I heard an interesting presentation today suggesting that cold dark matter is insufficient to explain the distribution of dwarf galaxies. To explain the structure of the observable universe the prime candidate is warm dark matter.
CDM seems to do quite a good job for explaining the structure and distribution of galaxies but now it fails with dwarf galaxies.
A couple of questions.
The observed power spectra from cosmological simulations indicate a preference for WDM rather than CDM, is this correct? As my background is not cosmology I'm having difficulty in understanding this interprettation of the power spectra.
The power spectrum dependence of dark matter halo concentrations.
surely we're not ruling out CDM (it explains the clumping of galaxies quite well)?
Particle physics hasn't indicated that the candidate is CDM or WDM why can it not be both, after all there
is a range of excitations or supersymmetric candidates or QHD excitations, technicolour excitations etc.... which could form the WDM or CDM candidates.
A couple of links (one quite fun)
Build a universe with CMB