Massive galaxies in the young universe (ten billion years ago) formed stars at surprising intensities. Although this is commonly attributed to violent mergers, the properties of many of these galaxies are incompatible with mergers. This paper reports that they are 'stream-fed galaxies', growing via steady, narrow, cold gas streams. Unlike destructive mergers, the smoother flows are likely to keep the rotating disc configuration intact.
- A. Dekel
- Y. Birnboim
- E. Zinger
