Results 1 to 10 of about 20,355 (150)
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
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
Frontiers in Astronomy and Space Sciences, 2022 Given their extremely large distances and small apparent sizes, quasars are generally considered as objects with near-zero parallax and proper motion.
Qi-Qi Wu +15 more
doaj +1 more source
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 ...
Deborah Dultzin +10 more
doaj +1 more source
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
Galaxies, 2021 The radiative and jet power in active galactic nuclei is generated by accretion of material on to supermassive galactic-centre black holes. For quasars, where the radiative power is by definition very high, objects with high radio luminosities form 10 ...
Gülay Gürkan +5 more
doaj +1 more source
The Pan-STARRS1 z > 5.6 Quasar Survey. II. Discovery of 55 Quasars at 5.6 < z < 6.5
The Astrophysical Journal Supplement Series, 2023 The identification of bright quasars at z ≳ 6 enables detailed studies of supermassive black holes, massive galaxies, structure formation, and the state of the intergalactic medium within the first billion years after the Big Bang.
Eduardo Bañados +22 more
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
The Astrophysical Journal, 2023 We present, for the first time, dark matter halo (DMH) mass measurement of quasars at z ∼ 6 based on a clustering analysis of 107 quasars. Spectroscopically identified quasars are homogeneously extracted from the Hyper Suprime-Cam Strategic Survey ...
Junya Arita +12 more
doaj +1 more source