The sky field around the position of B1954+513, as in Fig. 2. In the map at lower left the grayscale represents the total integrated emission at  −1  ≤  v  ≤  2 km s^-1 and the red and blue contours show the individual distributions of red and blue-shifted components, respectively. Profiles at the peak of the red and blue-shifted emission components are shown at upper right along with the profile toward the continuum source (shaded).