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Related papers: On the recent discovery claim of a new $z>7$ quasa…

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We report the discovery of a new quasar: SDSS J022155.26-064916.6. This object was discovered while reducing spectra of a sample of stars being considered as spectrophotometric standards for the Dark Energy Survey. The flux and wavelength…

High Energy Astrophysical Phenomena · Physics 2017-09-12 Jacob M. Robertson , Douglas L. Tucker , J. Allyn Smith , William Wester , Haun Lin , Jack H. Mueller , Deborah J. Gulledge

The redshift range from 2.2 to 3, is known as the 'redshift desert' of quasars because quasars with redshift in this range have similar optical colors as normal stars and are thus difficult to be found in optical sky surveys. A quasar…

We present the discovery of a new $z \sim 6.8$ quasar discovered with the near-IR VISTA Hemisphere Survey (VHS) which has been spectroscopically confirmed by the ESO New Technology Telescope (NTT) and the Magellan telescope. This quasar has…

Astrophysics of Galaxies · Physics 2019-02-27 Estelle Pons , Richard G. McMahon , Robert A. Simcoe , Manda Banerji , Paul C. Hewett , Sophie L. Reed

High-redshift quasars are important tracers of structure and evolution in the early universe. However, they are very rare and difficult to find when using color selection because of contamination from late-type dwarfs. High-redshift quasar…

Unlike NASA's original Kepler Discovery Mission, the renewed K2 Mission will stare at the plane of the Ecliptic, observing each field for approximately 75 days. This will bring new opportunities and challenges, in particular the presence of…

Earth and Planetary Astrophysics · Physics 2015-06-23 R. Szabó , K. Sárneczky , Gy. M. Szabó , A. Pál , Cs. P. Kiss , B. Csák , L. Illés , G. Rácz , L. L. Kiss

We present the discovery and preliminary characterization of a gravitationally lensed quasar with a source redshift $z_{s}=2.74$ and image separation of $2.9"$ lensed by a foreground $z_{l}=0.40$ elliptical galaxy. Since the images of…

We present comprehensive photometric characterisation of 2025 FA$_{22}$, a Potentially Hazardous Asteroid (PHA) discovered on 29 March 2025 and observed during the seventh International Asteroid Warning Network (IAWN) coordinated campaign.…

Earth and Planetary Astrophysics · Physics 2026-04-23 Jun Tian , Bin Li , Y. J. Liu , Z. J. Xu , R. Y. Zhai , H. B. Zhao , Anton Pomazan , Fan Li , A. M. Abdelaziz , Y. D. Ping , Wei Liu , Y. D. Mao , Jian Chen , Ahmed. Shokry , Mohamed Ismail

High-redshift quasars are currently the only probes of the growth of supermassive black holes and potential tracers of structure evolution at early cosmic time. Here we present our candidate selection criteria from the Panoramic Survey…

Recently, Carnall et al. discovered two bright high redshift quasars using the combination of the VST ATLAS and WISE surveys. The technique involved using the 3-D colour plane i-z:z-W1:W1-W2 with the WISE W1 (3.4 micron) and W2 (4.5 micron)…

We assemble a catalogue of 488 spectroscopically confirmed very high ($z\geq5.00$) redshift quasars and report their near- ($ZYJHK_{s}/K$) and mid- (WISE W1234) infrared properties. 97\% of the VH$z$Q sample is detected in one or more NIR…

Astrophysics of Galaxies · Physics 2020-05-08 Nicholas P. Ross , Nicholas J. G. Cross

Luminous quasars at $z>4$ provide key insights into the early Universe. Their rarity necessitates wide-field multi-band surveys to efficiently separate them from the main astrophysical contaminants (i.e., ultracool dwarfs). To expand the…

Studying quasars at the highest redshifts can constrain models of galaxy and black hole formation, and it also probes the intergalactic medium in the early universe. Optical surveys have to date discovered more than 60 quasars up to z~6.4,…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 B. P. Venemans , J. R. Findlay , W. J. Sutherland , G. De Rosa , R. G. McMahon , R. Simcoe , E. A. Gonzalez-Solares , K. Kuijken , J. R. Lewis

This is the fourth paper in a series of publications aiming at discovering quasars at the epoch of reionization. In this paper, we expand our search for $z\sim 7$ quasars to the footprint of the Dark Energy Survey (DES) Data Release One…

Photometric selection of luminous high-redshift ($z\gtrsim4$) quasars is plagued by contamination from numerous low-mass Galactic stars, reddened lower-redshift quasars, as well as compact luminous red galaxies. Confirmation of these rare…

We present details of a new sample of radio-loud quasars drawn from 0.013 sr of the 7C Redshift Survey. This sample is small (21 quasars) but complete in that every object with an unresolved nucleus and/or broad emission lines with…

Astrophysics · Physics 2016-01-27 Chris J. Willott , Steve Rawlings , Katherine M. Blundell , Mark Lacy

Quasars are galaxies hosting accreting supermassive black holes; due to their brightness, they are unique probes of the early universe. To date, only few quasars have been reported at $z > 6.5$ ($<$800 Myr after the Big Bang). In this work,…

We present a new algorithm to estimate quasar photometric redshifts (photo-$z$s), by considering the asymmetries in the relative flux distributions of quasars. The relative flux models are built with multivariate Skew-t distributions in the…

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