Channel maps of the ¹²CO J = 2−1 line emission toward M 2 − 9 (in contours) superimposed on the optical image obtained with the Hubble Space Telescope (in color scale; Balick et al. 1997). The center is given by the position of compact continuum emission, here subtracted, at the J2000 coordinates RA 17:05:37.958, Dec  −10:08:32.48. The LSR velocities are specified in the top-left corner of each panel. Contours are shown from 4σ with a spacing of 5σ (where the root-mean-square noise is 7.9 mJy beam^-1) in solid line, and at  −4σ in dashed lines. The synthesized beam is 086  ×  040 at PA = 15° and is drawn in the bottom-right corner of the last panel.