On Robustness in Cosmological Simulations

Marie Gueguen Marie G.

Abstract:  While the Cold Dark Matter model is well supported by evidence on large scales, it does not fare well on small scales, where simulations do not reproduce the observed abundance and demographics of dark matter halos. Since these properties are the prime discriminators between different dark matter models, predicting them accurately is crucial for determining the nature of dark matter. At such a scale though, only numerical approaches to determining them are possible; and understanding in which case a simulation can succeed in (dis)confirming a model is still a challenge. In other disciplines, such as biology, this question has been addressed through robustness analysis. In this talk, I will argue that robustness is not a sufficient criterion for determining when a simulation is reliable and that alternatives to robustness should be pursued. I motivate the use of crucial simulations, meant to put the numerical or physical origin of a prediction under a crucial test.