skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: BREAKING THE {sigma}{sub 8}-{Omega} {sub m} DEGENERACY USING THE CLUSTERING OF HIGH-z X-RAY ACTIVE GALACTIC NUCLEI

Journal Article · · Astrophysical Journal Letters
 [1];  [2]
  1. Research Center for Astronomy and Applied Mathematics, Academy of Athens, Soranou Efessiou 4, GR-11527 Athens (Greece)
  2. Institute of Astronomy and Astrophysics, National Observatory of Athens, Palaia Penteli 152 36, Athens (Greece)

The clustering of X-ray selected active galactic nuclei (AGNs) appears to be a valuable tool for extracting cosmological information. Using the recent high-precision angular clustering results of {approx}30,000 XMM-Newton soft (0.5-2 keV) X-ray sources, which have a median redshift of z {approx} 1, and assuming a flat geometry, a constant in comoving coordinates AGN clustering evolution, and the AGN bias evolution model of Basilakos et al., we manage to break the {sigma}{sub 8}-{Omega} {sub m} degeneracy. The resulting cosmological constraints are {Omega} {sub m} = 0.27{sup +0.03} {sub -0.05}, w = -0.90{sup +0.10} {sub -0.16}, and {sigma}{sub 8} = 0.74{sup +0.14} {sub -0.12}, while the dark matter host halo mass, in which the X-ray selected AGNs are presumed to reside, is M = 2.50{sup +0.50} {sub -1.50} x 10{sup 13} h {sup -1} M {sub sun}. For the constant {Lambda} model (w = -1) we find {Omega} {sub m} = 0.24 {+-} 0.06 and {sigma}{sub 8} = 0.83{sup +0.11} {sub -0.16}, in good agreement with recent studies based on cluster abundances, weak lensing, and the cosmic microwave background, but in disagreement with the recent bulk flow analysis.

OSTI ID:
21448907
Journal Information:
Astrophysical Journal Letters, Vol. 714, Issue 2; Other Information: DOI: 10.1088/2041-8205/714/2/L185; ISSN 2041-8205
Country of Publication:
United States
Language:
English