WiNDS: An H α Kinematics Survey of Nearby Spiral Galaxies—Vertical Perturbations in Nearby Disk-type Galaxies

Abstract

Abstract We present the Waves in Nearby Disk galaxies Survey (WiNDS) consisting of 40 nearby low-inclination disk galaxies observed through H α high-resolution Fabry–Perot interferometry. WiNDS consists of 12 new galaxy observations and 28 data archived observations obtained from different galaxy surveys. We derive two-dimensional line-of-sight velocity fields that are analyzed to identify the possible presence of vertical velocity flows in the galactic disks of these low-inclination late-type galaxies using velocity residual maps, derived from the subtraction of an axisymmetric rotation model from a rotational velocity map. Large and globally coherent flows in the line-of-sight velocity of nearly face-on galaxies can be associated with large vertical displacement of the disk with respect to its midplane. Our goal is to characterize how frequent vertical perturbations, such as those observed in the Milky Way, arise in the local universe. Our currently available data have allowed us to identify 20% of WiNDS galaxies with strong velocity perturbations that are consistent with vertically perturbed galactic disks.