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The case for non‐Gaussianity on cluster scales
Author(s) -
Mathis H.,
Diego J. M.,
Silk J.
Publication year - 2004
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 - 10.1111/j.1365-2966.2004.08110.x
Subject(s) - physics , cosmic microwave background , astrophysics , non gaussianity , gaussian , spectral density , cluster (spacecraft) , cosmic background radiation , redshift , primordial fluctuations , normalization (sociology) , statistical physics , statistics , galaxy , quantum mechanics , mathematics , sociology , anthropology , anisotropy , computer science , programming language
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.

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