Results 1 to 10 of about 19,774 (165)
Extreme Quasars as Distance Indicators in Cosmology
Frontiers in Astronomy and Space Sciences, 2020 Quasars accreting matter at very high rates (known as extreme Population A [xA] quasars, possibly associated with super-Eddington accreting massive black holes) may provide a new class of distance indicators covering cosmic epochs from present day up to ...
Paola Marziani +2 more
exaly +3 more sources
Highly Accreting Quasars at High Redshift
Frontiers in Astronomy and Space Sciences, 2018 We present preliminary results of a spectroscopic analysis for a sample of type 1 highly accreting quasars (L/LEdd ~ 1.0) at high redshift, z ~2–3.
Andreas Heinz +2 more
exaly +3 more sources
Detecting and Characterizing Young Quasars. III. The Impact of Gravitational Lensing Magnification
The Astrophysical Journal, 2023 We test the impact of gravitational lensing on the lifetime estimates of seven high-redshift quasars at redshift z ≳ 6. The targeted quasars are identified by their small observed proximity zone sizes, which indicate extremely short quasar lifetimes ( t ...
Minghao Yue +10 more
doaj +1 more source
Quasar Clustering and the Lifetime of Quasars [PDF]
The Astrophysical Journal, 2001 ApJ Accepted (Feb 2001). 30 pages, 8 embedded ps figures, AASTEX5. Added discussion of quasar luminosity evolution. Also available at http://www.ociw.edu/~martini/pubs/
Paul Martini +2 more
openaire +4 more sources
The Astrophysical Journal Supplement Series, 2023 We report the fourth installment in the series of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) quasar survey, which includes quasars observed between 2017 September and 2021 June.
Jun-Jie Jin +12 more
doaj +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
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 Astrophysical Journal Letters, 2023 Studies of rest-frame optical emission in quasars at z > 6 have historically been limited by the wavelengths accessible by ground-based telescopes. The James Webb Space Telescope (JWST) now offers the opportunity to probe this emission deep into the ...
Jinyi Yang +55 more
doaj +1 more source
THE PROPERTIES OF QUASAR HOSTS AT THE PEAK OF THE QUASAR ACTIVITY [PDF]
The Astrophysical Journal, 2009 We present near-infrared imaging obtained with ESO VLT/ISAAC of a sample of 16 low luminosity radio-quiet quasars at the epoch around the peak of the quasar activity (2 < z < 3), aimed at investigating their host galaxies. For 11 quasars, we are able to detect the host galaxies and derive their properties, while for the other five quasars, upper ...
Kotilainen J. K. +5 more
openaire +5 more sources