Title: Resolved CO observations of lensed dusty star-forming galaxies out to z<6

Abstract:
We present kiloparsec-scale low-J CO emission maps obtained with ATCA of a sample of 
gravitationally lensed dusty star forming galaxies discovered with the South Pole Telescope 
(SPT) millimeter survey of the southern sky. For some of these sources, we show the striking 
difference in spatial distribution between the source-plane CO maps and the cold dust maps 
obtained with ALMA at 870um.