Central panel: FCRAO integrated intensity maps of the B211-B213 region in C¹⁸O(1−0) (gray scale and black contours) and N₂H⁺(1−0) (red contours). Left and right panels: spectra from selected positions illustrating the complex velocity structure of the emission. The blue spectra correspond to C¹⁸O(2−1) and the red spectra correspond to the isolated (F₁F = 01–12) component of N₂H⁺(1−0) (multiplied by 3) observed simultaneously with the IRAM 30 m telescope. Note the presence of 5 different C¹⁸O peaks in panel 3.