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Proposing Institution

Institut für Astrophysik, ZAH, Universität Heidelberg
Project Manager

Anna Schauer
Albert-Ueberle-Str. 2
69120 Heidelberg
How, when and where the first stars formed in the Universe is a question of fundamental interest. Without stars, the Universe would consist of hydrogen and helium only, as heavier elements are bred in stars and supernovae. We would like to understand how the first stars, so-called Population III stars, and black holes formed to derive a consistent picture from the Big Bang until the present day. First star formation proceeds fundamentally different from stellar birth today, as the thermodynamic behaviour of the gas is very different. The sites of first star formation are currently out of reach of the largest telescopes, but will come closer in the next decade. Therefore, it is crucial to now run simulations that predict properties of the formation of the first stars and their birth environment. To get a consistent picture of the history of the early Universe, we need to consider non-linear effects that influence the star formation. We therefore study the influence of streaming velocities and Lyman-Werner background (LWBG) radiation on the formation of the first stars. Both are known todelay star formation and to increase the minimum halo mass necessary for Population III star formation, and we now investigate for the first time which effect is dominating. We claim to run a set of highly resolved cosmological simulations with the moving mesh code AREPO (including a network of primordial chemistry) with initially 1024^3 gas cells and dark matter particles each and a box length of 1 or 4 comoving Mpc/h. We include streaming velocities of zero, 1, 2 and 3 sigma and LWBGs of zero, 0.1 and 0.01 J21 and run all combinations thereof. With our simulations, we will be able to characterise the delay due to streaming velocities and a LWBG quantitatively and determine which of these effects is dominating.

Impressum, Conny Wendler