Soft X-ray AGN Luminosity Function from ROSAT Surveys I. Cosmological Evolution and Contribution to the Soft X-ray Background

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dc.creatorMiyaji, Takamitsu
dc.creatorHasinger, Guenther
dc.creatorSchmidt, Maarten
dc.date1999-10-22
dc.date.accessioned2026-07-07T02:33:59Z
dc.date.available2026-07-07T02:33:59Z
dc.descriptionWe investigate the evolution of the 0.5-2 keV soft X-ray luminosity function (SXLF) of active galactic nuclei (AGN) using results from ROSAT surveys of various depth, ranging from shallow large-area ROSAT All-Sky Survey -based samples to the deepest pointed observation on the Lockman Hole. As previously found, the SXLF evolves rapidly as a function of redshift up to z\sim 1.5 and is consistent with remaining constant beyond this redshift. We found that a form of the Luminosity-Dependent Density Evolution (LDDE) gives an excellent fit to the data. Extrapolating one form of the LDDE model (LDDE1) explains \approx 60% of the estimated soft extragalactic Cosmic X-ray Background (CXRB). We have also found another representation (LDDE2), which produces \approx 90% of the CXRB and still gives an excellent fit to the sample AGNs. These two versions of the LDDE models can be considered two extremes of the possible extrapolations of the SXLF below the flux limit. We have also investigated the evolution of the number density of luminous QSOs. Unlike these QSOs, the ROSAT-selected QSOs do not show evidence for the decrease of the number density in z>3. The statistical significance of the difference is, however, marginal.
dc.description18 pages, 12 postscript figures, A&A in press
dc.identifierhttps://arxiv.org/abs/astro-ph/9910410
dc.identifierhttp://arxiv.org/abs/astro-ph/9910410
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/15070
dc.subjectAstrophysics
dc.titleSoft X-ray AGN Luminosity Function from ROSAT Surveys I. Cosmological Evolution and Contribution to the Soft X-ray Background
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