Related papers: A new assessment of the completeness of quasar sur…

We investigate the high-redshift quasar luminosity function (QLF) down to an apparent magnitude of I(AB) = 25 in the Cosmic Evolution Survey (COSMOS). Careful analysis of the extensive COSMOS photometry and imaging data allows us to…

Recent studies have derived quasar luminosity functions (QLFs) at various redshifts. However, the faint side of the QLF at high redshifts is still too uncertain. An accurate estimate of the survey completeness is essential to derive an…

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 present the Lyman-$\alpha$ (Ly$\alpha$) and ultraviolet (UV) luminosity function (LF), in bins of redshift, of quasars selected in the Physics of the Accelerating Universe Survey (PAUS). A sample of 915 objects was selected at…

Understanding the faint end of quasar luminosity function at a high redshift is important since the number density of faint quasars is a critical element in constraining ultraviolet (UV) photon budgets for ionizing the intergalactic medium…

We present a well-designed sample of more than 1000 type 1 quasars at $3.5<z<5$ and derive UV quasar luminosity functions (QLFs) in this redshift range. These quasars were selected using the Sloan Digital Sky Survey (SDSS) imaging data in…

This is the second paper in a series on a new luminous z ~ 5 quasar survey using optical and near-infrared colors. Here we present a new determination of the bright end of the quasar luminosity function (QLF) at z ~ 5. Combined our 45 new…

We report the result of a faint quasar survey in a one square degree field. The aim is to test the Y-K/g-z and J-K/i-Y color selection criteria for quasars at faint magnitude, to obtain a complete sample of quasars based on deep optical and…

We present a measurement of the quasar luminosity function in the range 0.68<z<4 down to extinction corrected magnitude g_dered=22.5, using a simple and well understood target selection technique based on the time-variability of quasars.…

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…

This is the fourth paper in a series aimed at finding high-redshift quasars from five-color imaging data taken along the Celestial Equator by the SDSS. during its commissioning phase. In this paper, we use the color-selected sample of 39…

We present new measurements of the quasar luminosity function (LF) at $z \sim 6$, over an unprecedentedly wide range of the rest-frame ultraviolet luminosity $M_{1450}$ from $-30$ to $-22$ mag. This is the fifth in a series of publications…

We study the redshift evolution of the quasar UV Luminosity Function (LF) for 0.5 < z < 6.5, by collecting the most up to date observational data and, in particular, the recently discovered population of faint AGNs. We fit the QSO LF using…

We have used the 2dF instrument on the AAT to obtain redshifts of a sample of z<3, 18.0<g<21.85 quasars selected from SDSS imaging. These data are part of a larger joint programme: the 2dF-SDSS LRG and QSO Survey (2SLAQ). We describe the…

The observed lensed fraction of high-redshift quasars $(\sim0.2\%)$ is significantly lower than previous theoretical predictions $(\gtrsim4\%)$. We revisit the lensed fraction of high-redshift quasars predicted by theoretical models, where…

We present the quasar luminosity function (LF) at $z = 7$, measured with 35 spectroscopically confirmed quasars at $6.55 < z < 7.15$. The sample of 22 quasars from the Subaru High-$z$ Exploration of Low-Luminosity Quasars (SHELLQs) project,…

We searched for quasars that are ~ 3 mag fainter than the SDSS quasars in the redshift range 3.7 < z < 4.7 in the COSMOS field to constrain the faint end of the quasar luminosity function. Using optical photometric data, we selected 31…

We present the quasar luminosity function at $z \sim 5$ derived from the optical wide-field survey data obtained as a part of the Subaru strategic program (SSP) with Hyper Suprime-Cam (HSC). From $\sim$81.8 deg$^2$ area in the Wide layer of…

Around 70 $z>6.5$ luminous quasars have been discovered, strongly biased toward the bright end, thus not providing a comprehensive view on quasar abundance beyond cosmic dawn. We present the predicted results of Roman/Rubin high-redshift…

We place a limit on the logarithmic slope of the luminous quasar luminosity function at z~6 of beta>-3.0 (90%) using gravitational lensing constraints to build on the limit of beta>-3.3 (90%) derived from an analysis of the luminosity…