Quasar Luminosity Function at z = 7
The Astrophysical Journal Letters, 2023 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, combined with 13 ...
Yoshiki Matsuoka +43 more
doaj +1 more source
High-Redshift Quasars Found in Sloan Digital Sky Survey Commissioning Data II: The Spring Equatorial Stripe [PDF]
, 1999 This is the second paper in a series aimed at finding high-redshift quasars from five-color (u'g'r'i'z') imaging data taken along the Celestial Equator by the Sloan Digital Sky Survey (SDSS) during its commissioning phase.
A. George Pauls +39 more
core +2 more sources
Shedding New Light on Weak Emission-line Quasars in the C iv–Hβ Parameter Space
The Astrophysical Journal, 2023 Weak emission-line quasars (WLQs) are a subset of type 1 quasars that exhibit extremely weak Ly α + N v λ 1240 and/or C iv λ 1549 emission lines. We investigate the relationship between emission-line properties and accretion rate for a sample of 230 ...
Trung Ha +22 more
doaj +1 more source
The Sloan Digital Sky Survey Quasar Lens Search. II. Statistical lens sample from the third data release [PDF]
, 2007 We report the first results of our systematic search for strongly lensed quasars using the spectroscopically confirmed quasars in the Sloan Digital Sky Survey (SDSS).
Anderson, Scott F. +33 more
core +3 more sources
Gaia Space Mission and Quasars
Frontiers in Astronomy and Space Sciences, 2017 Quasars are often considered to be point-like objects. This is largely true and allows for an excellent alignment of the optical positional reference frame of the ongoing ESA mission Gaia with the International Celestial Reference Frame.
Tomaž Zwitter
doaj +1 more source
Target Selection and Validation of DESI Quasars
The Astrophysical Journal, 2023 The Dark Energy Spectroscopic Instrument (DESI) survey will measure large-scale structures using quasars as direct tracers of dark matter in the redshift range 0.9 < z < 2.1 and using Ly α forests in quasar spectra at z > 2.1.
Edmond Chaussidon +56 more
doaj +1 more source
Why radio quiet quasars are preferred over radio loud quasars regardless of environment and redshift [PDF]
The Astrophysical Journal 2020, 2020 Evidence has accumulated suggesting the clustering of radio loud quasars is greater than for radio quiet quasars. We interpret these results in a context in which the fraction of radio loud quasar formation is less than or equal to that for radio quiet quasars for all environments and redshift.
arxiv +1 more source
Obscuration by Gas and Dust in Luminous Quasars [PDF]
, 2014 We explore the connection between absorption by neutral gas and extinction by dust in mid-infrared (IR) selected luminous quasars. We use a sample of 33 quasars at redshifts 0.7 < z < 3 in the 9 deg^2 Bo\"otes multiwavelength survey field that are ...
Brodwin, Mark +3 more
core +3 more sources
The quasar luminosity function at $z\sim5$ via deep learning and Bayesian information criterion [PDF]
, 2022 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 (IGM) in the early universe.
arxiv +1 more source
Determining the fraction of reddened quasars in COSMOS with multiple selection techniques from X-ray to radio wavelengths [PDF]
, 2016 The sub-population of quasars reddened by intrinsic or intervening clouds of dust are known to be underrepresented in optical quasar surveys. By defining a complete parent sample of the brightest and spatially unresolved quasars in the COSMOS field, we ...
Fynbo, J. P. U. +10 more
core +1 more source