1998/11/13 by E. Ghaffarsedeh, Ghaffarsedeh, E., J. J. Quenby +2
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics (astro-ph) #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #Scientific Research and Discoveries #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9811218
9 pages, 15 figures, LATEX
arxiv created 1998/11/13 · openalex publication_date 1998/11/13 · arxiv updated 2019/08/17 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Clustering properties of two samples of X-ray selected AGNs are compared with IR/Optical galactic samples. These are the Einstein Observatory Extended Medium Sensitivity Survey: EMSS; and a sample of 654 ROSAT detected radio quasars. The cosmological dipole moment is calculated for these samples, yielding the values of b Ωo-0.6. We find this factor to be 0.68 ± 0.22 for the EMSS sample, and 1.02 ± 0.014 for the quasars sample. Comparing these values with that of the IRAS 1.2 Jy sample (1.95 ± 0.096), suggests that these AGNs are less clustered than the IRAS galaxies. For each sample there is a depth at which the amplitude of the dipole growth curve saturates. This convergence radius (Rconv) is found to be ∼ 300-400 h-1 Mpc for the EMSS sample and ∼ 450-500 h-1 Mpc for the ROSAT detected quasars sample, which suggests that X-ray AGNs have a much deeper contribution to the Local Group (LG) motion compared to the galaxy and cluster samples. Using the properties of the angular and spatial correlation functions for these samples, we find: bIRAS/bquasars = 3.61 ± 2.7; bIRAS/bEMSS= 8.46 ± 6.4 and bquasars / bEMSS = 2.35 ± 0.2. Using Chi-squared minimisation, we have fitted the angular correlation functions using the standard power law model of the form: W(θ)= A θ-δ, and the spatial correlation functions using the power law model of the form: ξ(r) =(r/r0)-γ. For the angular correlation functions, we find A ∼0.6 for the AGN auto-correlations and A ∼0.2-0.3 for the AGN-IRAS galaxy cross-correlations. Also δ is found to be ~ 0.8-1.1. In the spatial correlation analysis, we find ro∼3.5-5.1 h-1Mpc and γ∼1.4-1.7 .