A deep ROSAT survey - IV. The evolution of X-ray-selected QSOs

Abstract

We report on a new estimate of the QSO X-ray luminosity function and its evolution with redshift based on a sample of 107 QSOs detected at faint X-ray fluxes, $S(0.5-2\mathrm{keV})>4\times 10^{-15}$\ergcms , with the {\it ROSAT} X-ray satellite. For $q_0=0.5$, the X-ray evolution of QSOs in this sample is consistent with strong luminosity evolution, $L_{\mathrm{X}}^{\ast }(z)\propto (1+z{)}^{3.25\pm 0.1}$, at low redshifts ($z<1.60$) and a constant comoving space density at higher redshifts. The derived rate of evolution at low redshifts is thus significantly higher than that obtained previously for the {\it Einstein} Extended Medium Sensitivity Survey (EMSS). Indeed, most luminosity evolution models provide a very poor fit (rejected at the 99 per cent confidence level) when applied to the combined EMSS and {\it ROSAT} samples, although a polynomial evolution model, $L_{\mathrm{X}}^{\ast }(z)\propto 10^{(1.14z-0.23z^2)}$, provides an adequate fit for $q_0=0$. For $q_0=0.5$, a simple power-law luminosity evolution model with a redshift cut-off ($L_{\mathrm{X}}^{\ast }(z)\propto (1+z{)}^{2.51\pm 0.1}$,

Accepted for publication in MNRAS. 10 pages including 4 figures; uuencoded compressed postscript; RGO-209

Cited by in corpus (39)

• The synthesis of the cosmic X-ray background in the Chandra and XMM-Newton era
• X-ray emission from radio-quiet quasars in the SDSS Early Data Release. The alpha_ox dependence upon UV luminosity
• Tracing the large scale structure in the Chandra Deep Field South
• The Fall of the Quasar Population
• The spatial clustering of X-ray selected AGN and galaxies in the Chandra Deep Field South and North
• The BeppoSAX High Energy Large Area Survey HELLAS, III: testing synthesis models for the X-ray background
• The ELAIS Deep X-ray Survey I: Chandra Source Catalogue and First Results
• Correlations Between the Cosmic X-ray and Microwave Backgrounds: Constraints on a Cosmological Constant
• X-ray variability in a deep, flux limited sample of QSOs
• The XMM-Newton Serendipitous Survey. II. First results from the AXIS high galactic latitude medium sensitivity survey
• On the redshift cut-off for flat-spectrum radio sources
• AGN contamination of galaxy-cluster thermal X-ray emission: predictions for eRosita from cosmological simulations
• The REX survey: a search for Radio Emitting X-ray sources
• Compton Heating of the Intergalactic Medium by the Hard X-ray Background
• The 5 - 10 keV AGN luminosity function at 0.01<z<4.0
• A Medium Survey of the Hard X-Ray Sky with ASCA. II.: The Source's Broad Band X-Ray Spectral Properties
• The soft X-ray background: evidence for widespread disruption of the gas halos of galaxy groups
• The X-ray surface brightness distribution from diffuse gas
• The XMM-Newton/2dF survey I: X-ray properties of normal galaxies
• The Asiago-ESO/RASS QSO Survey. I.The Catalog and the Local QSO Luminosity Function
• The Evolution of Radio Galaxies at Intermediate Redshift
• New Constraint on Open Cold-Dark-Matter Models
• The 2-10 keV unabsorbed luminosity function of AGN from the XMM-Newton LSS, CDFS and COSMOS surveys
• X-ray Spectra of the RIXOS source sample
• Cosmological Evolution of Quasars
• Constraints on the distribution of absorption in the X-ray selected AGN population found in the 13H XMM-Newton/Chandra deep field
• The X-ray luminosity function of local galaxies
• The XXL Survey XIX. A realistic population of simulated X-ray AGN: Comparison of models with observations
• The BeppoSAX High Energy Large Area Survey. IV. On the soft X-ray properties of the hard X-ray-selected HELLAS sources
• On the Origin of the Hard X-Ray Background
• The diffuse X-ray background
• Determining the cosmological parameters from the linewidths of active galaxies
• Cross-correlation of the 2-10 keV XRB with radio sources: constraining the large-scale structure of the x-ray background
• Faint galaxies and the X-ray background
• The VST ATLAS Quasar Survey I: Catalogue
• The luminosity dependence of opening angle in unified models of active galaxies
• Finding Gravitational Lenses With X-rays
• A new X-ray mission to measure the power spectrum of fluctuations in the Universe
• Probing properties of nearly two-hundred new active galactic nuclei