Linear cosmological structure limits on warm dark matter

Constraints on Warm Dark Matter from Cosmological Reionization

We study the constraints that high-redshift structure formation in the universe places on warm dark matter (WDM) dominated cosmological models. We modify the extended Press-Schechter formalism to derive the halo mass function in WDM models. We show that our predictions agree with recent numerical simulations at low redshift over the halo masses of interest. Applying our model to galaxy formatio...

The Cosmological Flatness Problem and Limits on Dark Matter

Limits on WIMP Dark Matter

The current state searches for dark matter in the form of Weakly Interacting Massive Particles (WIMPs) using both direct and indirect techniques is reviewed. Advances in recent years by various direct search experiments, utilising technology able to record the nuclear recoil events expected from elastic scattering by WIMPs, have allowed progress towards lower limits to be made. In particular, t...

Limits on Sparticle Dark Matter

Arguments are given that the lightest supersymmetric particle should be a neutralino χ. Minimizing the fine tuning of the gauge hierarchy favours Ωχh 2 ∼ 0.1. There are important constraints on the parameter space os the MSSM from the stability of the electroweak vacuum. Co-annihilation with the next-to-lightest supersymmetric particle is potentially significant. Incorporating the latest accele...

The imprint of warm dark matter on the cosmological 21-cm signal

We investigate the effects of warm dark matter (WDM) on the cosmic 21-cm signal. If dark matter exists as WDM instead of cold dark matter (CDM), its non-negligible velocities can inhibit the formation of low-mass haloes that normally form first in CDM models, therefore delaying star formation. The absence of early sources delays the build-up of UV and X-ray backgrounds that affect the 21-cm rad...