Font Size: a A A

Large-scale clustering of radio sources from the Green Bank 1987 survey

Posted on:1996-12-05Degree:Ph.DType:Thesis
University:Princeton UniversityCandidate:Sicotte, HuguesFull Text:PDF
GTID:2468390014486712Subject:Physics
Abstract/Summary:
The fluctuations in the matter density of the Universe are one of the few remnants of the Grand Unified Theory (GUT). The present value of these fluctuations is constrained by the measurements of the angular correlation function of galaxies, while at very early times, at redshifts of {dollar}zsim50-1300{dollar}, they are related to the fluctuations in the cosmic microwave background radiation (CMBR). To constrain models, measurement of these density fluctuations are required at other scales and epochs.; In this thesis we assume that radio sources trace the large-scale density fluctuations as far as a redshift of {dollar}zsim1{dollar} and can thus be used to probe the evolution of the spectrum of density perturbations. The radio data are not yet sufficient to distinguish between various cosmological models, but the techniques we developed should constraint the time evolution of the large-scale structure when used on the ongoing VLA FIRST (Becker, White & Helfand (1995)) and NRAO-VLA NVSS (Condon et al. (1994)) radio surveys, thus giving an indirect measure of {dollar}Omega{dollar}, the density parameter.; We computed the angular auto-correlation of the 1987 Green Bank (87GB) radio survey, as well as the angular cross-correlation of this catalog with Abell clusters, optically selected quasars and IRAS galaxies. Using a bayesian technique the characteristic scale of the spatial clustering, where the spatial correlation function is unity, were calculated for the aforementioned statistics to be respectively {dollar}11pm1.5, 11pm2, <{dollar}5, and {dollar}<{dollar}5Mp{dollar}chsp{lcub}-1{rcub}{dollar}. The fitted mean redshift evolution of the spatial auto-correlation function of the 87GB radio sources is consistent with the interpretation that radio sources cluster with the rich groups or poor clusters of Abell richness 0-1.
Keywords/Search Tags:Radio sources, Fluctuations, Density, Large-scale
Related items