CO isotopologs as observed with CARMA toward NGC 1333/IRAS 4C. ¹³CO shows a broader profile, and a significant part of the emission has possibly been resolved out by the interferometer, while C¹⁸O shows only narrow emission. The vertical line at +8 km s^-1 is the velocity of the C¹⁸O peak. The plotted flux offset between the lines has been chosen to facilitate comparison. ¹²CO is not shown because it is heavily affected by absorption, which makes using it very difficult.