Tidal tails tell tales of newborn galaxies

Talk about big-time mergers. In the infant universe, marauding galaxies devoured each other, coalescing to form bigger galaxies. These hostile takeovers spewed out truly hot commodities—gas and dust that could become the ingredients for nascent stars.

The tug of war between two galaxies (left) has created two tidal tails. Inset shows the lower tail, indicating locations of atomic hydrogen (white contour lines) and carbon monoxide (faint red circle).