2012/12/25 by Roberta Diamanti, Elena Giusarma, Olga Mena +3 · 54 citations
Physics and Astronomy · #Astronomy #Astrophysics #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Galaxies: Formation, Evolution, Phenomena #Optics #Physics #Radiation #astro-ph.CO #hep-ph
paper · pdf · doi:10.1103/physrevd.87.063509
published in Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields 87(6) (American Physical Society) · 8 pages, 6 figures
arxiv created 2012/12/25 · openalex publication_date 2013/03/07 · arxiv updated 2013/03/13 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
An extra dark radiation component can be present in the universe in the form of sterile neutrinos, axions or other very light degrees of freedom which may interact with the dark matter sector. We derive here the cosmological constraints on the dark radiation abundance, on its effective velocity and on its viscosity parameter from current data in dark radiation-dark matter coupled models. The cosmological bounds on the number of extra dark radiation species do not change significantly when considering interacting schemes. We also find that the constraints on the dark radiation effective velocity are degraded by an order of magnitude while the errors on the viscosity parameter are a factor of two larger when considering interacting scenarios. If future Cosmic Microwave Background data are analyzed assuming a noninteracting model but the dark radiation and the dark matter sectors interact in nature, the reconstructed values for the effective velocity and for the viscosity parameter will be shifted from their standard 1/3 expectation, namely ceff2=0.34_\ensuremath-0.003+0.006 and cvis2=0.29_\ensuremath-0.001+0.002 at 95% C.L. for the future COrE mission data.