Neutrino and Dark Radiation properties in light of recent CMB observations

Title: Neutrino and Dark Radiation properties in light of recent CMB observations

Presenter: Maria Archidiacono (Aarhus U)

Chair: Enrique Fernández-Martinez (UAM Madrid)

Abstract:In this presentation I will illustrate a joint work with Elena Giusarma, Olga Mena and Alessandro Melchiorri. After introducing the Cosmic Neutrino Background, I will briefly describe the neutrino effects on the cosmological observables.

Thanks to these effects we can derive constraints on neutrino physics and dark radiation from cosmological data. Here I will show the results obtained with the nine year data release of the Wilkinson Microwave Anisotropy Probe satellite and with the high-l CMB data of the South Pole Telescope and Atacama Cosmology Telescope experiments, combined with other cosmological probes such as Baryon Acoustic Oscillation, Hubble Space Telescope measurements and Supernovae Ia. Our analyses investigated a large number of different cosmological scenarios, including not only massive neutrinos and additional relativistic degrees of freedom, but also a running of the scalar spectral index or a varying dark energy equation of state parameter. Finally I will discuss the discrepancy between ACT and SPT concerning extra dark radiation and massive neutrinos, and we will see how this discrepancy can be alleviated or worsened by adding external data sets or extending the cosmological model.