Open AccessThe cluster abundance in cosmic string models for structure formation
Author(s) -
Avelino P. P.,
Wu J. H. P.,
Shellard E. P. S.
Publication year - 2000
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.1365-8711.2000.03556.x
Subject(s) - physics , cosmic string , sigma , normalization (sociology) , astrophysics , amplitude , cosmic cancer database , inflation (cosmology) , gaussian , primordial fluctuations , dark matter , cosmological constant , exponential function , cosmology , cosmic variance , string (physics) , cosmic microwave background , mathematical physics , theoretical physics , quantum mechanics , galaxy , mathematical analysis , mathematics , anisotropy , sociology , anthropology , redshift
We use the present observed number density of large X‐ray clusters to constrain the amplitude of matter density perturbations induced by cosmic strings on the scale of 8 h −1 Mpc ( σ 8 ), in both open cosmologies and flat models with a non‐zero cosmological constant. We find a slightly lower value of σ 8 than that obtained in the context of primordial Gaussian fluctuations generated during inflation. This lower normalization of σ 8 results from the mild non‐Gaussianity on cluster scales, where the one‐point probability distribution function is well approximated by a χ 2 distribution and thus has a longer tail than a Gaussian distribution. We also show that σ 8 normalized using cluster abundance is consistent with the COBE normalization.