Lecturer: Andreas Burkert , Ludwig Maximilians University, Munich
Abstract:
Disk galaxies are the fundamental building blocks of our Universe. They are the places where stars form and where the chemical elements are generated that lead to the formation of planets and to the origin of life.
However, despite their importance, the structure and origin of disk galaxies is still puzzling.
Rotational velocities indicate the existence of a surrounding and confining halo of dark matter.
The origin and nature of dark matter is still not understood. In addition, star forming galaxies, like the Milky Way, are in a suprisingly fine tuned self-organized equilibrium
state with very inefficient star formation, despite enormous amounts of cold gas that theoretically could collapse gravitationally and burst into stars on small timescales. It is due to this inefficiency of star formation that our solar system and life on Earth could form, 4.6 billion years ago.
With powerful new telescopes and instruments astronomers can now observe distant star-forming galaxies, corresponding to an early cosmic epoch, 3 Gyrs after the Big Bang. Quite unexpectedly, these young galactic disks reveal physical properties that are unparalleled in the present Universe. Star formation rates are a factor of 10 to 100 larger.
Gigantic, massive gas clumps dominate the appearance of these galaxies.
Even more interesting are their rotational properties that leave no room for a surrounding dark matter halo.
I will summarize the newest observations and the puzzles and challenges that they generate
for our understanding of cosmic galaxy formation.