Related papers: X-ray QSO evolution from a very deep ROSAT survey
The X-ray luminosity function is an important statistic of the census of galaxy clusters and an important means to probe the cosmological model of our Universe. Based on our recently completed REFLEX II cluster sample we construct the X-ray…
We explore the evolution of the X-ray luminosity function of quasars and the intrinsic correlation between the X-ray and 2500\AA $\,$ ultraviolet luminosities, utilizing techniques verified in previous works and a sample of over 4000…
We have constructed a large, statistically complete sample of galaxy clusters serendipitously detected as extended X-ray sources in 647 ROSAT PSPC pointed observations. The survey covers 158 square degrees with a median sample flux limit of…
The recently-finished Edinburgh UVX quasar survey at B < 18 is used together with other complete samples to estimate the shape and evolution of the optical luminosity function in the redshift range 0.3 < z < 2.2. There is a significantly…
We report measurements of the cluster X-ray luminosity function out to z=0.8 based on the final sample of 201 galaxy systems from the 160 Square Degree ROSAT Cluster Survey. There is little evidence for any measurable change in cluster…
We present XMM-Newton data centered on one of the MUNICS Near Infrared Cluster Survey fields (S2F1) and we discuss the X-ray properties of the 6 X-ray emitting EROs found. For one of them we have already obtained the redshift using…
We investigate spectroscopic properties of galaxy systems identified based on deep X-ray observations in the COSMOS field. The COSMOS X-ray system catalog we use George et al. (2011) includes 180 X-ray systems to a limiting flux of $1.0…
We describe the execution and data reduction of the European Southern Observatory Large Programme "Quasars and their absorption lines: a legacy survey of the high-redshift universe with VLT/XSHOOTER" (hereafter `XQ-100'). XQ-100 has…
We present the X-ray luminosity function (XLF) of the ROSAT Brightest Cluster Sample (BCS), an X-ray selected, flux limited sample of 172 clusters of galaxies at $z\leq 0.3$ compiled from ROSAT All-Sky Survey data. While the bulk of the BCS…
The SDSS-IV/eBOSS has an extensive quasar program that combines several selection methods. Among these, the photometric variability technique provides highly uniform samples, unaffected by the redshift bias of traditional optical-color…
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…
We present and discuss the X-ray luminosity function (XLF) of the ROSAT Brightest Cluster sample (BCS), an X-ray flux limited sample of clusters of galaxies in the northern hemisphere compiled from ROSAT All-Sky Survey data. The BCS allows…
We describe some of the first X-ray detections of groups of galaxies at high redshifts (z~0.4), based on the UK deep X-ray survey of McHardy et al (1998). Combined with other deep ROSAT X-ray surveys with nearly complete optical…
We have utilized the largest sample of $\gamma$-ray selected Fermi flat-spectrum radio quasars (FSRQs) ever used (519 sources) to construct the luminosity function and its evolution through the cosmic history. In addition to spanning large…
We present results from two surveys for radio-loud quasars. These are (1) a northern survey reaching S(5GHz)=0.2Jy and (2) the Parkes QSO survey reaching S(2.7GHz)=0.25Jy, which together cover most of the sky. Both surveys use digitised…
The recent compilation of quasar (QSO) X-ray and UV flux measurements include QSOs that appear to not be standardizable via the X-ray luminosity and UV luminosity ($L_X-L_{UV}$) relation and so should not be used to constrain cosmological…
With approximately 6000 QSO redshifts,the 2dF QSO redshift survey is already the biggest complete QSO survey. The aim for the survey is to have 25000 QSO redshifts, providing an order of magnitude increase in QSO clustering statistics. We…
Recent studies of QSOs with ROSAT suggest the existence of a significant population of Soft X-ray Weak QSOs (SXW QSOs) where the soft X-ray flux is ~ 10-30 times smaller than in typical QSOs. As a first step in a systematic study of these…
We present new results on the cosmological evolution of unabsorbed (type-1) active galactic nuclei (AGN) selected in the soft (0.5-2 keV) X-ray band. From a variety of ROSAT, XMM-Newton and Chandra surveys we selected a total of ~1000 AGN…
We use the ROSAT Deep Cluster Survey (RDCS) to trace the evolution of the cluster abundance out to $z\simeq 0.8$ and constrain cosmological models. We resort to a phenomenological prescription to convert masses into $X$-ray fluxes and apply…