The formation of massive Pop III stars in the presence of turbulence
  Population III stars forming in the infant universe at z=30 heralded the end
of the cosmic dark ages. They are presumed to be assembled in so-called
minihaloes with virial temperatures of a few thousand K where collapse is
triggered by molecular hydrogen cooling. A central question concerns their
final masses, and whether fragmentation occurs during their formation. While
studies employing Lagrangian codes suggest fragmentation via a self-gravitating
disk, recent high resolution simulations indicated that disk formation is
suppressed. Here we report the first high-resolution large-eddy simulations
performed with the Eulerian grid-based code Enzo following the evolution beyond
the formation of the first peak, to investigate the accretion of the central
massive clump and potential fragmentation. For a total of 3 halos, we see that
a disk forms around the first clump. The central clump reaches $\sim10$ solar
masses after 40 years, while subsequent accretion is expected at a rate of
$10^{-2}$ solar masses per year. In one of these halos, additional clumps form
as a result of fragmentation which proceeds at larger scales. We note that
subgrid-scale turbulence yields relevant contributions to the stability of the
protostellar disks. We conclude that the first protostar may reach masses up to
$\rm 40-100 M_{\odot}$, which are only limited by the effect of radiative
feedback.
