Galaxies zC-488879 at z ≃ 1.47 (left) and zC-400569 at z ≃ 2.24 (right). The HST/WFC3 image in the NIR F160W filter (gray scale) is overlaid with CO(2 − 1) emission (green contours), CO(3 − 2) emission (blue contours), and CO(4 − 3) emission (cyan contours). Contours are at (3, 6, 12, 24) σ_map with the values of 3σ_map given in Table 1. The band 4 observations have lower quality than the band 3 ones, so the different spatial extent of CO(3 − 2) and CO(4 − 3) emission in zC-400569 may be due to sensitivity rather than being physical.