The origin and dynamics of high-redshift disk galaxies

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The redshift two Universe ist one of the most interesting

epochs of galaxy evolution. It is the era with the peak

of the cosmic star formation rate. Between redshift 3 and 1

the total stellar mass density in galaxies increased from

15% to 70%. It is also the time of rapid galaxy assembly and the epoch

where galaxy morphology was determined.

I will summarize recent observations of the SINS survey, a Spectroscopic

Imaging survey of z=2 galaxies in the near infrared with SINFONI.

This survey has opened a fascinating window into early galaxy evolution.

The SINS data show a diversity of galactic systems at redshift 2

with physical properties that are unparalleled in the z=0 Universe.

Gas-rich, extended, fast rotating and highly turbulent disks have been found

with star formation rates that are a factor of 10 to 100

larger than in present-day Milky-Way type galaxies. Kpc-sized, massive gas clumps dominate

the appearance of these galaxies. These giant clumps are considered to represent the progenitors of

present-day globular clusters. They could provide the seeds for supermassive black holes and they might

lead to the formation of young bulges in the centers of their galaxies.

These fascinating and puzzling observations will be confronted with theoretical ideas and numerical simulations of

gas-rich galactic disk evolution (Behrendt et al. 15, 16). I will argue that the high-redshift galaxies,

like present-day disks, are in a self-organized equilibrium state with their observed extreme

properties emerging naturally from self-regulated galactic evolution, controlled by gas inflow from the

cosmic web.