Maps and radial profiles. Upper panels: CO velocity-integrated intensity maps derived for three representative targets selected from the galaxies of L_X bin 1 (NGC 7582; (a)), bin 2 (NGC 1068; (b)), and bin 3 (NGC 4388; (c)), as defined in Sect. 5.1. Contour levels have a logarithmic spacing from 2.5σ to 90% of the peak CO intensity inside the displayed field of view, which corresponds to 400 pc × 400 pc. The (green) ellipses identify the circular regions in the deprojected planes of the galaxies extending out to r ≤ 50 pc and r ≤ 200 pc. The (blue) filled ellipses in the bottom left corners represent the beam sizes of the observations. Lower panels: Normalized radial distributions of molecular gas derived out to r = 210 pc for the galaxies shown in the upper panels. The inner r ≤ 50 pc region is delimited by the dashed line. The estimated molecular gas concentration indices are displayed in panels (d)-to-(f).