A Quantification of the Butterfly Effect in Cosmological Simulations and Implications for Galaxy Scaling Relations

Understand

We study the chaotic-like behavior of cosmological simulations by quantifying how minute perturbations grow over time and manifest as macroscopic differences in galaxy properties.

• When we run pairs of 'shadow' simulations that are identical except for random minute initial displacements to particle positions (e.g.
• of order 1e-7pc), the results diverge from each other at the individual galaxy level (while the statistical properties of the ensemble of galaxies are unchanged).
• After cosmological times, the global properties of pairs of 'shadow' galaxies that are matched between the simulations differ from each other generally at a level of ~2-25%, depending on the considered physical quantity.