2004/02/29 by H. Mathis, J. M. Diego, Joseph Silk
Physics and Astronomy · #Astrophysics #Cluster (spacecraft) #Cosmic background radiation #Cosmic microwave background #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #Galaxy #Gaussian #Non-Gaussianity #Normalization (sociology) #Physics #Primordial fluctuations #Quantum mechanics #Redshift #Scientific Research and Discoveries #Spectral density #Statistical physics #Statistics #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2004.08110.x
published as Mon.Not.Roy.Astron.Soc. 353 (2004) 681 · 9 pages, 9 figures, submitted to MNRAS, references added and minor changes
arxiv created 2004/03/09 · openalex publication_date 2004/09/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We address whether possible scale-dependent deviations from Gaussianity in the primordial density field that are consistent with the cosmic microwave background observations could explain the apparent excess of early cluster formation at high redshift. Using two phenomenological non-Gaussian models we find that at fixed normalization to the observed local abundance of massive clusters, the protoclusters observed at z∼ 4 are significantly more likely to develop in strongly non-Gaussian models than in the Gaussian paradigm. We compute the relative z < 1 evolution of X-ray cluster counts in the non-Gaussian case with respect to the Gaussian expectation, and the relative excess contribution to the cosmic microwave background (CMB) power spectrum due to the integrated thermal Sunyaev–Zel'dovich (SZ) effect. We find that both the observed hints of an unexpectedly slow evolution in the X-ray counts and the excess power at high ℓ that may have been observed by CMB interferometers can also be reproduced in our non-Gaussian simulations.