ALMA CO(2–1) peak-intensity maps of the six QSO2s. The color bars indicate the scales of the flux density in mJy. The horizontal black lines indicate the physical scales for each galaxy, and the beam sizes are shown in the bottom left corner of each panel as red ellipses. The CO(2–1) distribution presents a variety of morphologies, such as spiral arms, double peaks, and merger signatures. East is to the left, and north is up.