The Warm DM halo mass function below the cut-off scale

Understand

Warm Dark Matter (WDM) cosmologies are a viable alternative to the Cold Dark Matter (CDM) scenario.

• Unfortunately, an accurate scrutiny of the WDM predictions with N-body simulations has proven difficult due to numerical artefacts.
• Here, we report on cosmological simulations that, for the first time, are devoid of those problems, and thus, are able to accurately resolve the WDM halo mass function well below the cut-off.
• We discover a complex picture, with perturbations at different evolutionary stages populating different ranges in the halo mass function.