Results 21 to 30 of about 94,086 (264)
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
Baryon acoustic oscillations from the cross-correlation of Lyα absorption and quasars in eBOSS DR14 [PDF]
Astronomy & Astrophysics, 2019 We present a measurement of the baryon acoustic oscillation (BAO) scale at redshift z = 2.35 from the three-dimensional correlation of Lyman-α (Lyα) forest absorption and quasars. The study uses 266 590 quasars in the redshift range 1.77 < z < 3.5 from
M. Blomqvist +17 more
semanticscholar +1 more source
A Sample of Quasars with Strong Nitrogen Emission Lines from the Sloan Digital Sky Survey [PDF]
, 2008 We report on 293 quasars with strong NIV] lambda 1486 or NIII] lambda 1750 emission lines (rest-frame equivalent width > 3 \AA) at 1.7 < z < 4.0 selected from the Sloan Digital Sky Survey (SDSS) Fifth Data Release.
Fan, Xiaohui +2 more
core +2 more sources
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
Two Close Separation Quasar-Quasar Pairs in the Large Bright Quasar Survey [PDF]
The Astronomical Journal, 1998 Accepted for publication in the Astronomical Journal, Paper, 4 Figures + 1 ...
Hewett, Paul C. +3 more
openaire +2 more sources
The Small-Scale Environment of Quasars [PDF]
, 2006 Where do quasars reside? Are quasars located in environments similar to those of typical L* galaxies, and, if not, how do they differ? An answer to this question will help shed light on the triggering process of quasar activity.
Bahcall, Neta +3 more
core +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
Spectral Properties of Quasars from Sloan Digital Sky Survey Data Release 14: The Catalog [PDF]
Astrophysical Journal Supplement Series, 2019 We present measurements of the spectral properties for a total of 526,265 quasars, out of which 63% have a continuum signal-to-noise ratio > 3 pixel−1, selected from the fourteenth data release of the Sloan Digital Sky Survey (SDSS-DR14) quasar catalog ...
S. Rakshit, C. .. Stalin, J. Kotilainen
semanticscholar +1 more source
Very high redshift quasars and the rapid emergence of super-massive black holes [PDF]
, 2020 The observation of quasars at very high redshift such as Pōniuā’ena is a challenge for models of supermassive black hole (SMBH) formation. This work presents a study of SMBH formation via known physical processes in starburst clusters formed at the onset
P. Kroupa +3 more
semanticscholar +1 more source
The X-SHOOTER/ALMA Sample of Quasars in the Epoch of Reionization. I. NIR Spectral Modeling, Iron Enrichment, and Broad Emission Line Properties [PDF]
Astrophysical Journal, 2020 We present X-SHOOTER near-IR spectroscopy of a large sample of 38 luminous (M1450 = −29.0 to −24.4) quasars at 5.78 < z < 7.54, which have complementary [C ii]158μm observations from ALMA.
J. Schindler +17 more
semanticscholar +1 more source