CO (2–1) emission observed with ALMA in the central region of ESO 320-G030. Panels a–c show with colors the integrated intensity (moment 0), velocity field (moment 1), and velocity dispersion (moment 2). The hatched ellipse in panel a indicates the ALMA beam. The dotted black line indicates the approximate direction of the nuclear bar (PA = 75°, see Fig. 17a), and the dashed lines are the kinematic major and minor axes (MKA and mKA). The small green contour at the center is the lowest H₂O448 contour in Fig. 4b. The yellow dotted curves indicate circles in the plane of the galaxy with radii r = 3″, 2″, 1.5″, 1″, and 0.5″. d–h) Position-velocity diagrams along the above circles. The green curves show the purely rotational velocity field fitted by Pereira-Santaella et al. (2016) to a region of 10″ in size that excludes the nuclear region, with V_rot = 250, 260, 280, 280, and 150 km s⁻¹ in panels d–h, respectively. We have here modified this velocity field in the nuclear region, including azimuthal variations of the rotational and radial velocity components of the gas, as depicted with the red dashed curves, with values for V_rot and V_rad displayed in Figs. 16a–b. The PA of the stellar bar is indicated in cyan, and the PA of the MKA and mKA are indicated with long and short vertical arrows, respectively. The clockwise direction of rotation is indicated with arrows in panels a and d. Panel f: labels “inf” and “out” indicate regions with a radial velocity component negative (inflow) and positive (outflow), respectively, colored according to the velocity shift. Contour levels in panels d–h are 4.5, 9.0, 13.5, 19, 27, 54, and 108 mJy beam⁻¹.