Found 35 talks width keyword large-scale structure

In this talk, we shall review the impact of the neutrino properties on the different cosmological observables. We shall also present the latest cosmological constraints on the neutrino masses and on the effective number of relativistic species. Special attention would be devoted to the role of neutrinos in solving the present cosmological tensions.

Bosonic ultra-light dark matter (ULDM) in the mass range m ~ $10^{-22} - 10^{-21} \rm eV$ has been invoked as a motivated candidate with new input for the small-scale `puzzles' of cold dark matter. Numerical simulations show that these models form cored density distributions at the center of galaxies ('solitons'). These works also found an empirical scaling relation between the mass of the large-scale host halo and the mass of the central soliton. We show that this relation predicts that the peak circular velocity of the outskirts of the galaxy should approximately repeat itself in the central region. Contrasting this prediction to the measured rotation curves of well-resolved near-by galaxies, we show that ULDM in the mass range m ~ $10^{-22} - 10^{-21} \rm eV$ is in tension with the data.

The expansion of the Universe is in an accelerated phase. This
acceleration was first estabilished by observations of SuperNovae, and
has since been confirmed through a range of independent observations.

The physical cause of this acceleration is coined Dark Energy, and
most observations indicate that Einsteins cosmological constant
provides a very good fit. In that case, approximately 70% of the
energy of the Universe presently consists of this cosmological
constant.

I will in this talk address the possibility that there may exist other
possible causes of the observed acceleration. In particular will I
discuss a concrete model, inspired by the well-known Lorentz force in
electromagnetism, where Dark Matter causes the acceleration.  With a
fairly simple numerical simulation we find that the model appears
consistent with all observations.

In such a model, where Dark Matter properties causes the acceleration
of the Universe, there is no need for a cosmological constant.