Related papers: High-Redshift Quasars Found in Sloan Digital Sky S…

We present a catalog of over 130,000 quasars candidates with NIR photometric properties, with an areal coverage of approximately 1,200 deg^2. This is achieved by matching the Sloan Digital Sky Survey (SDSS) in the optical ugriz bands, to…

In this paper we present the first results of a deep spectroscopic survey of faint quasars in the Sloan Digital Sky Survey (SDSS) Southern Survey, a deep survey carried out by repeatedly imaging a 270 deg^2 area. Quasar candidates were…

The X-ray luminosity function of distant (3<z<5.1) unabsorbed quasars has been measured. A sample of distant high-luminosity quasars ($10^{45} \leq L_{{\rm X},2-10} < 7.5 \times 10^{45}$ erg/s in the 2--10 keV energy band) from the catalog…

Studies of the most luminous quasars at high redshift directly probe the evolution of the most massive black holes in the early Universe and their connection to massive galaxy formation. However, extremely luminous quasars at high redshift…

We present measurements of the spectral properties for a total of 526,265 quasars, out of which 63% have continuum S/N$>3$ pixel$^{-1}$, selected from the fourteenth data release of the Sloan Digital Sky Survey (SDSS-DR14) quasar catalog.…

Over the last few years, the Sloan Digital Sky Survey (SDSS) has discovered several hundred quasars with redshift between 4.0 and 6.4. Including the effects of magnification bias, one expects a priori that an appreciable fraction of these…

We present 13 Broad Absorption Line (BAL) quasars, including 12 new objects, which were identified in the Sloan Digital Sky Survey (SDSS) and matched within 2'' to sources in the FIRST radio survey catalog. The surface density of this…

Multiple color selection techniques have been successful in identifying quasars from wide-field broad-band imaging survey data. Among the quasars that have been discovered so far, however, there is a redshift gap at $5 \lesssim {\rm z}…

The APM multicolor survey for bright z > 4 objects, covering 2500 deg^2 of sky to m(R)~19, resulted in the discovery of thirty-one quasars with z > 4. High signal-to-noise optical spectrophotometry at 5A resolution has been obtained for the…

We present a total of 4784 unique broad absorption line quasars from the Sloan Digital Sky Survey Third Data Release. An automated algorithm was used to match a continuum to each quasar and to identify regions of flux at least 10% below the…

Large-scale surveys over the last years have revealed about 300 QSOs at redshift above 6. Follow-up observations identified surprising properties, such as the very high black hole (BH) masses, spatial correlations with surrounding cold gas…

We observed 17 optically-selected, radio-quiet high-redshift quasars with the Chandra Observatory ACIS, and detected 16 of them. The quasars have redshift between 3.70 and 6.28 and include the highest redshift quasars known. When compared…

The clustering of quasars on small scales yields fundamental constraints on models of quasar evolution and the buildup of supermassive black holes. This paper describes the first systematic survey to discover high redshift binary quasars.…

We present the method and first results of a survey for high-redshift (z>3) radio-loud quasars, which is based on optical identifications of 2902 flat-spectrum radio sources with S(5GHz)>= 25mJy. The radio sample was defined over a 1600 sq…

We present the discovery of two z > 6 quasars, selected as i band dropouts in the VST ATLAS survey. Our first quasar has redshift, z = 6.31 \pm 0.03, z band magnitude, z_AB = 19.63 \pm 0.08 and rest frame 1450A absolute magnitude, M_1450 =…

This is the second installment for the Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) Quasar Survey, which includes quasars observed from September 2013 to June 2015. There are 9024 confirmed quasars in DR2 and 10911 in…

We report on Chandra observations of a sample of 11 optically luminous (Mb<-28.5) quasars at z=3.96-4.55 selected from the Palomar Digital Sky Survey and the Automatic Plate Measuring Facility Survey. These are among the most luminous z>4…

This paper describes the fourth data release of the Sloan Digital Sky Survey (SDSS), including all survey-quality data taken through June 2004. The data release includes five-band photometric data for 180 million objects selected over 6670…

We report the discoveries of the two-image gravitationally lensed quasars, SDSS J0746+4403 and SDSS J1406+6126, selected from the Sloan Digital Sky Survey (SDSS). SDSS J0746+4403, which will be included in our lens sample for statistics and…

Luminous high-redshift quasars can be used to probe of the intergalactic medium (IGM) in the early universe because their UV light is absorbed by the neutral hydrogen along the line of sight. They help us to measure the neutral hydrogen…