The first galaxies: assembly of disks and prospects for direct detection

Authors: A. Pawlik, M. Milosavljevic and V. Bromm
Link to the paper: arXiv:1011.0438

The authors study the formation of a galaxy embedded in a 10⁹ solar masses halo at redshift z=10. Galaxies of this mass should be possible to observe with the James Webb Space Telescope (JWST).

The authors do not include star formation and feedback, but concentrate on the formation history of the galaxy in the presence of primordial and molecular cooling. The first result is that the galaxy for a gas disk with and without the inclusion of molecular cooling. Indeed, molecular cooling seems to act only on the thickness and fragmentation of the disk, but not on its assembly and gas content. This is one of the first simulations showing that such a halo can host a disk.

The second result is that a simple modeling of the star formation history of the galaxy gives estimates of its detectability with JWST. The authors predict that JWST could distinguish between normal and top-heavy IMF in the starburts case, and between starburst and continuous star formation. Their model can be rescaled to different values of parameters like, e.g., the escape fraction of photons.