Relic Neutrinos and the Density of the Universe
May, 198031 pages
Published in:
- Astrophys.J. 243 (1981) 1
DOI:
Report number:
- BA-80-19
Citations per year
Abstract: (ADS)
Relic neutrinos will be abundant today (nnu ≈ ngamma) and could, if they have a small mass (mnu ≳ 1.4eV), dominate the universal mass density. Ordinary matter (nucleons) appears to be incapable of accounting for the dynamically inferred mass on scales of clusters of galaxies; recent indications suggest that this problem may persist down to the scale of binary galaxies and small groups of galaxies. The difficulty is that, were the mass on these scales in nucleons, too much helium and too little deuterium would have been produced during primordial nucleosynthesis. Light neutrinos with mnu ≲ 4 eV will remain unclustered but could supply a nonnegligible contribution to the total mass density if 1 eV. Heavy neutrinos with mnu ≳ 20 eV could have collapsed along with galaxies and, unless there were a subsequent segregation of nucleonic matter from neutrinos, would contribute too much invisible mass on such scales. Relic neutrinos with 4 ≲ mnu ≲ 20 eV could supply most of the unseen mass on scales ranging from binaries through small groups to large clusters. Such neutrinos will dominate the mass of the universe and, along with ordinary nucleons, could come close to closing the universe without violating the nucleosynthesis constraints.- NEUTRINO: ASTROPHYSICS
- NEUTRINO: MASS
- MASS: NEUTRINO
- NEUTRINO: LIFETIME
- MODEL: CLUSTER
- NUCLEON: MASS
- MASS: NUCLEON
- THERMODYNAMICS
- MATTER
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