Open AccessGlobal fits for the spectral index of the cosmological curvature perturbation
Author(s) -
Covi Laura,
Lyth David H.
Publication year - 2001
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2001.04466.x
Subject(s) - physics , spectral index , cosmic microwave background , hubble's law , cosmology , reionization , astrophysics , cosmic background radiation , baryon , curvature , spectral density , cmb cold spot , galaxy , anisotropy , spectral line , statistics , dark energy , quantum mechanics , redshift , geometry , mathematics
Best‐fitting values of the spectral index of the curvature perturbation are presented, assuming the ΛCDM cosmology. Apart from the spectral index, the parameters are the Hubble parameter, the total matter density and the baryon density. The data points are intended to represent all measurements that are likely to affect the result significantly. The cosmic microwave anisotropy is represented by the COBE normalization, and heights of the first and second peaks are given by the latest Boomerang and Maxima data. The slope of the galaxy correlation function and the matter density contrast on the 8 h −1 Mpc scale are each represented by a data point, as are the expected values of the Hubble parameter and matter density. The ‘low‐deuterium’ nucleosynthesis value of the baryon density provides a final data point, the fit giving a value higher by about one standard deviation. The reionization epoch is calculated from the model by assuming that it corresponds to the collapse of a fraction f≳10 −4 of matter. We consider the case of a scale‐independent spectral index, and also the scale‐dependent spectral index predicted by running mass models of inflation. In the former case, the result is compared with the prediction of models of inflation based on effective field theory, in which the field value is small on the Planck scale. A detailed comparison is made with other fits, and other approaches to the comparison with theory.