2001ApJ...555..758W

We present the results of a WIYN integral field unit study of the kinematics of the ionized gas in NGC 4214, a nearby Magellanic spiral that is forming copious numbers of massive stars. While there is general agreement between the Hα and H I velocity fields for NGC 4214, there are several regions where we find the velocities of the ionized gas to be 50-100 km.s^–1 higher than the H I velocities at those radii. The higher velocities are associated with the diffuse ionized gas, particularly in regions of low H I column density, and not with the discrete H II regions that are typically associated with H I clouds. The mechanical energy dumped into the interstellar medium of NGC 4214 by the combined stellar winds of the massive stars is more than sufficient to account for the kinematics of the ionized gas. The dearth of radio continuum sources argues that supernovae associated with the most recent burst of star formation have yet to shape the distribution and kinematics of the ionized (or neutral) gas in this galaxy. We suggest that the detected outflows of ionized gas are the result of windblown bubbles and expanding ionization fronts accelerating as they encounter the steep density gradients from H I clouds to H I holes.