8 cMpc/h sub-region of the simulation, at z=7.3. White : gas density. Blue : ionizing photon density. Red : hot gas, heated by supernovae and shocks.

Cosmic Dawn III (CoDa III) is the latest iteration of the cosmological simulations of the EoR developed at the Observatoire astronomique de Strasbourg. It was run on Summit at the Oak ridge Leadership Computing Facility, the most powerful computing center in the world until June 2020. It required 131072 CPUs, 24576 GPUs, and produced roughly 20 PB of data !

Alongside gravity, hydrodynamics, star formation, and radiative transfer, the ~94 cMpc simulation includes processes such as supernovae feedback and chemical enrichment. The mass resolution in CoDa III is 8 times finer than in CoDa II (2020) which allows for a better description of galactic haloes and absorbers in the intergalactic medium. Coda III features improved models for star formation, ionizing emissivity, and dust, with respect to CoDa II.

Movies of the evolution of the simulation on different scales are available on Pierre Ocvirk’s Youtube Channel.

Ref : Lewis, J. S., Ocvirk, P., et al (2022). The short ionizing photon mean free path at z= 6 in Cosmic Dawn III, a new fully-coupled radiation-hydrodynamical simulation of the Epoch of Reionization. arXiv preprint arXiv:2202.05869.

Credits : P. Ocvirk, D. Aubert, J. Lewis, N. Gillet, J. Chardin

.