1994/01/11 by Andrew R. Liddle, Liddle, Andrew R, David H. Lyth +1
Physics and Astronomy · #Astrophysics (astro-ph) #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Particle physics theoretical and experimental studies
paper · pdf · doi:10.48550/arxiv.astro-ph/9401014
openalex publication_date 1994/01/11 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We address the possibility of bounding the spectral index n of primordial density fluctuations, using both the cosmic microwave background (cmb) anisotropy and data on galaxies and clusters. Each piece of galaxy and cluster data is reduced to a value of σ(R) (the linearly evolved \em rms density contrast with top hat smoothing on scale R) which allows data on different scales to be readily compared. As a preliminary application, we normalise the spectrum using the ten degree variance of the COBE data, and then compare the prediction with a limited sample of low energy data, for the MDM model with various values of n, Ων and h. With h=.5, the data constrain the spectral index to the range 0.7\lsim n \lsim 1.2. If gravitational waves contribute to the cmb anisotropy with relative strength R=6(1-n) (as in some models of inflation), the lower limit on n is increased to about 0.85. The uncertainty in h widens this band by about 0.1 at either end.