As an effective means to promote progress in the main areas of Astronomy, the scientific work of the IAU is structured through its Divisions, Commissions, Working Groups and Program Groups (or equivalent).
Large galaxy cluster Abell 2218 showing effects of gravitational lensing
Credit:
ESA/NASA, J.-P. Kneib (Observ. Midi-Pyrénées) and R. Ellis (Caltech)
