Non-circular motion evidence in the circumnuclear region of M100 (NGC 4321) Castillo-Morales, A. Jiménez Vicente, Jorge Mediavilla, E. Battaner López, Eduardo Galaxies NGC 4321 Kinematics and dynamics We analyse new integral field spectroscopy of the inner region (central 2.5 kpc) of the spiral galaxy NGC 4321 to study the peculiar kinematics of this region. Fourier analysis of the velocity residuals obtained by subtracting an axisymmetric rotation model from the Hα velocity field, indicates that the distortions are {\em global} features generated by an m=2 perturbation of the gravitational potential which can be explained by the nuclear bar. This bar has been previously observed in the near-infrared but not in the optical continuum dominated by star formation. We detect the optical counterpart of this bar in the 2D distribution of the old stellar population (inferred from the equivalent width map of the stellar absorption lines). We apply the Tremaine--Weinberg method to the stellar velocity field to calculate the pattern speed of the inner bar, obtaining a value of Ωb=160±70kms−1kpc−1. This value is considerably la rger than the one obtained when a simple bar model is considered. However the uncertainties in the pattern speed determination prevent us to give support to alternative scenarios. 2013-11-06T08:52:46Z 2013-11-06T08:52:46Z 2007 info:eu-repo/semantics/article Castillo-Morales, A.; et al. Non-circular motion evidence in the circumnuclear region of M100 (NGC 4321). Monthly Notices of the Royal Astronomical Society, 380(2): 489-498 (2007). [http://hdl.handle.net/10481/29035] 0035-8711 1365-2966 doi: 10.1111/j.1365-2966.2007.12104.x arXiv:0706.1945v1 http://hdl.handle.net/10481/29035 eng http://creativecommons.org/licenses/by-nc-nd/3.0/ info:eu-repo/semantics/openAccess Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License Oxford University Press (OUP); Royal Astronomical Society