The HELLAS2XMM survey: IV. Optical identifications and the evolution of the accretion luminosity in the Universe

Abstract

We present results from the photometric and spectroscopic identification of 122 X-ray sources recently discovered by XMM-Newton in the 2-10 keV band (the HELLAS2XMM 1dF sample). Their flux cover the range 8E-15-4E-13 cgs and the total area surveyed is 0.9 deg2. About 20% of the hard X-ray selected sources have an X-ray to optical flux ratio (X/O) ten times or more higher than that of optically selected AGN. Unlike the faint sources found in the ultra-deep Chandra and XMM-Newton surveys, which reach X-ray (and optical) fluxes more than one order of magnitude lower than the HELLAS2XMM survey sources, many of the extreme X/O sources in our sample have R<=25 and are therefore accessible to optical spectroscopy. We report the identification of 13 sources with X/O>10: 8 are narrow line QSO (i.e. QSO2), four are broad line QSO. We use a combined sample of 317 hard X-ray selected sources (HELLAS2XMM 1dF, CDFN 1Msec, SSA13 and Lockman Hole flux limited samples), 221 with measured z, to evaluate the cosmological evolution of the hard X-ray source's number and luminosity densities. Looking backward in time, the low luminosity sources (logL(2-10keV) = 43-44 erg/s) increase in number at a rate different than the high luminosity sources (logL(2-10keV)>44.5 erg/s), reaching a maximum around z=1 and then levelling off beyond z=2. This translates into an accretion driven luminosity density which is dominated by sources with logL(2-10keV) < 44.5 erg/s up to at least z=1, while the contribution of the same sources and of those with logL(2-10keV)>44.5 erg/s appear to be comparable between z=2 and 4.

arXiv commentv2, minor changes, A&A in press

References in corpus (38)

• A Fundamental Relation Between Supermassive Black Holes and Their Host Galaxies
• High Redshift Galaxies in the Hubble Deep Field. Color Selection and Star Formation History to z=4
• The Star Formation History of Field Galaxies
• The Chandra Deep Field South: the 1 Million Second
• The Soft X-Ray Properties of a Complete Sample of Optically Selected Quasars II. Final Results
• First Results from the X-ray and Optical Survey of the Chandra Deep Field South
• The CANADA-FRANCE REDSHIFT SURVEY VI: Evolution of the galaxy luminosity function to z ~ 1
• Resolving the extragalactic hard X-ray background
• XMM-Newton observation of the Lockman Hole; I. The X-ray Data
• The Chandra Deep Field North Survey. V. 1 Ms Source Catalogs
• Most Supermassive Black Holes must be Rapidly Rotating
• The mass density in black holes inferred from the X-ray background
• Joint Formation of QSOs and Spheroids: QSOs as clocks of star formation in Spheroids
• X-ray, Optical, and Infrared Imaging and Spectral Properties of the 1 Ms Chandra Deep Field North Sources
• 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
• XMM-Newton observation of the Lockman Hole II. Spectral analysis
• The Chandra Deep Field North Survey. VI. The Nature of the Optically Faint X-ray Source Population
• The Redshift Evolution of the 2-8 keV X-ray Luminosity Function
• The HELLAS2XMM survey: II. Multiwavelength observations of P3: an X-ray bright, optically inactive galaxy
• The ROSAT Deep Survey: VI. X-ray sources and Optical identifications of the Ultra Deep Survey
• Optical Identification of the ASCA Large Sky Survey
• The HELLAS2XMM survey: I. The X-ray data and the Log(N)-Log(S)
• The Fall of the Quasar Population
• On the Relationship between Galaxy Formation and Quasar Evolution
• R-Mode Oscillations and Spindown of Young Rotating Magnetic Neutron Stars
• The contribution of faint AGN to the hard X-ray background
• 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
• Quasar Evolution Driven by Galaxy Encounters in Hierarchical Structures
• The XMM-Newton Serendipitous Survey. II. First results from the AXIS high galactic latitude medium sensitivity survey
• The BeppoSAX High Energy Large Area Survey -V. The nature of the hard X-ray source populations and its evolution
• The Hellas2XMM survey: III. Multiwavelength observations of hard X-ray selected sources in the PKS 0312-77 field
• Origin of the X-Ray Background and AGN Unification: New Perspectives
• A Medium Survey of the Hard X-Ray Sky with ASCA. II.: The Source's Broad Band X-Ray Spectral Properties
• The BeppoSAX High Energy Large Area Survey HELLAS, II: Number counts and X-ray spectral properties
• High redshift evolution of optically and IR-selected galaxies: a comparison with CDM scenarios
• Survey of the Tachyonic Lump in Bosonic String Field Theory

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