相关论文: Mining The Local Universe for Data: the QSO Lumino…

We present progress results of a new survey for bright QSOs (V<14.5, R<15.4, B_J<15.2) covering the whole sky at high galactic latitudes, |b|>30. The surface density of QSOs brighter than B_J=14.8 turns out to be 2.9 +- 0.8 10^{-3}…

This paper presents the first results of a survey for bright quasars (V < 14.5 and R<15.4) covering the North Hemisphere at galactic latitudes |b|>30. The photometric database is derived from the GSC and USNO catalogs. Quasars are…

An ESO Key programme dedicated to an Homogeneous Bright QSO Survey (HBQS) has been completed. 327 QSOs (Mb<-23, 0.3<z<2.2) have been selected over 555 deg^2 with 15<B<18.75. For B<16.4 the QSO surface density turns out to be a factor 2.2…

An ESO Key programme dedicated to an Homogeneous Bright QSO Survey (HBQS) has been completed. 327 QSOs (Mb<-23, 0.3<z<2.2) have been selected over 555 deg^2 with 15<B<18.75. For B<16.4 the QSO surface density turns out to be a factor 2.2…

We present the QSO luminosity function of the completed 2dF-SDSS LRG and QSO (2SLAQ) survey, based on QSOs photometrically selected from Sloan Digital Sky Survey imaging data and then observed spectroscopically using the 2dF instrument on…

This is the second paper of a series describing the Asiago-ESO/RASS QSO survey, a project aimed at the construction of an all-sky statistically well-defined sample of very bright QSOs (B_J < 15). Such a survey is required to remove the…

The AERQS is a project aimed at the construction of an all-sky statistically well-defined sample of local (z < 0.3) and bright (R < 15.5) QSOs. Present uncertainties on the theoretical modeling of the QSO evolution are to be ascribed to the…

Based on results by recent surveys, the number of bright quasars at redshifts z>3 is being constantly revised upwards. Current consensus is that at bright magnitudes ($M_{1450}\le -27$) the number densities of such sources could have been…

In Paper I (Mickaelian et al. 1999), we compared the surface density of QSOs in the Bright Quasar Survey (BQS) and in the First Byurakan Survey (FBS) and concluded that the completeness of the BQS is of the order of 70% rather than 30-50%…

Aims: In this work the luminosity function of QSOs is measured in the redshift range 3.5<z<5.2 for the absolute magnitude interval -21<M_{145}<-28. The determination of the faint end of the luminosity function at these redshifts provides…

An ESO Key programme dedicated to an Homogeneous Bright QSO Survey (HBQS) has been completed. 327 QSOs (Mb<-23, 0.3<z<2.2) have been selected over 555 deg^2 with 15<B<18.75. For B<16.4 the QSO surface density turns out to be a factor 2.2…

We present the analysis of a new flux-limited sample of bright quasars and Seyfert 1 galaxies in an effective area of 611 square deg, drawn from the Hamburg/ESO survey. We confirm recent claims that bright quasars have a higher surface…

We have analysed the optical luminosity-redshift distribution properties of bright QSOs, using a new large sample from the Hamburg/ESO survey. The sample provides insight into the hitherto poorly sampled bright tail of the luminosity…

Motivated by evidences favoring a rapid and late hydrogen reionization process completing at z~5.2-5.5 and mainly driven by rare and luminous sources, we have reassessed the estimate of the space density of ultra-luminous QSOs at z~5 in the…

We measure the luminosity function of QSOs in the redshift range 3.5 < z < 5.2 for the absolute magnitude interval -21 < M_{145} < -28. Suitable criteria are defined to select faint QSOs in the GOODS fields, checking their effectiveness and…

In the deepest optically identified X-ray survey yet performed, we have identified 32 X-ray selected QSOs to a flux limit of 2x10^{-15} erg cm^{-2} s^{-1} (0.5-2 keV). The survey, performed with the ROSAT PSPC, has 89% spectroscopic…

We present some results from our HST archival image study of 71 QSO host galaxies. The objects are selected to have z < 0.46 and total absolute magnitude M_V < -23 (H_0=50 km/s/Mpc). This initial study investigates host morphology and radio…

We search for ultra-luminous Quasi-Stellar Objects (QSOs) at high redshift using photometry from the SkyMapper Southern Survey Data Release 3 (DR3), in combination with 2MASS, VHS DR6, VIKING DR5, AllWISE, and CatWISE2020, as well as…

This is the third paper of a series describing the Asiago-ESO/RASS QSO survey (AERQS), a project aimed at the construction of an all-sky statistically well-defined sample of relatively bright QSOs (B<15) at z<0.3. We present here the…

In this Paper we present a clustering analysis of QSOs as a function of luminosity over the redshift range z=0.3-2.9. We use a sample of 10566 QSOs taken from the preliminary data release catalogue of the 2dF QSO Redshift Survey (2QZ). We…