TY  - JOUR
AU  - Archidiacono, M.
AU  - Giusarma, E.
AU  - Melchiorri, A.
AU  - Mena, O.
PY  - 2012
DA  - 2012//
TI  - Dark radiation in extended cosmological scenarios
T2  - Phys. Rev. D
JO  - Physical Review D
SP  - 043509
EP  - 7pp
VL  - 86
IS  - 4
PB  - Amer Physical Soc
AB  - Recent cosmological data have provided evidence for a "dark" relativistic background at high statistical significance. Parameterized in terms of the number of relativistic degrees of freedom N-eff, however, the current data seem to indicate a higher value than the one expected in the standard scenario based on three active neutrinos. This dark radiation component can be characterized not only by its abundance but also by its clustering properties, as its effective sound speed and its viscosity parameter. It is therefore crucial to study the correlations among the dark radiation properties and key cosmological parameters, as the dark energy equation of state or the running of the scalar spectral index, with current and future cosmic microwave background data. We find that dark radiation with viscosity parameters different from their standard values may be misinterpreted as an evolving dark energy component or as a running spectral index in the power spectrum of primordial fluctuations.
SN  - 1550-7998
UR  - http://arxiv.org/abs/1206.0109
UR  - https://doi.org/10.1103/PhysRevD.86.043509
DO  - 10.1103/PhysRevD.86.043509
LA  - English
N1  - WOS:000307276500002
ID  - Archidiacono_etal2012
ER  -