Results 1 to 10 of about 112,522 (249)

Performance of the Quasar Spectral Templates for the Dark Energy Spectroscopic Instrument [PDF]

open access: yesThe Astronomical Journal, 2023
Millions of quasar spectra will be collected by the Dark Energy Spectroscopic Instrument (DESI), leading to a fourfold increase in the number of known quasars.
Allyson Brodzeller   +46 more
doaj   +2 more sources

Sentinel-2 enabled E. coli and Enterococcus faecal bacteria surveillance in coastal-recreational waters [PDF]

open access: yesScientific Reports
Monitoring faecal indicator bacteria (FIB), such as Escherichia coli (E. coli) and Enterococcus, in recreational waters is crucial for public health and environmental safety.
Masuma Chowdhury   +2 more
doaj   +2 more sources

The Discovery of a Gravitationally Lensed Quasar at z = 6.51 [PDF]

open access: yesAstrophysical Journal, 2018
Strong gravitational lensing provides a powerful probe of the physical properties of quasars and their host galaxies. A high fraction of the most luminous high-redshift quasars was predicted to be lensed due to magnification bias.
Bian, Fuyan   +19 more
core   +4 more sources

A Cosmological Framework for the Co-Evolution of Quasars, Supermassive Black Holes, and Elliptical Galaxies: I. Galaxy Mergers & Quasar Activity [PDF]

open access: yes, 2007
(Abridged) We develop a model for the cosmological role of mergers in the evolution of starbursts, quasars, and spheroidal galaxies. Combining halo mass functions (MFs) with empirical halo occupation models, we calculate where major galaxy-galaxy mergers
Athanassoula E.   +21 more
core   +2 more sources

Quaia, the Gaia-unWISE Quasar Catalog: An All-sky Spectroscopic Quasar Sample [PDF]

open access: yesAstrophysical Journal, 2023
We present a new, all-sky quasar catalog, Quaia, that samples the largest comoving volume of any existing spectroscopic quasar sample. The catalog draws on the 6,649,162 quasar candidates identified by the Gaia mission that have redshift estimates from ...
Kate Storey-Fisher   +6 more
semanticscholar   +1 more source

A Catalog of Quasar Properties from Sloan Digital Sky Survey Data Release 16 [PDF]

open access: yesAstrophysical Journal Supplement Series, 2022
We present a catalog of continuum and emission-line properties for 750,414 broad-line quasars included in the Sloan Digital Sky Survey Data Release 16 quasar catalog (DR16Q), measured from optical spectroscopy.
Qiaoya Wu, Yue Shen
semanticscholar   +1 more source

Detection of stellar light from quasar host galaxies at redshifts above 6 [PDF]

open access: yesNature, 2022
The detection of starlight from the host galaxies of quasars during the reionization epoch ( z  > 6) has been elusive, even with deep Hubble Space Telescope observations^ 1 , 2 .
Xuheng Ding   +43 more
semanticscholar   +1 more source

A Luminous Quasar at Redshift 7.642 [PDF]

open access: yes, 2021
Distant quasars are unique tracers to study the formation of the earliest supermassive black holes (SMBHs) and the history of cosmic reionization. Despite extensive efforts, only two quasars have been found at z ≥ 7.5, due to a combination of their low ...
Feige Wang   +22 more
semanticscholar   +1 more source

The DESI Survey Validation: Results from Visual Inspection of the Quasar Survey Spectra [PDF]

open access: yesAstronomical Journal, 2022
A key component of the Dark Energy Spectroscopic Instrument (DESI) survey validation (SV) is a detailed visual inspection (VI) of the optical spectroscopic data to quantify key survey metrics. In this paper we present results from VI of the quasar survey
D. Alexander   +71 more
semanticscholar   +1 more source

Gravitationally lensed quasars in Gaia – IV. 150 new lenses, quasar pairs, and projected quasars [PDF]

open access: yesMonthly notices of the Royal Astronomical Society, 2022
We report the spectroscopic follow-up of 175 lensed quasar candidates selected using Gaia Data Release 2 observations following Lemon et al. 2019. Systems include 86 confirmed lensed quasars and a further 17 likely lensed quasars based on imaging and ...
C. Lemon   +12 more
semanticscholar   +1 more source

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