Rotational diagrams of CO. The base-10 logarithm of the number of emitting molecules from the upper level, , divided by the degeneracy of the level, g_up, is shown as a function of energy of the upper level in kelvins, E_up. Detections are shown as filled circles, whereas three-sigma upper limits are shown as empty circles. The empty upper triangle corresponds to the line flux calculated using a smaller area on the map than the rest of the lines. Blue lines show linear fits to the data and the corresponding rotational temperatures. Errors associated with the least-square linear fit are shown in brackets.