Cold streams in early massive hot haloes as the main mode of galaxy formation

Understand

The 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 such events, showing gas-rich, clumpy, extended rotating disks not dominated by spheroids (Genzel et al.
• 2006, 2008).
• Cosmological simulations and clustering theory are used to explore how these galaxies acquired their gas.