Expectations for the angular correlation function of intensity fluctuations of the extragalacitc 2-10 keV X-ray background are discussed in relation to the two-point spatial correlation functions, xi(r), of X-ray sources. A simple analytic formula for the amplitude of intensity correlations, Gamma(theta), holding in the low-redshift, small-separation approximation, is derived. The HEAO 1 A-2 upper limits on Gamma(theta) have been exploited to derive constraints on the local xi(r) functions of rich clusters of galaxies, of AGNs, and on the AGN-cluster cross-correlation, as well as on evolution of the correlation functions with cosmic time. X-ray data are found to be compatible with the Bahcall and Soneira estimates of xi(cluster-cluster) as well as with the results of recent studies of quasar clustering.
|Titolo:||CONSTRAINTS ON LARGE-SCALE CLUSTERING FROM THE AUTOCORRELATION PROPERTIES OF THE X-RAY-BACKGROUND|
|Autori:||Dezotti, G; Persic, M; Franceschini, A; Danese, Luigi; Palumbo, Ggc; Boldt, Ea; Marshall, Fe|
|Data di pubblicazione:||1990|
|Digital Object Identifier (DOI):||10.1086/168440|
|Fulltext via DOI:||http://adsabs.harvard.edu/full/1990ApJ...351...22D|
|Appare nelle tipologie:||1.1 Journal article|