Starscorotating with the bar at t = 1 Gyr shown at t =1 Gyr (initial time for the orbits integration) and at t = 2 and t = 4 Gyr in the orbits integration case and simulation. Maps are each rotated so that the bar is parallel to the x-axis. The red circle is the corotation radius at t = 1 Gyr. The orange circle is the corotation radius at t = 2 or t = 4 Gyr. Black contours are isocontours encompassing the local maxima of the effective potential with the pattern speed at t = 1 Gyr for the orbits integration panels, or at t = 2 or t = 4 Gyr for the simulation panels.