This map (which is based on observations with a ground-based observatory in Chile) was derived from Doppler shifts of a spectral emission line. These Doppler shifts tell us about orbital motion. Red regions show parts of NGC 4622 that are receding from us, while blue regions are parts approaching us (relative to the center of the galaxy), due to the galaxy's rotation. North is to the top and east is to the left. The north half of the galaxy recedes from us. The green cross marks the location of the optical center, and the field shown is 3.3 arcminutes on a side.

The regions where Doppler shifts were detected represent ionized clouds of hydrogen gas. These clouds distribute mainly along the two strong outer arms, which each wind 360 degrees or more. To see these ionized clouds on an image with the same orientation as the HST image, click on ionized cloud map.

Based on observations and analysis by R. Buta, G. B. Purcell, and James P. Scott, III.