The BeppoSAX High Energy Large Area Survey -V. The nature of the hard X-ray source populations and its evolution

Abstract

We present optical spectroscopic identifications of hard X-ray (5-10 keV) selected sources belonging to the HELLAS sample obtained with BeppoSAX down to a 5-10 keV flux limit of f_{5-10 keV}~3x10^-14 erg cm^-2 s^-1. The sample consists of 118 sources. 25 sources have been identified trough correlations with catalogues of known sources. 49 have been searched for spectroscopic identification at the telescope. 13 fields resulted empty down to R=21. 37 sources have been identified with type 1 AGN and 9 with type 2 AGN. The remaining are: 5 narrow emission line galaxies, 6 Clusters, 2 BL Lac, 1 Radio Galaxy and 1 Star. Combining these objects with other hard X-ray selected AGNs from ASCA and HEAO1, we find that the local luminosity function of type 1 AGN in the 2-10 keV band is fairly well represented by a double-power-law-function. There is evidence for significant cosmological evolution according to a pure luminosity evolution (PLE) model L_X(z)~(1+z)^k, with k=2.12 and k=2.22 in a (Omega_m,Omega_lambda)=(1.0,0.0) and in a (Omega_m,Omega_lambda)=(0.3,0.7) cosmology, respectively. The data show an excess of faint high redshift type 1 AGN which is well modeled by a luminosity dependent density evolution (LDDE), similarly to what observed in the soft X-rays. However, in both cosmologies, the statistic is not significant enough to distinguish between the PLE and LDDE models. The fitted models imply a contribution of AGN1 to the 2-10 keV X-ray background from 35% up to 60%.

arXiv comment16 pages, 12 figures. Emulateapj version. To appear on ApJ, v570, May 1 2002

References in corpus (22)

• The 2dF QSO Redshift Survey - I. The Optical QSO Luminosity Function
• First Results from the X-ray and Optical Survey of the Chandra Deep Field South
• Resolving the extragalactic hard X-ray background
• XMM-Newton observation of the Lockman Hole; I. The X-ray Data
• The Chandra Deep Survey of the Hubble Deep Field North Area. II. Results from the Caltech Faint Field Galaxy Redshift Survey Area
• The Nature of the Hard X-ray Background Sources: Optical, Near-infrared, Submillimeter, and Radio Properties
• X-ray Observations of Optically-Selected, Radio-Quiet Quasars I: The ASCA results
• New Results from the X-ray and Optical Survey of the Chandra Deep Field South: The 300ks Exposure
• Optical Identification of the ASCA Large Sky Survey
• The HELLAS2XMM survey: I. The X-ray data and the Log(N)-Log(S)
• The contribution of faint AGN to the hard X-ray background
• The Canada-France Redshift Survey XII: Nature of emission-line field galaxy population up to z = 0.3
• Spectroscopic identification of ten faint hard X-ray sources discovered by Chandra
• The BeppoSAX High Energy Large Area Survey HELLAS, III: testing synthesis models for the X-ray background
• The QSO evolution derived from the HBQS and other complete QSO surveys
• The XMM-Newton Serendipitous Survey. II. First results from the AXIS high galactic latitude medium sensitivity survey
• The BeppoSAX High Energy Large Area Survey HELLAS, II: Number counts and X-ray spectral properties
• ASCA observations of Deep ROSAT fields - II. The 2-10keV AGN luminosity function
• ASCA observations of deep ROSAT fields I. the nature of the X-ray source populations
• Soft versus Hard X-ray emission in AGN: partial covering and warm plus cold absorber models
• The BeppoSAX High Energy Large Area Survey. IV. On the soft X-ray properties of the hard X-ray-selected HELLAS sources
• An X-ray and optical study of the cluster A33

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• Early Black Holes in Cosmological Simulations: Luminosity Functions and Clustering Behaviour
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