literature

Constraints on the cosmic neutrino background

Feb, 2003
4 pages
Published in:
  • Mon.Not.Roy.Astron.Soc. 342 (2003) L63
e-Print:

Citations per year

200320062009201220150510152025
Abstract: (arXiv)
The radiative component of the Universe has a characteristic impact on both large scale structure (LSS) and the cosmic microwave background radiation (CMB). We use the recent WMAP data, together with previous CBI data and 2dF matter power spectrum, to constrain the effective number of neutrino species NeffN_{eff} in a general Cosmology. We find that Neff=4.31N_{eff}=4.31 with a 95 per cent C.L. 1.6Neff7.11.6 \le N_{eff} \le 7.1. If we include the H0H_0 prior from the HST project we find the best fit Neff=4.08N_{eff}=4.08 and 1.90Neff6.621.90 \le N_{eff} \le 6.62 for 95 per cent C.L. The curvature we derive is still consistent with flat, but assuming a flat Universe from the beginning implies a bias toward lower NeffN_{eff}, as well as artificially smaller error bars. Adding the Supernovae constraint doesn't improve the result. We analyze and discuss the degeneracies with other parameters, and point out that probes of the matter power spectrum on smaller scales, accurate independent σ8\sigma_8 measurements, together with better independent measurement of H0H_0 would help in breaking the degeneracies.
  • cosmic background radiation: anisotropy
  • neutrino: flavor
  • matter: spectrum
  • radiation: spectrum
  • numerical calculations: interpretation of experiments