Molecular gas distribution of the galaxy NGC 1097. The different ellipses represent the best elliptical annulus (red, solid line) and uncertainty ellipses (black, dashed lines), indicating emission which is definitely ring material (narrower annulus: strict mask) and emission that might still be ring material (wider annulus: broad mask). The white circle in the lower left corner indicates the beam size and a scalebar is provided in the lower right. The color bar indicates the integrated intensity in terms of the brightness temperature.