by Bärbel Koribalski (CASS)

The hydroden distribution and velocity field of the merging galaxy pair NGC 4038/9 , also known as `The Antennae’. The radio data were taken with CSIRO’s Australia Telescope Compact Array; the small inset shows the HST image of the two merging galaxy disks to scale. The tidal tails – shaped like the antennae of an insect – were produced by gravitational interactions between the two gas-rich spiral galaxies, NGC 4038 and NGC 4039, which lost a large fraction of their hydrogen disks in the process. The small companion seen at the bottom right of both images is the edge-on dwarf galaxy ESO 572-G045.