Results 21 to 30 of about 111,241 (293)
Pōniuā‘ena: A Luminous z = 7.5 Quasar Hosting a 1.5 Billion Solar Mass Black Hole [PDF]
Astrophysical Journal, 2020 We report the discovery of a luminous quasar, J1007+2115 at z = 7.515 (“Pōniuā‘ena”), from our wide-field reionization-era quasar survey. J1007+2115 is the second quasar now known at z > 7.5, deep into the reionization epoch.
Jinyi Yang +18 more
semanticscholar +1 more source
Spectral Classification of Quasar Subject to Redshift: A Statistical Study
Computer Sciences & Mathematics Forum, 2023 Quasars are astronomical star-like objects having a large ultraviolet flux of radiation accompanied by generally broad emission lines and absorption lines in some cases found at large redshift. The used data is extracted from the Veron Cetti Catalogue of
Prithwish Ghosh, Shinjon Chakraborty
doaj +1 more source
The bolometric quasar luminosity function at z = 0–7 [PDF]
Monthly notices of the Royal Astronomical Society, 2020 In this paper, we provide updated constraints on the bolometric quasar luminosity function (QLF) from z = 0 to z = 7. The constraints are based on an observational compilation that includes observations in the rest-frame IR, B band, UV, soft, and hard ...
Xuejian Shen +6 more
semanticscholar +1 more source
Investigating Gravitationally Lensed Quasars Observable by Nancy Grace Roman Space Telescope
Galaxies, 2023 In this work, we investigate the possibility of observing quasars, particularly lensed quasars, by the Nancy Grace Roman Space Telescope (Roman).
Lindita Hamolli +3 more
doaj +1 more source
Quasars Probing Quasars. X. The Quasar Pair Spectral Database [PDF]
The Astrophysical Journal Supplement Series, 2018 Abstract The rare close projection of two quasars on the sky provides the opportunity to study the host galaxy environment of a foreground quasar in absorption against the continuum emission of a background quasar. For over a decade the “Quasars probing quasars” series has utilized this technique to further the understanding of galaxy ...
J. Xavier Prochaska +11 more
openaire +8 more sources
Quasar: Easy Machine Learning for Biospectroscopy
Cells, 2021 Data volumes collected in many scientific fields have long exceeded the capacity of human comprehension. This is especially true in biomedical research where multiple replicates and techniques are required to conduct reliable studies.
Marko Toplak +3 more
semanticscholar +1 more source
The completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey: BAO and RSD measurements from the anisotropic power spectrum of the quasar sample between redshift 0.8 and 2.2 [PDF]
Monthly notices of the Royal Astronomical Society, 2020 We measure the clustering of quasars of the final data release (DR16) of eBOSS. The sample contains $343\, 708$ quasars between redshifts 0.8 ≤ z ≤ 2.2 over $4699\, \mathrm{deg}^2$.
R. Neveux +24 more
semanticscholar +1 more source
Monthly Notices of the Royal Astronomical Society, 1999 Quasar pairs are either physically distinct binary quasars or the result of gravitational lensing. The majority of known pairs are in fact lenses, with a few confirmed as binaries, leaving a population of objects that have not yet been successfully classified.
Mortlock, D +2 more
openaire +5 more sources
The Large Sky Area Multi-object Fiber Spectroscopic Telescope (LAMOST) Quasar Survey: The Fourth and Fifth Data Releases [PDF]
Astrophysical Journal Supplement Series, 2018 We present Data Releases 4 and 5 of the quasar catalog from the quasar survey by the Large Sky Area Multi-object Fiber Spectroscopic Telescope (LAMOST), which includes quasars observed between 2015 September and 2017 June.
S. Yao +17 more
semanticscholar +1 more source
Reports in Advances of Physical Sciences, 2020 It is an unsolved mystery that the rotation velocity of a galactic disc is same at any radial distances. The presence of dark matter is expected, but not observed.
Shigeto Nagao
doaj +1 more source