Christian Arnold (Germany)
christian.arnold @ h-its.org
Cosmological simulations in modified gravity
Finding a theoretical explanation for the late time accelerated expansion of the Universe is one of the big tasks in modern cosmology. Modified gravity models can explain this expansion without a cosmological constant by modifying the laws of gravity. These changes result in gravitational forces which are different from GR in certain regions and thus would influence the formation of structures in the universe. One can therefore constrain or verify those theories performing cosmological simulations in modified gravity and comparing the properties of the simulated astrophysical objects to observations. So far, we have considered the Hu & Sawicki f(R)-gravity model in our simulations. It features the chameleon screening mechanism to restore GR in high density regions (e.g our local environment). Employing the modified gravity simulation code MG-Gadget, we analysed the properties of galaxy clusters and of the Lyman-alpha forest in f(R)-gravity. We find that galaxy cluster velocity dispersions, ICM temperatures, mass measures and the Sunyaev-Zeldovich signal change up to 30% for f_R0=-1e-5 in the unscreened regime. In contrast, the influence of f(R) on the statistical Lyman-alpha forest properties is rather weak. We plan to extend our analysis to other modified gravity models in future work.
Supervisor: Volker Springel (HITS)