A103 (2012). [http://hdl.handle.net/10481/28431] 0004-6361 1432-0746 arXiv:1202.1929v1 http://hdl.handle.net/10481/28431 10.1051/0004-6361/201118396 eng http://creativecommons.org/licenses/by-nc-nd/3.0/ open access Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License European Southern Observatory (ESO); Springer Verlag